NASA Selects Mission to Study Causes of Giant Solar Particle Storms

A new NASA mission called SunRISE will study what drives solar particle storms – giant surges of solar particles that erupt off of the Sun – as depicted in this illustration. Understanding how such storms affect interplanetary space can help protect spacecraft and astronauts. Credits: NASA

NASA has selected a new mission to study how the Sun generates and releases giant space weather storms – known as solar particle storms – into planetary space. Not only will such information improve understanding of how our solar system works, but it ultimately can help protect astronauts traveling to the Moon and Mars by providing better information on how the Sun’s radiation affects the space environment they must travel through.

The new mission, called the Sun Radio Interferometer Space Experiment (SunRISE), is an array of six CubeSats operating as one very large radio telescope. NASA has awarded $62.6 million to design, build and launch SunRISE by no earlier than July 1, 2023.

NASA chose SunRISE in August 2017 as one of two Mission of Opportunity proposals to conduct an 11-month mission concept study. In February 2019, the agency approved a continued formulation study of the mission for an additional year. SunRISE is led by Justin Kasper at the University of Michigan in Ann Arbor and managed by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.

"We are so pleased to add a new mission to our fleet of spacecraft that help us better understand the Sun, as well as how our star influences the space environment between planets," said Nicky Fox, director of NASA's Heliophysics Division. "The more we know about how the Sun erupts with space weather events, the more we can mitigate their effects on spacecraft and astronauts."

The mission design relies on six solar-powered CubeSats – each about the size of a toaster oven – to simultaneously observe radio images of low-frequency emission from solar activity and share them via NASA’s Deep Space Network. The constellation of CubeSats would fly within 6 miles of each other, above Earth's atmosphere, which otherwise blocks the radio signals SunRISE will observe. Together, the six CubeSats will create 3D maps to pinpoint where giant particle bursts originate on the Sun and how they evolve as they expand outward into space. This, in turn, will help determine what initiates and accelerates these giant jets of radiation. The six individual spacecraft will also work together to map, for the first time, the pattern of magnetic field lines reaching from the Sun out into interplanetary space.

NASA's Missions of Opportunity maximize science return by pairing new, relatively inexpensive missions with launches on spacecraft already approved and preparing to go into space. SunRISE proposed an approach for access to space as a hosted rideshare on a commercial satellite provided by Maxar of Westminster, Colorado, and built with a Payload Orbital Delivery System, or PODS. Once in orbit, the host spacecraft will deploy the six SunRISE spacecraft and then continue its prime mission.

Missions of Opportunity are part of the Explorers Program, which is the oldest continuous NASA program designed to provide frequent, low-cost access to space using principal investigator-led space science investigations relevant to the Science Mission Directorate’s (SMD) astrophysics and heliophysics programs. The program is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for SMD, which conducts a wide variety of research and scientific exploration programs for Earth studies, space weather, the solar system and universe.

For more information about the Explorers Program, visit: https://explorers.gsfc.nasa.gov

For information about NASA's heliophysics missions and activities, visit: https://www.nasa.gov/sunearth

Grey Hautaluoma / Karen Fox

Headquarters, Washington

202-358-0668 / 301-286-6284

grey.hautaluoma-1@nasa.gov / karen.fox@nasa.gov

Editor: Sean Potter

Source: NASA/Space Weather

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Electron-eating neon causes star to collapse

Figure 1: An artist’s impression shows how an imaginary Neon footballfish (having Neon-Sign) eats away at the electrons inside a star core. (Credit: Kavli IPMU)

An international team of researchers has found that neon inside a certain massive star can eat so many electrons in the core, a process called electron capture, which causes the star to collapse into a neutron star and produce a supernova.

The researchers were interested in studying the final fate of stars within a mass range of 8 to 10 solar masses, or 8 to 10 times the mass of our Sun. This mass range is important because it includes the boundary between whether a star has a large enough mass to undergo a supernova explosion to form a neutron star, or has a smaller mass to form a white dwarf star without becoming a supernova.

An 8 to 10 solar mass star commonly forms a core composed of oxygen, magnesium, and neon (figure 1). The core is rich in degenerate-electrons, meaning there is an abundance of electrons in a dense space, whose energy is high enough to sustain the core against gravity. Once the core density is high enough, the electrons get eaten by magnesium and then neon, which also found inside the core. Past studies have confirmed that magnesium and neon can start eating away at the electrons once the mass of the core has grown close to a Chandrasekhar’s limiting mass, a process called electron capture, but there has been debate about whether electron capture can cause neutron star formation.

A team of researchers including Chinese University of Hong Kong PhD candidate Shuai Zha (frequent visitor to the Kavli Institute for the Physics and Mathematics of the Universe, Kavli IPMU, and currently a postdoctoral fellow at Stockholm University), Kavli IPMU WPI postdoctoral fellow Shing-Chi Leung (currently a postdoctoral fellow at Caltech), Nihon University Professor Toshio Suzuki, and Kavli IPMU Senior Scientist Ken'ichi Nomoto studied the evolution of an 8.4 solar mass star and ran computer simulations on it to find an answer.

Figure 2: (a) A star core contains oxygen, neon, and magnesium. Once the core density becomes high enough, (b) magnesium and neon begin eating electrons and inducing a collapse. (c) Then oxygen burning is ignited and produces iron-group-nuclei and free-protons, which eat more and more electrons to promote further collapse of the core. (d) Finally, the collapsing core becomes a neutron star in the center, and the outer layer explodes to produce a supernova. (Credit: Zha et al.)

Using newly updated data by Suzuki for density-dependent and temperature-dependent electron capture rates, they simulated the evolution of the star’s core, which is supported by the pressure of degenerate electrons against the star’s own gravity. As magnesium and mainly neon eat the electrons, the number of electrons decreased and the core rapidly shrunk (Figure 2).

Figure 3: The Crab Nebula, a remnant of the supernova in 1054 (SN 1054; observed by ancient astronomers in China, Japan and Arab). Nomoto et al. (1982) suggested that SN 1054 could be caused by Electron Capture Supernova of a star with the initial mass of about 9 times the Sun. (Credit: NASA, ESA, J. DePasquale (STScI), and R. Hurt (Caltech/IPAC)).

The electron capture also released heat. When the central density of the core exceeded 1010 g/cm3, oxygen in the core started to burn materials in the central region of the core, turning them into iron-group-nuclei such as iron and nickel. The temperature became so hot that protons became free and escaped. Now, the electrons became easier to be captured by free protons and iron-group-nuclei, and the density was so high that the core collapsed without producing a thermonuclear explosion.

With the new electron capture rates, oxygen burning was found to take place slightly off-center. Nevertheless, the collapse formed a neutron star and caused a supernova explosion, showing that an electron capture supernova takes place.

Note a certain mass range of stars with 8 to 10 solar masses would form white dwarfs composed of oxygen-magnesium-neon by losing envelope due to stellar wind mass loss. If the wind mass loss is small, on the other hand, the star undergoes the electron capture supernova as found in their simulation.

The team suggests that the electron capture supernova could explain the properties of the supernova recorded in 1054 that formed the Crab Nebula, as proposed Nomoto et al. (1982 Nature) (Figure 3).

These results were published in The Astrophysical Journal on November 15, 2019.

Source: Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)

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Paper details

Journal: The Astrophysical Journal Title: Evolution of ONeMg Core in Super-AGB Stars toward Electron-capture Supernovae: Effects of Updated Electron-capture Rate Authors: Shuai Zha (1), Shing-Chi Leung (2), Toshio Suzuki (3,4), and Ken'ichi Nomoto (2)

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Author affiliations:

1 Department of Physics, The Chinese University of Hong Kong, Hong Kong S.A.R., Peoples Republic of China 

2 Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan

3 Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3, Setagaya-ku, Tokyo 156-8550, Japan 4 Visiting Researcher, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan.

DOI: https://doi.org/10.3847/1538-4357/ab4b4b (Published 15 November, 2019)

Research contact

Ken'ichi Nomoto
Senior Scientist
Kavli Institute for th
e Physics and Mathematics of the Universe
University of Tokyo
E-mail: nomoto@astron.s.u-tokyo.ac.jp

Media contact

Motoko Kakubayashi
Press officer
Kavli Institute for the Physics and Mathematics of the Universe
University of Tokyo
TEL：+81-4-7136-5980
E-mail: press@ipmu.jp

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Signals from Neutron Star Binaries

Artist's illustration of a binary star system consisting of two highly magnetized neutron stars.

Credit: John Rowe Animations

Fast radio bursts (FRBs) are brief radio signals that last on the order of milliseconds. They appear to be extragalactic, coming from small, point-like areas on the sky. Some FRBs are one-off events, while others are periodic or “repeating”. The sources of FRBs are still unknown, but binary neutron star systems might be a piece of the puzzle.

Wanted: A Reliable Source of Repeating Fast Radio Bursts

Any proposed model for a repeating FRB must explain a number of observed behaviors. Among them are the following:

1. Repeating bursts from a given FRB source are consistent in frequency and overall intensity on the timescale of years.
2. Bursts exhibit small-scale variations in measures of the source’s magnetic environment.
3. FRBs seem to be preferentially hosted in massive, Milky-Way-like galaxies.

Example of an FRB from a repeating source, showing the intensity and various frequencies contained in a single burst (darker means more intense, lighter means less intense). The red lines just below and above 550 MHz and those near 450 MHz and 650 MHz indicate frequencies that were unused due to other radio signals interfering [adapted from the CHIME/FRB Collaboration, Andersen et al.2019].

Binary neutron stars (BNSs) have been considered as possible solutions to the repeating FRB puzzle. Specifically, binary neutron star mergers might producIn a recent study, Bing Zhang (University of Nevada Las Vegas; Kyoto University, Japan) attempts to explain repeating FRBs using BNSs in a novel way. Instead of considering the neutron-star merger itself, Zhang examined whether the years leading up to the merger could produce repeating FRBs.e FRBs, along with gamma-ray bursts and gravitational waves. But how could BNSs produce repeating, consistent FRBs?

In a recent study, Bing Zhang (University of Nevada Las Vegas; Kyoto University, Japan) attempts to explain repeating FRBs using BNSs in a novel way. Instead of considering the neutron-star merger itself, Zhang examined whether the years leading up to the merger could produce repeating FRBs.

A Magnetic Dance

Repeating FRBs put out an enormous amount of energy over a few milliseconds — at least as much energy as the Sun puts out over three days. To put constraints on the average FRB-producing BNS, Zhang used the double-pulsar system PSR J0737-3039A/B (pulsars are fast-rotating neutron stars with strong magnetic fields), which is very well characterized in terms of its component stars and overall structure.

Aside from having enormous amounts of rotational energy intrinsically and in their orbits, BNSs also have strong magnetic fields. These magnetic fields are key to the production of FRBs in Zhang’s scenario — as the neutron stars orbit each other, their magnetic fields interact, possibly triggering a flow of particles that would produce FRBs.

On the scale of centuries or even decades pre-merger, these triggers could occur repeatedly and consistently, satisfying a key requirement for repeating FRBs. This picture of interacting magnetic fields would also explain the small-scale variations in the magnetic environment measures, and there is an overlap between the sorts of galaxies that host FRBs and those that host the gamma-ray bursts that could be associated with BNS mergers.

By Way of Gravitational Waves

An observational test for this scenario is the detection of gravitational waves from an FRB source. Space-based gravitational wave detectors, such as the Laser Interferometer Space Antenna, would be well-suited for this. Ground-based detectors would also play a role, picking up waves from the BNSs actually merging.

And of course, the more FRBs we observe, the more we can narrow down their properties and sources. Fortunately, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is predicted to detect 2 to 50 FRBs per day, and other radio telescopes are hard at work as well. So maybe this FRB mystery will be solved sooner than we think!

Citation

“Fast Radio Bursts from Interacting Binary Neutron Star Systems,” Bing Zhang 2020 ApJL 890 L24. https://doi.org/10.3847/2041-8213/ab7244

By Tarini Konchady

Source: American Astronomical Society (AAS)

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Quasars Tsunamis rip across galaxies

This is an artist's concept of a distant galaxy with an active quasar at its center. A quasar emits exceptionally large amounts of energy generated by a supermassive black hole fueled by infalling matter. Using the unique capabilities of the Hubble Space Telescope, astronomers have discovered that blistering radiation pressure from the vicinity of the black hole pushes material away from the galaxy's center at a fraction of the speed of light. The "quasar winds" are propelling hundreds of solar masses of material each year. This affects the entire galaxy as the material snowplows into surrounding gas and dust. Credits:NASA, ESA, J. Olmsted (STSci) and N. Arav (Virginia Tech),.  Hi-res image

Using the unique capabilities of NASA's Hubble Space Telescope, a team of astronomers has discovered the most energetic outflows ever witnessed in the universe. They emanate from quasars and tear across interstellar space like tsunamis, wreaking havoc on the galaxies in which the quasars live.

Quasars are extremely remote celestial objects, emitting exceptionally large amounts of energy. Quasars contain supermassive black holes fueled by infalling matter that can shine 1,000 times brighter than their host galaxies of hundreds of billions of stars.

As the black hole devours matter, hot gas encircles it and emits intense radiation, creating the quasar. Winds, driven by blistering radiation pressure from the vicinity of the black hole, push material away from the galaxy's center. These outflows accelerate to breathtaking velocities that are a few percent of the speed of light.

"No other phenomena carries more mechanical energy. Over the lifetime of 10 million years, these outflows produce a million times more energy than a gamma-ray burst," explained principal investigator Nahum Arav of Virginia Tech in Blacksburg, Virginia. "The winds are pushing hundreds of solar masses of material each year. The amount of mechanical energy that these outflows carry is up to several hundreds of times higher than the luminosity of the entire Milky Way galaxy."

The quasar winds snowplow across the galaxy's disk. Material that otherwise would have formed new stars is violently swept from the galaxy, causing star birth to cease. Radiation pushes the gas and dust to far greater distances than scientists previously thought, creating a galaxy-wide event.

As this cosmic tsunami slams into interstellar material, the temperature at the shock front spikes to billions of degrees, where material glows largely in X-rays, but also widely across the light spectrum. Anyone witnessing this event would see a brilliant celestial display. "You'll get lots of radiation first in X-rays and gamma rays, and afterwards it will percolate to visible and infrared light," said Arav. "You'd get a huge light show—like Christmas trees all over the galaxy."

Numerical simulations of galaxy evolution suggest that such outflows can explain some important cosmological puzzles, such as why astronomers observe so few large galaxies in the universe, and why there is a relationship between the mass of the galaxy and the mass of its central black hole. This study shows that such powerful quasar outflows should be prevalent in the early universe.

"Both theoreticians and observers have known for decades that there is some physical process that shuts off star formation in massive galaxies, but the nature of that process has been a mystery. Putting the observed outflows into our simulations solves these outstanding problems in galactic evolution," explained eminent cosmologist Jeremiah P. Ostriker, of Columbia University in New York and Princeton University in New Jersey.

Astronomers studied 13 quasar outflows, and they were able to clock the breakneck speed of gas being accelerated by the quasar wind by looking at spectral "fingerprints" of light from the glowing gas. The Hubble ultraviolet data show that these light absorption features created from material along the path of the light were shifted in the spectrum because of the fast motion of the gas across space. This is due to the Doppler effect, where the motion of an object compresses or stretches wavelengths of light depending on whether it is approaching or receding from us. Only Hubble has the specific range of ultraviolet sensitivity that allows for astronomers to obtain the necessary observations leading to this discovery.

Aside from measuring the most energetic quasars ever observed, the team also discovered another outflow accelerating faster than any other. It increased from nearly 43 million miles per hour to roughly 46 million miles per hour in a three-year period. The scientists believe its acceleration will continue to increase over time.

"Hubble's ultraviolet observations allow us to follow the whole range of energy output from quasars, from cooler gas to the extremely hot, highly ionized gas in the more massive winds," added team member Gerard Kriss of the Space Telescope Science Institute in Baltimore, Maryland. "These were previously only visible with much more difficult X-ray observations. Such powerful outflows may yield new insights into the link between the growth of a central supermassive black hole and the development of its entire host galaxy."

The team also includes graduate student Xinfeng Xu and postdoctoral researcher Timothy Miller, both of Virginia Tech, as well as Rachel Plesha of the Space Telescope Science Institute in Baltimore, Maryland. The findings were published in a series of six papers in March 2020, as a focus issue of The Astrophysical Journal Supplements.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

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Contact:

Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu

Nahum Arav
Virginia Tech, Blacksburg, Virginia
arav@vt.edu

Related Links:

• The science paper by N. Arav et al.
• NASA's Hubble Portal
• The Astrophysical Journal Supplements

Source: HubbleSite/News

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Chandra Data Tests "Theory of Everything"

Perseus Cluster

Credit: NASA/CXC/Univ. of Cambridge/C. Reynolds et al.

JPEG (547 kb) - Large JPEG (6.4 MB) - Tiff (19.5 MB) - More Images

A Tour of Chandra Data Tests "Theory of Everything" - More Animations 

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Astronomers using NASA's Chandra X-ray Observatory have made one of the first experimental tests of string theory, a set of models intended to tie together all known forces, particles, and interactions. As described in our latest press release, researchers used Chandra to look for signs of an as-yet undetected particle predicted by string theory. The lack of a detection in these Chandra observations helps rule out some versions of string theory.

The team looked for extraordinarily low-mass "axion-like" particles in the Perseus galaxy cluster, shown in a Chandra image in the main panel of this graphic (red, green and blue colors are low, medium and high X-ray energies respectively). Galaxy clusters, the largest structures in the Universe held together by gravity, offer an excellent opportunity to search for these particles. In a galaxy cluster, X-ray photons from an embedded or a background source can travel through a large amount of hot gas permeated with magnetic field lines. Some of the X-ray photons may undergo conversion into axion-like particles, or the other way around, along this journey. A simplified illustration shows this process, with shorter wavelength X-ray photons (in blue) converting into axion-like particles (yellow) and back to photons, as they travel across magnetic field lines (grey) in the cluster. Longer wavelength X-ray photons (red) are converting into axion-like particles, but not back into photons. Such conversions would cause a distortion in the X-ray spectrum (the amount of X-rays at different energies) of a bright or embedded source of X-rays.

Photon/Particle Illustration

Credit: Amanda Smith/Institute of Astronomy/University of Cambridge 

Astronomers obtained a long Chandra observation, lasting over five days, of the central supermassive black hole in the center of the Perseus galaxy cluster (shown in the inset.) The spectrum of the region around the black hole showed no distortions, allowing the team to rule out the presence of most types of axion-like particles in the relatively low mass range their search was sensitive to.

Here the Chandra spectrum (red) of Perseus' central black hole shows the intensity of X-rays as a function of X-ray energy, along with an example (black) of a model X-ray spectrum predicted if axion-like particles were actually being converted from and into photons. To highlight the distortions that could have been detected, the data divided by the example model are also shown.

Chandra Spectrum

Credit: NASA/CXC/Univ. of Cambridge/C. Reynolds et al. 

One possible interpretation of this work is that axion-like particles do not exist. Another possible interpretation is that the particles undergo conversion from and into photons less easily than some particle physicists have expected. They also could have higher masses than probed with the Chandra data.

There has been a surge of interest in studies of these particles in recent years for three reasons: First, despite a lot of work, there continues to be no detection of Weakly Interacting Massive Particles (WIMPs), either with gamma-ray observations, or earth-based experiments that could explain the nature of dark matter. These particles are predicted to interact with normal matter only via the weak force, and have been considered to be one of the strongest candidates for dark matter. Secondly, scientists have realized that axions and axion-like particles are predicted by string theory. Finally, there are a large number of experiments or observations that can be done to search for these particles.

A paper describing these results appeared in the February 10th, 2020 issue of The Astrophysical Journal and is available online. The authors are Christopher Reynolds (University of Cambridge, UK), David Marsh (Stockholm University, Sweden), Helen Russell (University of Nottingham, UK), Andrew C. Fabian (University of Cambridge), Robyn Smith (University of Maryland in College Park, Francesco Tombesi (University of Rome, Italy), and Sylvain Veilleux (University of Maryland).

NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science and flight operations from Cambridge and Burlington, Massachusetts.

A Quick Look at Chandra Data Tests "Theory of Everything"

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Fast Facts for Perseus Cluster:


Scale: Main image is about 8 arcmin (550,000 light years) across. Inset image is about 11 arcsec (13,000 light years) across.
Category: Groups & Clusters of Galaxies, Black Holes
Coordinates (J2000): RA 03h 19m 47.60s | Dec +41° 30´ 37.00"
Constellation: Perseus

Observation Date: Main image: 25 pointings between Sep 1999 and Dec 2009; Inset: 15 pointings between Jun 2017 and Dec 2017

Observation Time: Main Image: 17 days 8 hours 37 minutes; Inset: 5 days 16 hours 30 minutes

Obs. ID: Main Image: 502, 503, 1513, 3209, 3404, 4289, 4946-4953, 6139, 6145, 6146, 11713-11716, 12025, 12033, 12036, 12037; Inset: 20449-20451, 20823-20827, 20837-20844

Instrument: ACIS
Also Known As: Abell 426
References: Reynolds, C.S., et. al., 2020, ApJ, 890, 59; arXiv:1907.05475
Color Code: Red = 0.5-1.2 keV, Green = 1.2-2.0 keV, Blue = 2.0-7.0 keV
Distance Estimate: About 240 million light years

Source: NASA’s Chandra X-ray Observatory

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The Strange Orbits of ‘Tatooine’ Planetary Disks

Two examples of aligned and misaligned protoplanetary disks around binary stars (circumbinary disks), observed with ALMA. Binary star orbits are added for clarity. Left: in star system HD 98800 B, the disk is misaligned with inner binary stars. The stars are orbiting each other (in this view, towards and away from us) in 315 days. Right: in star system AK Sco, the disk is in line with the orbit of its binary stars. The stars are orbiting each other in 13.6 days. Credit: ALMA (ESO/NAOJ/NRAO), I. Czekala and G. Kennedy; NRAO/AUI/NSF, S. Dagnello.  Hi-Res File

Ian Czekala of the University of California at Berkeley explains his research on 'Tatooine' protoplanetary disks.

Credit: NRAO/AUI/NSF. Download Video

Artist impression of a double sunset on a 'Tatooine' exoplanet forming in a circumbinary disk that is misaligned with the orbits of its binary stars. Credit: NRAO/AUI/NSF, S. Dagnello.  Hi-Res File

Animation showing the aligned and misaligned circumbinary disks around binary star systems AK Sco and HD 98800 B. Credit: ALMA (ESO/NAOJ/NRAO), I. Czekala and G. Kennedy; NRAO/AUI/NSF, S. Dagnello.  Download Video

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are severely tilted. These systems can teach us about planet formation in complex environments.

In the last two decades, thousands of planets have been found orbiting stars other than our Sun. Some of these planets orbit two stars, just like Luke Skywalker’s home Tatooine. Planets are born in protoplanetary disks – we now have wonderful observations of these thanks to ALMA – but most of the disks studied so far orbit single stars. ‘Tatooine’ exoplanets form in disks around binary stars, so-called circumbinary disks.

Studying the birthplaces of ‘Tatooine’ planets provides a unique opportunity to learn about how planets form in different environments. Astronomers already know that the orbits of binary stars can warp and tilt the disk around them, resulting in a circumbinary disk misaligned relative to the orbital plane of its host stars. For example, in a 2019 study led by Grant Kennedy of the University of Warwick, UK, ALMA found a striking circumbinary disk in a polar configuration.

“With our study, we wanted to learn more about the typical geometries of circumbinary disks,” said astronomer Ian Czekala of the University of California at Berkeley. Czekala and his team used ALMA data to determine the degree of alignment of nineteen protoplanetary disks around binary stars. “The high resolution ALMA data was critical for studying some of the smallest and faintest circumbinary disks yet,” said Czekala.

The astronomers compared the ALMA data of the circumbinary disks with the dozen ‘Tatooine’ planets that have been found with the Kepler space telescope. To their surprise, the team found that the degree to which binary stars and their circumbinary disks are misaligned is strongly dependent on the orbital period of the host stars. The shorter the orbital period of the binary star, the more likely it is to host a disk in line with its orbit. However, binaries with periods longer than a month typically host misaligned disks.

“We see a clear overlap between the small disks, orbiting compact binaries, and the circumbinary planets found with the Kepler mission,” Czekala said. Because the primary Kepler mission lasted 4 years, astronomers were only able to discover planets around binary stars that orbit each other in fewer than 40 days. And all of these planets were aligned with their host star orbits. A lingering mystery was whether there might be many misaligned planets that Kepler would have a hard time finding. “With our study, we now know that there likely isn’t a large population of misaligned planets that Kepler missed, since circumbinary disks around tight binary stars are also typically aligned with their stellar hosts,” added Czekala.

Still, based on this finding, the astronomers conclude that misaligned planets around wide binary stars should be out there and that it would be an exciting population to search for with other exoplanet-finding methods like direct imaging and microlensing. (NASA’s Kepler mission used the transit method, which is one of the ways to find a planet.)

Czekala now wants to find out why there is such a strong correlation between disk (mis)alignment and the binary star orbital period. “We want to use existing and coming facilities like ALMA and the next generation Very Large Array to study disk structures at exquisite levels of precision,” he said, “and try to understand how warped or tilted disks affect the planet formation environment and how this might influence the population of planets that form within these disks.”

“This research is a great example of how new discoveries build on previous observations,” said Joe Pesce, National Science Foundation Program Officer for NRAO and ALMA. “Discerning trends in the circumbinary disk population was only made possible by building on the foundation of archival observational programs undertaken by the ALMA community in previous cycles.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement

Source:  National Radio Astronomy Observatory (NRAO)/News

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Media contact:

Iris Nijman
News and Public Information Manager
National Radio Astronomy Observatory (NRAO)
inijman@nrao.edu
+1 (434) 296-0314

Science contact:

Ian Czekala
University of California at Berkeley
iczekala@berkeley.edu
+1 (631) 793 9292

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Ian Czekala worked with Eugene Chiang of the University of California at Berkeley; Sean Andrews, Guillermo Torres and David Wilner of the Harvard & Smithsonian Center for Astrophysics; Eric Jensen of Swarthmore College; Keivan Stassun of Vanderbilt University; and Bruce Macintosh of Stanford University.

The astronomers published their results in The Astrophysical Journal. https://iopscience.iop.org/article/10.3847/1538-4357/ab287b

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Black Hole Team Discovers Path to Razor-Sharp Black Hole Images

The image of a black hole has a bright ring of emission surrounding a "shadow" cast by the black hole. This ring is composed of a stack of increasingly sharp subrings that correspond to the number of orbits that photons took around the black hole before reaching the observer. Credit: George Wong (UIUC) and Michael Johnson (CfA). Low Resolution (jpg)

The image of Black Hole
Credit: George Wong (UIUC) and Michael Johnson (CfA)

High Resolution (jpg)

Low Resolution (jpg)

Black holes cast a shadow on the image of bright surrounding material because their strong gravitational field can bend and trap light. The shadow is bounded by a bright ring of light, corresponding to photons that pass near the black hole before escaping. The ring is actually a stack of increasingly sharp subrings, and the n-th subring corresponds to photons that orbited the black hole n/2 times before reaching the observer. This animation shows how a black hole image is formed from these subrings and the trajectories of photons that create the image. Credit: Center for Astrophysics | Harvard & Smithsonian. animation.mp4

Cambridge, MA - Last April, the Event Horizon Telescope (EHT) sparked international excitement when it unveiled the first image of a black hole. Today, a team of researchers have published new calculations that predict a striking and intricate substructure within black hole images from extreme gravitational light bending.

"The image of a black hole actually contains a nested series of rings," explains Michael Johnson of the Center for Astrophysics | Harvard and Smithsonian (CfA). "Each successive ring has about the same diameter but becomes increasingly sharper because its light orbited the black hole more times before reaching the observer. With the current EHT image, we've caught just a glimpse of the full complexity that should emerge in the image of any black hole."

Because black holes trap any photons that cross their event horizon, they cast a shadow on their bright surrounding emission from hot infalling gas. A "photon ring" encircles this shadow, produced from light that is concentrated by the strong gravity near the black hole. This photon ring carries the fingerprint of the black hole—its size and shape encode the mass and rotation or "spin" of the black hole. With the EHT images, black hole researchers have a new tool to study these extraordinary objects.

"Black hole physics has always been a beautiful subject with deep theoretical implications, but now it has also become an experimental science," says Alex Lupsasca from the Harvard Society of Fellows. "As a theorist, I am delighted to finally glean real data about these objects that we've been abstractly thinking about for so long."

The research team included observational astronomers, theoretical physicists, and astrophysicists.

"Bringing together experts from different fields enabled us to really connect a theoretical understanding of the photon ring to what is possible with observation," notes George Wong, a physics graduate student at the University of Illinois at Urbana-Champaign. Wong developed software to produce simulated black hole images at higher resolutions than had previously been computed and to decompose these into the predicted series of sub-images. "What started as classic pencil-and-paper calculations prompted us to push our simulations to new limits."

The researchers also found that the black hole's image substructure creates new possibilities to observe black holes. "What really surprised us was that while the nested subrings are almost imperceptible to the naked eye on images—even perfect images—they are strong and clear signals for arrays of telescopes called interferometers," says Johnson. "While capturing black hole images normally requires many distributed telescopes, the subrings are perfect to study using only two telescopes that are very far apart. Adding one space telescope to the EHT would be enough."

The results were published in Science Advances.

This research was supported by grants from the National Science Foundation, the Gordon and Betty Moore Foundation, the John Templeton Foundation, and NASA.

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About Center for Astrophysics | Harvard & Smithsonian

Headquartered in Cambridge, Mass., the Center for Astrophysics | Harvard & Smithsonian (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

Tyler Jump
Public Affairs
Center for Astrophysics | Harvard & Smithsonian
+1 617-495-7462
tyler.jump@cfa.harvard.edu

Source: Harvard-Smithsonian Center for Astrophysics (CfA)

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On the Origin of Massive Stars

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A massive laboratory

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Wide-field view of the Tarantula Nebula and its surroundings (ground-based image)

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Videos

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Zoom-in on LHA 120-N150

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Pan across LHA 120-N150

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This scene of stellar creation, captured by the NASA/ESA Hubble Space Telescope, sits near the outskirts of the famous Tarantula Nebula. This cloud of gas and dust, as well as the many young and massive stars surrounding it, is the perfect laboratory to study the origin of massive stars.

The bright pink cloud and the young stars surrounding it in this image taken with the NASA/ESA Hubble Space Telescope have the uninspiring name LHA 120-N 150. This region of space is located on the outskirts of the Tarantula Nebula, which is the largest known stellar nursery in the local Universe. The nebula is situated over 160 000 light-years away in the Large Magellanic Cloud, a neighbouring irregular dwarf galaxy that orbits the Milky Way.

The Large Magellanic Cloud has had one or more  close encounters in the past, possibly with the Small Magellanic Cloud. These interactions have caused an episode of energetic star formation in our tiny neighbour — part of which is visible as the Tarantula Nebula.

Also known as 30 Doradus or NGC 2070, the Tarantula Nebula owes its name to the arrangement of bright patches that somewhat resemble the legs of a tarantula. It measures nearly 1000 light-years across. Its proximity, the favourable inclination of the Large Magellanic Cloud, and the absence of intervening dust make the Tarantula Nebula one of the best laboratories in which to study the formation of stars, in particular massive stars. This nebula has an exceptionally high concentration of massive stars, often referred to as super star clusters.

Astronomers have studied LHA 120-N 150 to learn more about the environment in which massive stars form. Theoretical models of the formation of massive stars suggest that they should form within clusters of stars; but observations indicate that up to ten percent of them also formed in isolation. The giant Tarantula Nebula with its numerous substructures is the perfect laboratory in which to resolve this puzzle as in it massive stars can be found both as members of clusters and in isolation.

With the help of Hubble, astronomers try to find out whether the isolated stars visible in the nebula truly formed alone or just moved away from their stellar siblings. However, such a study is not an easy task; young stars, before they are fully formed — especially massive ones — look very similar to dense clumps of dust.

LHA 120-N 150 contains several dozen of these objects. They are a mix of unclassified sources — some probably young stellar objects and others probably dust clumps. Only detailed analysis and observations will reveal their true nature and that will help to finally solve the unanswered question of the origin of massive stars.

Hubble has observed the Tarantula Nebula and its substructures in the past — always being interested in the formation and evolution of stars.

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More Information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The scientific results of this observation were previously published in the Astrophyiscal Journal.

Image credit: ESA/Hubble, NASA, I. Stephens.

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Links

• Images of Hubble 
• Images of the Tarantula Nebula

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Contacts

Bethany Downer

ESA/Hubble, Public Information Officer

Garching, Germany

Email: bethany.downer@partner.eso.org

Source: ESA/Hubble/News

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A Star-Bursting Galaxy Born from the Collision of Dwarfs

This 2.5 x 2.5 arcminute image shows VCC 848, a compact dwarf galaxy that scientists think formed from the merger of two smaller galaxies. Click for the full view! [Adapted from Zhang et al. 2020]

What happens when the large-scale drama of a violent galaxy merger plays out on small scales for a pair of dwarf galaxies? New observations document the scene of a recent dwarf-galaxy collision.

Dramatic Encounters

When two galaxies merge, the collision can have dramatic consequences — particularly if the galaxies are rich in gas. The gravitational interaction of galaxies oscillating during a merger drives shock waves through their gas. This can trigger bursts of star formation, launch jets from active galactic nuclei, and result in the eventual formation of a new galaxy with drastically different morphology than the original merging pair.

We’ve seen this drama play out on large scales between giant galaxies, but we know a lot less about what happens when dwarf galaxies collide. Dwarf galaxies are the most abundant type of galaxy in the universe, but they’re also very small and faint. This poses a significant challenge to finding and studying dwarfs — which means there’s a lot we don’t know about how the mergers of dwarf galaxies impact overall star formation and the shape of the new galaxy that forms in the collision.

Fortunately, we may now have an opportunity to learn more. In a recent publication led by Hong-Xin Zhang (University of Science and Technology of China), a team of scientists reports on the discovery of a small, compact galaxy formed by the collision of two dwarfs.

This g-band image of VCC 848 better shows the galaxy’s three extended shell-like structures (outlined with red arcs) surrounding the central body of stars. [Adapted from Zhang et al. 2020]

Feeling Shell-Shocked

VCC 848 is what’s known as a blue compact dwarf galaxy — a small galaxy that’s actively undergoing a burst of star formation. Located in the outskirts of the Virgo Cluster some 65 million light-years away, this little dwarf shows telltale signs of a recent merger: careful analysis reveals a complex set of three extended shell-like structures of stars around the bright stellar main body.

Shell structures — which, previously, had only been detected in larger galaxies — are known to be a signature of a recent minor or major galaxy merger; they are formed as the merger sends ripples through the galaxy and disrupts its structure. The detection of these shells in such a small galaxy provides evidence that we’re looking at the recent merger of two dwarfs.

A Flurry of Activity

Zhang and collaborators use their observations of VCC 848 — made with the MegaCam instrument on the Canada–France–Hawaii Telescope in Hawaii — to analyze the stars of the galaxy and learn more about its history.

They determine that the two dwarfs that collided were likely similar in mass to within a factor of a few, and the merger triggered a burst of star formation over the past billion years that was ~7–10 times higher than normal. This enhancement in star formation peaked near the center of the galaxy a few hundred million years ago, and it’s since declined; current star formation activity is primarily in VCC 848’s outer regions.

VCC 848 is just one of several blue compact dwarfs with hints of tidal shells that the authors uncovered in their survey, so there’s more data on the way! We have a lot more to learn about what happens when tiny galaxies collide.

The average formation rate per billion years of star clusters above a certain birth mass, for the age intervals of 0–1 Gyr and 1–13 Gyr. This indicates that star formation was significantly more active in the last billion years. [Adapted from Zhang et al. 2020]

Citation

“The Blue Compact Dwarf Galaxy VCC 848 Formed by Dwarf–Dwarf Merging,” Hong-Xin Zhang et al 2020 ApJL 891 L23. doi:10.3847/2041-8213/ab7825

By Susanna Kohler 

Source: American Astronomical Society (AAS) Nova  

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Cannibalistic Andromeda

PAndAS map showing the stellar halo of Andromeda, traced using red giant stars. A wide variety of stellar streams and over-densities are apparent, representing the shredded remains of cannibalised galaxies. Overplotted are the positions of 77 globular clusters, discovered in PAndAS, and observed spectroscopically for the present paper. Clusters with motions towards us are coloured blue, and away from us are coloured red. Credit: Mackey and PAndAS team

The Violent History of the Big Galaxy Next Door

Astronomers have pieced together the cannibalistic past of the neighbouring large galaxy Andromeda, which has set its sights on our Milky Way as the main course.

The galactic detective work found that Andromeda has eaten several smaller galaxies, likely within the last few billion years, with left-overs found in large streams of stars.

Australian National University (ANU) researcher Dr Dougal Mackey, who co-led the study with Professor Geraint Lewis from the University of Sydney, said the international research team also found very faint traces of more small galaxies that Andromeda gobbled up even earlier, perhaps as far back as during its first phases of formation about 10 billion years ago.

“The Milky Way is on a collision course with Andromeda in about four billion years, so knowing what kind of a monster our galaxy is up against is useful in finding out its ultimate fate,” said Dr Mackey from the ANU Research School of Astronomy and Astrophysics.

“Andromeda has a much bigger and more complex stellar halo than the Milky Way, which indicates that it has cannibalised many more galaxies, possibly larger ones.”

The signs of ancient feasting are written in the stars orbiting Andromeda, with the team studying dense groups of stars, known as globular clusters, to reveal the ancient mealtimes.

“By tracing the faint remains of these smaller galaxies with embedded star clusters, we’ve been able to recreate the way Andromeda drew them in and ultimately enveloped them at the different times,” Dr Mackey said.

The discovery presents several new mysteries, with the two bouts of galactic feeding coming from completely different directions.

“This is very weird and suggests that the extragalactic meals are fed from what’s known as the ‘cosmic web’ of matter that threads the universe,” said Professor Lewis from the Sydney Institute for Astronomy and University of Sydney School of Physics.

“More surprising is the discovery that the direction of the ancient feeding is the same as the bizarre ‘plane of satellites’, an unexpected alignment of dwarf galaxies orbiting Andromeda.”

Dr Mackey and Professor Lewis were part of a team that previously discovered such planes were fragile and rapidly destroyed by Andromeda’s gravity within a few billion years.

“This deepens the mystery as the plane must be young, but it appears to be aligned with ancient feeding of dwarf galaxies. Maybe this is because of the cosmic web, but really, this is only speculation,” Professor Lewis said.

“We’re going to have to think quite hard to unravel what this is telling us,” he said.

Dr Mackey said studying Andromeda also informed understanding about the way our galaxy has grown and evolved over many billions of years. “One of our main motivations in studying astronomy is to understand our place in the Universe. A way of learning about our galaxy is to study others that are similar to it, and try to understand how these systems formed and evolved. Sometimes this can actually be easier than looking at the Milky Way, because we live inside it and that can make certain types of observations quite difficult.”

The study, published in Nature, analysed data from the Pan-Andromeda Archaeological Survey, known as PAndAS. The Canada-France-Hawaii Telescope (CFHT) observed the PAndAS program from 2008-2010 as part of CFHT's large program observations. PAndAS used CFHT's wide field optical imager MegaCam for 226 hours spread over the two year period. The goal of the program was to provide the deepest and most complete panorama of galactic halos for the Milky Way's nearest neighbors, M33, the Triangulum galaxy, and M31, the Andromeda galaxy. The PAndAS team intended to create the primary reference dataset for all subsequent studies of the stellar populations of M31 and M33.

"CFHT and the PAndAS team spent considerable time crafting the observing strategy for the program with the hope that the survey would lead to discoveries like those made by Dr. Mackey's team," said Todd Burdullis, queue observations specialist at CFHT. "We are incredibly proud of the dataset and its continuing impact on astronomy's understanding of the histories of our nearest neighbors."

“We are cosmic archaeologists, except we are digging through the fossils of long-dead galaxies rather than human history,” said Professor Lewis, who is a leading member of the survey.

The team involved institutions from Australia, New Zealand, the United Kingdom, Netherlands, Canada, France and Germany.

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Additional information

Link to the paper

arXiv.org link to paper

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Hawaii Media Contact:

Mary Beth Laychak
Canada-France-Hawaii Telescope
808-885-3121
laychak@cfht.hawaii.edu

Will Wright
the ANU media hotline
Telephone: +612 6125 7979 or +61 2 6100 3486
media@anu.edu.au

Marcus Strom
University of Sydney
Telephone: +61 2 8627 6433 or +61 423 982 485
marcus.strom@sydney.edu.au

Science Contact

Dr. Dougal Mackey
Research School of Astronomy and Astrophysics
ANU College of Science
Telephone: +61 2 6125 0214
dougal.mackey@anu.edu.au

Professor Geraint Lewis
Sydney Institute for Astronomy
School of Physics, University of Sydney
Telephone: +61 424 254 551
geraint.lewis@sydney.edu.au

Source:  Canada-France-Hawaii Telescope (CFHT)/News

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ESO Telescope Observes Exoplanet Where It Rains Iron

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Artist’s impression of the night side of WASP-76

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Another artist’s impression of WASP-76b

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Videos

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ESOcast 218: The Stranger Exoplanets

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A ‘fly to’ WASP-76, the star around which WASP-76b orbits

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A view of the orbit of WASP-76b around its host star WASP-76

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Researchers using ESO’s Very Large Telescope (VLT) have observed an extreme planet where they suspect it rains iron. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where it condenses into iron droplets.

“One could say that this planet gets rainy in the evening, except it rains iron,” says David Ehrenreich, a professor at the University of Geneva in Switzerland. He led a study, published today in the journal Nature, of this exotic exoplanet. Known as WASP-76b, it is located some 640 light-years away in the constellation of Pisces.

This strange phenomenon happens because the 'iron rain' planet only ever shows one face, its day side, to its parent star, its cooler night side remaining in perpetual darkness. Like the Moon on its orbit around the Earth, WASP-76b is ‘tidally locked’: it takes as long to rotate around its axis as it does to go around the star.

On its day side, it receives thousands of times more radiation from its parent star than the Earth does from the Sun. It’s so hot that molecules separate into atoms, and metals like iron evaporate into the atmosphere. The extreme temperature difference between the day and night sides results in vigorous winds that bring the iron vapour from the ultra-hot day side to the cooler night side, where temperatures decrease to around 1500 degrees Celsius.

Not only does WASP-76b have different day-night temperatures, it also has distinct day-night chemistry, according to the new study. Using the new ESPRESSO instrument on ESO’s VLT in the Chilean Atacama Desert, the astronomers identified for the first time chemical variations on an ultra-hot gas giant planet. They detected a strong signature of iron vapour at the evening border that separates the planet’s day side from its night side. “Surprisingly, however, we do not see the iron vapour in the morning,” says Ehrenreich. The reason, he says, is that “it is raining iron on the night side of this extreme exoplanet.”

“The observations show that iron vapour is abundant in the atmosphere of the hot day side of WASP-76b," adds María Rosa Zapatero Osorio, an astrophysicist at the Centre for Astrobiology in Madrid, Spain, and the chair of the ESPRESSO science team. "A fraction of this iron is injected into the night side owing to the planet's rotation and atmospheric winds. There, the iron encounters much cooler environments, condenses and rains down."

This result was obtained from the very first science observations done with ESPRESSO, in September 2018, by the scientific consortium who built the instrument: a team from Portugal, Italy, Switzerland, Spain and ESO.

ESPRESSO — the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations — was originally designed to hunt for Earth-like planets around Sun-like stars. However, it has proven to be much more versatile. “We soon realised that the remarkable collecting power of the VLT and the extreme stability of ESPRESSO made it a prime machine to study exoplanet atmospheres,” says Pedro Figueira, ESPRESSO instrument scientist at ESO in Chile.

“What we have now is a whole new way to trace the climate of the most extreme exoplanets,” concludes Ehrenreich.

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Notes

• A previous version of this press release mistakenly indicated the distance to WASP-76b as being 390 light-years, based on a 2016 study. More recent data indicates that the exoplanet is 640 light-years away.

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More information

This research was presented in a paper to appear in Nature.

The team is composed of David Ehrenreich (Observatoire astronomique de l’Université de Genève, Geneva, Switzerland [UNIGE]), Christophe Lovis (UNIGE), Romain Allart (UNIGE), María Rosa Zapatero Osorio (Centro de Astrobiología, Madrid, Spain [CSIC-INTA]), Francesco Pepe (UNIGE), Stefano Cristiani (INAF Osservatorio Astronomico di Trieste, Italy [INAF Trieste]), Rafael Rebolo (Instituto de Astrofísica de Canarias, Tenerife, Spain [IAC]), Nuno C. Santos (Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, Portugal [IA/UPorto] & Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal [FCUP]), Francesco Borsa (INAF Osservatorio Astronomico di Brera, Merate, Italy [INAF Brera]), Olivier Demangeon (IA/UPorto), Xavier Dumusque (UNIGE), Jonay I. González Hernández (IAC), Núria Casasayas-Barris (IAC), Damien Ségransan (UNIGE), Sérgio Sousa (IA/UPorto), Manuel Abreu (Instituto de Astrofísica e Ciências do Espaço, Universidade de Lisboa, Portugal [IA/FCUL] & Departamento de Física da Faculdade de Ciências da Universidade de Lisboa, Portugal [FCUL], Vardan Adibekyan [IA/UPorto], Michael Affolter (Physikalisches Institut & Center for Space and Habitability, Universität Bern, Switzerland [Bern]), Carlos Allende Prieto (IAC), Yann Alibert (Bern), Matteo Aliverti (INAF Brera), David Alves (IA/FCUL & FCUL), Manuel Amate (IA/UPorto), Gerardo Avila (European Southern Observatory, Garching bei München, Germany [ESO]), Veronica Baldini (INAF Trieste), Timothy Bandy (Bern), Willy Benz (Bern), Andrea Bianco (INAF Brera), Émeline Bolmont (UNIGE), François Bouchy (UNIGE), Vincent Bourrier (UNIGE), Christopher Broeg (Bern), Alexandre Cabral (IA/FCUL & FCUL), Giorgio Calderone (INAF Trieste), Enric Pallé (IAC), H. M. Cegla (UNIGE), Roberto Cirami (INAF Trieste), João M. P. Coelho (IA/FCUL & FCUL), Paolo Conconi (INAF Brera), Igor Coretti (INAF Trieste), Claudio Cumani (ESO), Guido Cupani (INAF Trieste), Hans Dekker (ESO), Bernard Delabre (ESO), Sebastian Deiries (ESO), Valentina D’Odorico (INAF Trieste & Scuola Normale Superiore, Pisa, Italy), Paolo Di Marcantonio (INAF Trieste), Pedro Figueira (European Southern Observatory, Santiago de Chile, Chile [ESO Chile] & IA/UPorto), Ana Fragoso (IAC), Ludovic Genolet (UNIGE), Matteo Genoni (INAF Brera), Ricardo Génova Santos (IAC), Nathan Hara (UNIGE), Ian Hughes (UNIGE), Olaf Iwert (ESO), Florian Kerber (ESO), Jens Knudstrup (ESO), Marco Landoni (INAF Brera), Baptiste Lavie (UNIGE), Jean-Louis Lizon (ESO), Monika Lendl (UNIGE & Space Research Institute, Austrian Academy of Sciences, Graz, Austria), Gaspare Lo Curto (ESO Chile), Charles Maire (UNIGE), Antonio Manescau (ESO), C. J. A. P. Martins (IA/UPorto & Centro de Astrofísica da Universidade do Porto, Portugal), Denis Mégevand (UNIGE), Andrea Mehner (ESO Chile), Giusi Micela (INAF Osservatorio Astronomico di Palermo, Italy), Andrea Modigliani (ESO), Paolo Molaro (INAF Trieste & Institute for Fundamental Physics of the Universe, Trieste, Italy), Manuel Monteiro (IA/UPorto), Mario Monteiro (IA/UPorto & FCUP), Manuele Moschetti (INAF Brera), Eric Müller (ESO), Nelson Nunes (IA), Luca Oggioni (INAF Brera), António Oliveira (IA/FCUL & FCUL), Giorgio Pariani (INAF Brera), Luca Pasquini (ESO), Ennio Poretti (INAF Brera & Fundación Galileo Galilei, INAF, Breña Baja, Spain), José Luis Rasilla (IAC), Edoardo Redaelli (INAF Brera), Marco Riva (INAF Brera), Samuel Santana Tschudi (ESO Chile), Paolo Santin (INAF Trieste), Pedro Santos (IA/FCUL & FCUL), Alex Segovia Milla (UNIGE), Julia V. Seidel (UNIGE), Danuta Sosnowska (UNIGE), Alessandro Sozzetti (INAF Osservatorio Astrofisico di Torino, Pino Torinese, Italy), Paolo Spanò (INAF Brera), Alejandro Suárez Mascareño (IAC), Hugo Tabernero (CSIC-INTA & IA/UPorto), Fabio Tenegi (IAC), Stéphane Udry (UNIGE), Alessio Zanutta (INAF Brera), Filippo Zerbi (INAF Brera).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with AustralIA/FCULas a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

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Links

• Research paper
• Photos of ESPRESSO
• Photos of the VLT
• More about ESPRESSO and how it finds exoplanets

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Contacts

David Ehrenreich

Associate Professor at the University of Geneva

Geneva, Switzerland

Tel: +41 22 379 23 90

Email: david.ehrenreich@unige.ch

Francesco Pepe

Professor at the University of Geneva and Principal Investigator of the ESPRESSO consortium

Geneva, Switzerland

Tel: +41 22 379 23 96

Email: francesco.pepe@unige.ch

María Rosa Zapatero Osorio

Chair of the ESPRESSO science team at Centro de Astrobiología (CSIC-INTA)

Madrid, Spain

Tel: +34 9 15 20 64 27

Email: mosorio@cab.inta-csic.es

Pedro Figueira

Astronomer at ESO and Instituto de Astrofísica e Ciências do Espaço, instrument scientist of ESPRESSO

Santiago, Chile

Tel: +56 2 2463 3074

Email: pedro.figueira@eso.org

Nuno C. Santos

Co-principal investigator of the ESPRESSO consortium at Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto and Departamento de Física e Astronomia Faculdade de Ciências, Universidade do Porto

Porto, Portugal

Tel: +351 226 089 893

Email: nuno.santos@astro.up.pt

Stefano Cristiani

Co-principal investigator of the ESPRESSO consortium at INAF Astronomical Observatory of Trieste

Trieste, Italy

Tel: +39 040 3199220

Email: stefano.cristiani@inaf.it

Bárbara Ferreira

ESO Public Information Officer

Garching bei München, Germany

Tel: +49 89 3200 6670

Cell: +49 151 241 664 00

Email: pio@eso.org

Source: ESO/News

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