Detailing the Formation of Distant Solar Systems with NASA's Webb Telescope

PDS 70 is approximately 370 light-years away and features a large gap in its inner ring. The European Southern Observatory's Very Large Telescope provided the first clear image of a planet forming around the central star in 2018. The planet is a bright point to the right of the center of the image. The central star is black since its light was blocked by an instrument known as a coronagraph. A second planet has also been detected. This system is a future target of NASA’s James Webb Space Telescope. Credit: ESO/A. Müller et al.

This infographic is an simplified artistic representation of planet formation, following the format of a baking recipe.

Credits: L. Hustak (STScI) .
Hi-res image

We live in a mature solar system—eight planets and several dwarf planets (like Pluto) have formed, the latter within the rock- and debris-filled region known as the Kuiper Belt. If we could turn back time, what would we see as our solar system formed? While we can’t answer this question directly, researchers can study other systems that are actively forming—along with the mix of gas and dust that encircles their still-forming stars—to learn about this process.

A team led by Dr. Thomas Henning of the Max Planck Institute for Astronomy in Heidelberg, Germany, will employ NASA's upcoming James Webb Space Telescope to survey more than 50 planet-forming disks in various stages of growth to determine which molecules are present and ideally pinpoint similarities, helping to shape what we know about how solar systems assemble.

Their research with Webb will specifically focus on the inner disks of relatively nearby, forming systems. Although information about these regions has been obtained by previous telescopes, none match Webb's sensitivity, which means many more details will pour in for the first time. Plus, Webb's space-based location about a million miles (1.5 million kilometers) from Earth will give it an unobstructed view of its targets. "Webb will provide unique data that we can't get any other way," said Inga Kamp of the Kapteyn Astronomical Institute of the University of Groningen in the Netherlands. "Its observations will provide molecular inventories of the inner disks of these solar systems."

This research program will primarily gather data in the form of spectra. Spectra are like rainbows—they spread out light into its component wavelengths to reveal high-resolution information about the temperatures, speeds, and compositions of the gas and dust. This incredibly rich information will allow the researchers to construct far more detailed models of what is present in the inner disks—and where. "If you apply a model to these spectra, you can find out where molecules are located and what their temperatures are," Henning explained.

These observations will be incredibly valuable in helping the researchers pinpoint similarities and differences among these planet-forming disks, which are also known as protoplanetary disks. "What can we learn from spectroscopy that we can't learn from imaging? Everything!" Ewine van Dishoeck of Leiden University in the Netherlands exclaimed. "One spectrum is worth a thousand images."

A 'Mountain' of New Data

Researchers have long studied protoplanetary disks in a variety of wavelengths of light, from radio to near-infrared. Some of the team's existing data are from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, which collects radio light. ALMA excels at constructing images of the outer disks. If you were to compare the span of their outer disks to the size of our Solar System, this region is past Saturn's orbit. Webb's data will complete the picture by helping researchers model the inner disks.

Some data already exist about these inner disks—NASA's retired Spitzer Space Telescope served as a pathfinder—but Webb's sensitivity and resolution are required to identify the precise quantities of each molecule as well as the elemental compositions of the gas with its data, known as spectra. "What used to be a very blurry peak in the spectrum will consist of hundreds if not thousands of detailed spectral lines," van Dishoeck said.

Webb's specialty in mid-infrared light is particularly important. It will enable researchers to identify the "fingerprints" of molecules like water, carbon dioxide, methane, and ammonia—which can't be identified with any other existing instruments. The observatory will also determine how starlight impacts the chemistry and physical structures of the disks.

Protoplanetary disks are complex systems. As they form, their mix of gas and dust is distributed into rings across the system. Their materials travel from the outer disk to the inner disk—but how? "The inner portion of the disk is a very dynamic place," explains Tom Ray of the Dublin Institute for Advanced Studies in Ireland. "It's not only where terrestrial-type planets form, but it's also where supersonic jets are launched by the star."

Jets emitted by the star lead to a mixing of elements in the inner and outer disks, both by sending out particles and permitting other particles to move inward. "We think that as material leaves, it loses its spin, or angular momentum, and that this allows other material to move inward," Ray continued. "These exchanges of material will obviously impact the chemistry of the inner disk, which we’re excited to explore with Webb."

Exciting Insights Await

PDS 70 is farther at 370 light-years away. It also has a large gap in its inner ring, plus data have revealed that two forming planets, known as protoplanets, are present and gathering material. "Webb's mid-infrared measurements will help us refine what we know about them, as well as the material around them," Kamp explained.

With dozens of targets on their list, it's difficult for team members to play favorites. "I love them all," Henning said. "One question I'd like to answer concerns the connection between the composition of planet-forming disks and the planets themselves. With Webb, we will observe far more detail about which types of material are available for a potential planet to accrete."

After refining the data, his team will apply the discrete data points to models. "This will allow us to do a graphic reconstruction of these systems," he continued. These models will be shared with the astronomical community, enabling other scientists to examine the data, and make their own projections or glean new findings. These studies will be conducted through a Guaranteed Time Observations (GTO) program.

The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

By Claire Blome
Space Telescope Science Institute, Baltimore, Md.

Editor: Lynn Jenner

Source: NASA/Solar System and Beyond

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A pair of lonely planet-like objects born like stars

Artist’s composition of the two brown dwarfs, in the foreground Oph 98B in purple, in the background Oph 98A in red. Credit: Thibaut Roger

An international research team led by the University of Bern has discovered an exotic binary system composed of two young planet-like objects, orbiting around each other from a very large distance. Although these objects look like giant exoplanets, they formed in the same way as stars, proving that the mechanisms driving star formation can produce rogue worlds in unusual systems deprived of a Sun.

Star-forming processes sometimes create mysterious astronomical objects called brown dwarfs, which are smaller and colder than stars, and can have masses and temperatures down to those of exoplanets in the most extreme cases. Just like stars, brown dwarfs often wander alone through space, but can also be seen in binary systems, where two brown dwarfs orbit one another and travel together in the galaxy.

Researchers led by Clémence Fontanive from the Center for Space and Habitability (CSH) and the NCCR PlanetS discovered a curious starless binary system of brown dwarfs. The system CFHTWIR-Oph 98 (or Oph 98 for short) consists of the two very low-mass objects Oph 98 A and Oph 98 B. It is located 450 light-years away from Earth in the stellar association Ophiuchus. The researchers were surprised by the fact that Oph 98 A and B are orbiting each other from a strikingly large distance, about 5 times the distance between Pluto and the Sun, which corresponds to 200 times the distance between the Earth and the Sun. The study has just been published in The Astrophysical Journal Letters.

Extremely low masses and a very large separation

The pair is a rare example of two objects similar in many aspects to extra-solar giant planets, orbiting around each other with no parent star. The more massive component, Oph 98 A, is a young brown dwarf with a mass of 15 times that of Jupiter, which is almost exactly on the boundary separating brown dwarfs from planets. Its companion, Oph 98 B, is only 8 times heavier than Jupiter.

Components of binary systems are tied by an invisible link called gravitational binding energy, and this bond gets stronger when objects are more massive or closer to one another. With extremely low masses and a very large separation, Oph 98 has the weakest binding energy of any binary system known to date.

Dr. Clémence Fontanive, Center for Space and Habitability (CSH) and NCCR PlanetS, University of Bern, 

Credit: University of Bern

Discovery thanks to data from Hubble

Clémence Fontanive and her colleagues discovered the companion to Oph 98 A using images from the Hubble Space Telescope. Fontanive says: “Low-mass brown dwarfs are very cold and emit very little light, only through infrared thermal radiation. This heat glow is extremely faint and red, and brown dwarfs are hence only visible in infrared light.” Furthermore, the stellar association in which the binary is located, Ophiuchus, is embedded in a dense, dusty cloud which scatters visible light. “Infrared observations are the only way to see through this dust”, explains the lead researcher. “Detecting a system like Oph 98 also requires a camera with a very high resolution, as the angle separating Oph 98 A and B is a thousand times smaller than the size of the moon in the sky,” she adds. The Hubble Space Telescope is among the few telescopes capable of observing objects as faint as these brown dwarfs, and able to resolve such tight angles.

Because brown dwarfs are cold enough, water vapor forms in their atmospheres, creating prominent features in the infrared that are commonly used to identify brown dwarfs. However, these water signatures cannot be easily detected from the surface of the Earth. Located above the atmosphere in the vacuum of space, Hubble allows to probe the existence of water vapor in astronomical objects. Fontanive explains: “Both objects looked very red and showed clear signs of water molecules. This immediately confirmed that the faint source we saw next to Oph 98 A was very likely to also be a cold brown dwarf, rather than a random star that happened to be aligned with the brown dwarf in the sky.”

The team also found images in which the binary was visible, collected 14 years ago with the Canada-France-Hawaii Telescope (CFHT) in Hawaii. “We observed the system again this summer from another Hawaiian observatory, the United Kingdom Infra-Red Telescope. Using these data, we were able to confirm that Oph 98 A and B are moving together across the sky over time, relative to other stars located behind them, which is evidence that they are bound to each other in a binary pair”, explains Fontanive.

An atypical result of star formation

The Oph 98 binary system formed only 3 million years ago in the nearby Ophiuchus stellar nursery, making it a newborn on astronomical timescales. The age of the system is much shorter than the typical time needed to build planets. Brown dwarfs like Oph 98 A are formed by the same mechanisms as stars. Despite Oph 98 B being the right size for a planet, the host Oph 98 A is too small to have a sufficiently large reservoir of material to build a planet that big. “This tells us that Oph 98 B, like its host, must have formed through the same mechanisms that produce stars and shows that the processes that create binary stars operate on scale-down versions all the way down to these planetary masses”, comments Clémence Fontanive.

With the discovery of two planet-like worlds – already uncommon products of star formation – bound to each other in such an extreme configuration, “we are really witnessing an incredibly rare output of stellar formation processes”, as Fontanive describes.

 

Source: National Centre of Competence in Research PlanetS (NCCR)/News

Dark Storm on Neptune Reverses Direction, Possibly Shedding a Fragment

Hubble Uncovers a Pair of Dark Vortices on Neptune 

Credits:  NASA, ESA, M.H. Wong (University of California, Berkeley), and A. Simon (NASA Goddard Space Flight Center).  Release images - Release Video

Rotation of Neptune

Astronomers using NASA's Hubble Space Telescope watched a mysterious dark vortex on Neptune abruptly steer away from a likely death on the giant blue planet.

The storm, which is wider than the Atlantic Ocean, was born in the planet's northern hemisphere and discovered by Hubble in 2018. Observations a year later showed that it began drifting southward toward the equator, where such storms are expected to vanish from sight. To the surprise of observers, Hubble spotted the vortex change direction by August 2020, doubling back to the north. Though Hubble has tracked similar dark spots over the past 30 years, this unpredictable atmospheric behavior is something new to see.

Equally as puzzling, the storm was not alone. Hubble spotted another smaller dark spot in January this year that temporarily appeared near its larger cousin. It might possibly have been a piece of the giant vortex that broke off, drifted away, and then disappeared in subsequent observations.

"We are excited about these observations because this smaller dark fragment is potentially part of the dark spot’s disruption process," said Michael H. Wong of the University of California at Berkeley. "This is a process that's never been observed. We have seen some other dark spots fading away and they're gone, but we've never seen anything disrupt, even though it’s predicted in computer simulations."

The large storm, which is 4,600 miles across, is the fourth dark spot Hubble has observed on Neptune since 1993. Two other dark storms were discovered by the Voyager 2 spacecraft in 1989 as it flew by the distant planet, but they had disappeared before Hubble could observe them. Since then, only Hubble has had the sharpness and sensitivity in visible light to track these elusive features, which have sequentially appeared and then faded away over a duration of about two years each. Hubble uncovered this latest storm in September 2018.

Wicked Weather

Neptune's dark vortices are high-pressure systems that can form at mid-latitudes and may then migrate toward the equator. They start out remaining stable due to Coriolis forces, which cause northern hemisphere storms to rotate clockwise, due to the planet's rotation. (These storms are unlike hurricanes on Earth, which rotate counterclockwise because they are low-pressure systems.) However, as a storm drifts toward the equator, the Coriolis effect weakens and the storm disintegrates. In computer simulations by several different teams, these storms follow a more-or-less straight path to the equator, until there is no Coriolis effect to hold them together. Unlike the simulations, the latest giant storm didn't migrate into the equatorial "kill zone."

"It was really exciting to see this one act like it's supposed to act and then all of a sudden it just stops and swings back," Wong said. "That was surprising."

Dark Spot Jr.

The Hubble observations also revealed that the dark vortex’s puzzling path reversal occurred at the same time that a new spot, informally deemed "dark spot jr.," appeared. The newest spot was slightly smaller than its cousin, measuring about 3,900 miles across. It was near the side of the main dark spot that faces the equator—the location that some simulations show a disruption would occur.

However, the timing of the smaller spot's emergence was unusual. "When I first saw the small spot, I thought the bigger one was being disrupted," Wong said. "I didn't think another vortex was forming because the small one is farther towards the equator. So it's within this unstable region. But we can't prove the two are related. It remains a complete mystery.

"It was also in January that the dark vortex stopped its motion and started moving northward again," Wong added. "Maybe by shedding that fragment, that was enough to stop it from moving towards the equator."

The researchers are continuing to analyze more data to determine whether remnants of dark spot jr. persisted through the rest of 2020.

Dark Storms Still Puzzling

It's still a mystery how these storms form, but this latest giant dark vortex is the best studied so far. The storm's dark appearance may be due to an elevated dark cloud layer and it could be telling astronomers about the storm's vertical structure.

Another unusual feature of the dark spot is the absence of bright companion clouds around it, which were present in Hubble images taken when the vortex was discovered in 2018. Apparently, the clouds disappeared when the vortex halted its southward journey. The bright clouds form when the flow of air is perturbed and diverted upward over the vortex, causing gases to likely freeze into methane ice crystals. The lack of clouds could be revealing information on how spots evolve, say researchers.

Weather Eye on the Outer Planets

Hubble snapped many of the images of the dark spots as part of the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project, led by Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland, that annually captures global maps of our solar system's outer planets when they are closest to Earth in their orbits.

OPAL's key goals are to study long-term seasonal changes, as well as capture comparatively transitory events, such as the appearance of dark spots on Neptune or potentially Uranus. These dark storms may be so fleeting that in the past some of them may have appeared and faded during multi-year gaps in Hubble's observations of Neptune. The OPAL program ensures that astronomers won't miss another one.

"We wouldn't know anything about these latest dark spots if it wasn't for Hubble," Simon said. "We can now follow the large storm for years and watch its complete life cycle. If we didn't have Hubble, then we might think the Great Dark Spot seen by Voyager in 1989 is still there on Neptune, just like Jupiter's Great Red Spot. And, we wouldn't have known about the four other spots Hubble discovered." Wong will present the team's findings Dec. 15 at the fall meeting of the American Geophysical Union.

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.

Contacts:

Media Contacts:

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu

Science Contacts:
Michael H. Wong
University of California, Berkeley, California
HubbleSite

Amy Simon
NASA Goddard Space Flight Center, Greenbelt, Maryland
amy.simon@nasa.gov

 References:

• NASA's Hubble Portal
• M.H. Wong et al. (2020) Presentation Abstract at Fall AGU Meeting
• Hubble Sees Neptune's Mysterious Shrinking Storm 

Source: HubbleSite/News

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A Radio Flare from Colliding Stars?

When neutron stars collide, the shell of expanding ejecta can interact with the surrounding interstellar medium, producing long-lived radio flaring. [NASA's Goddard Space Flight Center/CI Lab].Hi-res image

When a pair of neutron stars collide, they emit a fireworks show. Could some of the low-energy light produced in these mergers be detectable years later? A team of scientists thinks so — and they’re pretty sure they’ve found an example.

A Rainbow of Signals

In addition to gravitational waves, a slew of electromagnetic radiation is produced in the merger of two neutron stars, spanning the spectrum from gamma rays to radio waves.

In 2017, the now-famous neutron star collision GW170817 gave us a first look at this expected emission: it revealed a short gamma-ray burst, infrared and optical light from ejecta in a kilonova, and relatively short-lived X-ray and radio afterglows caused by high-speed outflows.

But there’s one expected type of emission that was missing from GW170817, and it’s never before been spotted in any neutron star collision: radio flaring.

Illustration of radio emission from a neutron star merger. During the merger, some neutron star matter is flung outward. This ejecta interacts with the interstellar gas, producing a years-long radio flare. [Lee et al. 2020].Hi-res image

Radio Secrets revealed 

Models of neutron star mergers predict that when ejecta are flung out from the stellar collision, they’ll expand into space, eventually running into the surrounding medium of interstellar gas and dust. The subsequent interaction of the ejecta with the interstellar medium should produce radio flaring.

The emission from these radio flares is expected to be quite long-lived — lasting for years or even decades — which means we could hope to find these signals long after the time of the explosion that produced them. But radio flares are also likely to be relatively faint, so we could only expect to spot flares from nearby collisions (within ~650 million light-years). Additionally, only mergers that occur in environments with dense surrounding gas and dust will light up brightly enough for us to spot.

With these constraints, it’s perhaps not surprising that we haven’t found any radio flares marking past mergers yet. But a team of scientists led by Kyung-hwan Lee (University of Florida) recently waded through decades of radio data from the Very Large Array — and in a recent publication, they’re announcing that one transient may be the first identified radio flare from a stellar collision.

Observational data for FIRST J1419+3940 and best-fit radio light curves at three different frequencies. The data are better fit by the neutron-star-merger model (solid lines) than the long-gamma-ray-burst model (dashed lines). [Lee et al. 2020] . Hi-res image

A Decade-Old Collisions

FIRST J141918.9+394036 is a radio transient located in a dwarf galaxy 280 million light-years away. Lee and collaborators compile survey data on this source spanning 23 years and evaluate possible explanations for the radio emission.

While this source could potentially be explained as a long-gamma-ray-burst afterglow — light from an off-axis jet produced by a collapsing star — the radio data aren’t fit best by this picture. Instead, the authors show via models that this transient’s light curve is best described as the decay of a radio flare, just as predicted from a neutron star merger. This means that FIRST J141918.9+394036 likely marks a decades-old collision of two stars.

Within a few years, further observations of FIRST J141918.9+394036 will allow us to better distinguish between models and confirm its nature. And as we find more signals like this one, we can use these observations to further understand the origin and physics of neutron star mergers — potentially illuminating everything from the formation channel of binaries to the equation of state for neutron stars.

Citation

“FIRST J1419+3940 as the First Observed Radio Flare from a Neutron Star Merger,” K. H. Lee et al 2020 ApJL 902 L23. doi:10.3847/2041-8213/abbb8a

 

Source: American Astronomical Society - NOVA

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That young but already mature entirely self-made galaxy

Color image of the galaxy C1-23152 at redshift z=3.352, when the Universe was 1.8 billion years old. The image is the sum of 3 images at different wavelengths taken with the Hubble Space Telescope.  C1-23152 appears a regular spheroidal galaxy, its light profile matches exactly those of typical elliptical galaxies in the local Universe. Its stellar mass is about 200 billions of stars like sun and it is formed in less than 500 million years.

So young and already so mature: thanks to observations obtained at the Large Binocular Telescope, an international team of researchers coordinated by Paolo Saracco of the Istituto Nazionale di Astrofisica (INAF, Italy) was able to reconstruct the wild evolutionary history of an extremely massive galaxy that existed 12 billions years ago, when the Universe was only 1,8 billions years old, less than 13% of the present age. This galaxy, dubbed C1-23152, formed in "just" 500 million years, an incredibly short time to give rise to a mass of about 200 billion suns. To do so, it produced as many as 450 stars per year, more than one per day, a star formation rate almost 300 times higher than the current rate in our galaxy, the Milky Way.  The information obtained from this study will be fundamental for galaxy formation models for which the nature of objects such as C1-23152 is still difficult to account for.

The most massive galaxies that we observe in the Universe reach masses several hundred billion times that of the Sun and although they are numerically just one third of all galaxies, they contain more than 70% of the stars in the Universe. For this reason, how and how rapidly these galaxies formed are among the most debated questions of modern astrophysics. The current model of galaxy formation - the so-called hierarchical model - predicts that smaller galaxies formed earlier, while more massive systems formed later, through subsequent mergers of the pre-existing smaller galaxies. On the other hand, some of the properties of the most massive galaxies observed in the local Universe, such as the age of their stellar populations, suggest instead that they were formed at early epochs. Unfortunately, the variety of evolutionary phenomena that galaxies can undergo during their lives does not allow us to uniquely define, through studies conducted in the nearby Universe, the way in which they formed, leaving large margins of uncertainty. However, an answer to these questions can come from the study of the properties of massive galaxies in the early Universe, as close as possible to the time when they formed most of their mass.

Seventeen hours of spectroscopic observations with the Large Binocular Telescope (LBT) of the elliptical galaxy C1-23152, previously identified at a distance at which the Universe age was less than 13% of its current age, allowed Saracco’s team to reconstruct its evolutionary history. “The data show that the formation time of C1-23152, that is the time elapsed between the formation of the first stars from the pre-existing gas to the moment when the star formation has almost completely ceased, is less than 500 million of years” says Paolo Saracco, researcher at INAF in Milan and first author of the article published in The Astrophysical Journal. “Also, from the data collected with LBT we were able to establish that in this short time, corresponding to less than 4 hundredths of the age of the Universe, the galaxy formed a mass equal to about 200 billion stars like the Sun, that is about 450 suns per year. Our galaxy, the Milky Way, now forms no more than two a year", adds Danilo Marchesini, full professor at Tufts University and second author of the article. But that is not all. The large amount of information collected allowed the team to quantify for the first time in a galaxy so distant the abundance of chemical elements heavier than helium (the so-called metallicity): the stars of this galaxy have, surprisingly, a higher metallicity than that of the Sun, similar to that observed in the most massive galaxies in the Universe today.

Spectrum of galaxy C1-23152. The top panel shows the atmospheric transmission in the wavelength range of observations. In the middle panel the one-dimensional spectrum of galaxy C1-23152 is shown in the original form (dark-gray curve) and smoothed by a boxcar filter over three pixels (black curve) corresponding to the instrumental resolution. The main absorption and emission lines are marked by solid and dashed lines, respectively. The red curve is the best-fitting composite model obtained with STARLIGHT. The shaded gray regions are those masked in the fitting because of bad sky transmission or the presence of emission lines. For comparison, the bottom panel shows the observed spectrum of a typical post-starburst galaxy in the local Universe selected from the Sloan Digital Sky Survey (SDSS).

“These observations showed that the formation of the most massive galaxies in the Universe can occur extremely quickly, through an extremely intense star formation process in the early Universe, as for C1-23152", underlines Francesco La Barbera, researcher at INAF in Naples, in the team that conducted the study. "Understanding whether the scenario that describes the formation of C1-23152 is a particular case or whether, on the contrary, it is what happens for most of the most massive galaxies in the Universe is of fundamental importance since this would require a profound revision of the galaxy formation models”, adds Adriana Gargiulo, also a researcher at INAF in Milan and co-author of the study.

Likely formation scenario of massive elliptical galaxies like C1-23152. Massive primordial gas clouds, falling in the same region under the effect of gravitational force, collide triggering violent and massive star formation processes. The starburst phase is expected to last few hundreds of million years during which hundreds to thousands stars per year are formed, as for C1-23152. The resulting massive elliptical galaxy will then evolve with time, possibly experiencing different evolutionary phenomena. 

The formation of stellar masses as high as for C1-23152 requires both high masses of gas to convert into stars and particular physical conditions. A possible scenario hypothesized by the researchers is that massive primordial gas clouds, falling under the effect of gravitational force in the same region, collide, triggering violent and massive star formation processes. From the observational point of view, the precursors of the most massive galaxies could therefore be remote galaxies with a very high rate of star formation.

This image shows an example of starburst galaxies forming about a thousand of stars per year at the time of observation. This phase is most likely the formation phase of massive galaxies in the early Universe, like C1-23152.

"To test our hypotheses, the observations that the next generation of instrumentations will allow us to carry out will be decisive, in particular the James Webb Space Telescope (JWST) which will be launched in orbit at the end of 2021, and the Extremely Large Telescope (ELT) the largest ground-based telescope ever built, with a main mirror of 39 meters in diameter, which will be operational in 2026”, concludes Saracco.

Science Contacts:

• Paolo Saracco, paolo.saracco@inaf.it
• Danilo Marchesini, danilo.marchesini@tufts.edu
• Francesco La Barbera, francesco.labarbera@inaf.it
• Adriana Gargiulo, adriana.gargiulo@inaf.it

INAF Press Release:     https://www.media.inaf.it/2020/12/10/galassia-vega/

Publication link:  https://arxiv.org/pdf/2011.04657.pdf

 

 Source:  Large Binocular Telescope Observatory

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Nugget Galaxies Cross in the Sky

The canonical Einstein Cross, the quadruply lensed quasar Q2237+0305, is seen in this Hubble image. A new study has found two additional Einstein Crosses created by the lensing of compact galaxies. [NASA, ESA, and STScI]. Hi-res image

Diagram illustrating how light from a distant source can be bent by a foreground object to produce four identical images of the source. Click to enlarge. [NASA/ESA/D. Player (STScI)]

 

Detection and confirmation of the Einstein crosses, KIDS J232940-34092 (top two rows) and KIDS J122456+005048 (bottom two rows), via the KiDS survey and the MUSE integral field spectrograph on the VLT. Click to enlarge. [Napolitano et al. 2020]. Hi-res image

Seeing quadruple? In a rare phenomenon, some distant objects can appear as four copies arranged in an “Einstein cross”. A new study has found two more of these unusual sights — with an unexpected twist.

Searching for Rare Crosses

Gravitational lensing — the bending of light by the gravity of massive astronomical objects — can do some pretty strange things. One of lensing’s more striking creations is the Einstein cross, a configuration of four images of a distant, compact source created by the gravitational pull of a foreground object (which is usually visible in the center of the four images).

The canonical example of this phenomenon is the Einstein Cross, a gravitationally lensed object called QSO 2237+0305, seen in the cover image above. In this case, as with the majority of known Einstein crosses, the background source is a distant quasar — the small and incredibly bright nucleus of an active galaxy. But other sources can be lensed into Einstein crosses as well, under the right circumstances.

In a new study led by Nicola Napolitano (Sun Yat-sen University Zhuhai Campus, China), a team of scientists presents confirmation of two new Einstein crosses discovered within the 1,000 square degrees imaged in the Kilo-Degree Survey using the Very Large Telescope (VLT) in Chile. Einstein crosses are unusual enough to begin with, but these two discoveries are especially rare: the lensed sources are not quasars. Instead, they’re entire galaxies.

Galaxies, but Bite-Size

When a distant galaxy is lensed by a foreground object, it’s commonly smeared out into an an arc or a ring; this is because galaxies are large, extended objects. But if a galaxy is compact enough, the entire galaxy can be lensed into quadruple images instead of a smeared-out ring. Such is the case with Napolitano and collaborators’ new discoveries, KIDS J232940-340922 and KIDS J122456+005048: they’re both quadruply lensed compact galaxies known as post-blue nuggets.

What’s a blue nugget? This adorable categorization applies to a type of galaxy found only in the early universe. Blue nuggets are extremely small, quite massive, and undergoing a violent burst of star formation that produces lots of large, bright, blue stars.

Blue nuggets are thought to be suddenly quenched — their star formation is cut off — early in their evolution. As their star population then evolves, these post-blue nuggets then transition into red nuggets, compact collections of red stars that are theorized to become the cores of today’s large elliptical galaxies.

A Bright Future

By spectroscopically following up their Einstein cross discoveries, Napolitano and collaborators show that the two sources are both very compact, massive galaxies with low specific star formation rates. Their properties are consistent with post-blue nuggets currently undergoing quenching — which means that these Einstein crosses are excellent sources to study to learn about galaxy evolution.

The authors predict that, with future observatories like the Vera Rubin Observatory, Euclid, or the China Space Station Telescope, we may be able to find many thousands of Einstein crosses like these. There’s a lot to learn ahead!

Citation

“Discovery of Two Einstein Crosses from Massive Post-blue Nugget Galaxies at z > 1 in KiDS,” N. R. Napolitano et al 2020 ApJL 904 L31. doi:10.3847/2041-8213/abc95ba

 

Source: American Astronomical Society - NOVA 

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Hubble Pins Down Weird Exoplanet with Far-Flung Orbit

This Hubble Space Telescope image shows the environment around double star HD 106906. The brilliant light from these stars is masked here to allow fainter features in the system to be seen. The stars' circumstellar disk is asymmetric and distorted, perhaps due to the gravitational tug of the wayward planet HD 106906 b, which is in a very large and elongated orbit. Credits: NASA, ESA, M. Nguyen (University of California, Berkeley), R. De Rosa (European Southern Observatory), and P. Kalas (University of California, Berkeley and SETI Institute). Hi-res image

This Hubble Space Telescope image shows one possible orbit (dashed ellipse) of the 11-Jupiter-mass exoplanet HD 106906 b. This remote world is widely separated from its host stars, whose brilliant light is masked here to allow the planet to be seen. The planet resides outside its system's circumstellar debris disk, which is akin to our own Kuiper Belt of small, icy bodies beyond Neptune. The disk itself is asymmetric and distorted, perhaps due to the gravitational tug of the wayward planet. Other points of light in the image are background stars. Credits: NASA, ESA, M. Nguyen (University of California, Berkeley), R. De Rosa (European Southern Observatory), and P. Kalas (University of California, Berkeley and SETI Institute). Hi-res image

A planet in an unlikely orbit around a double star 336 light-years away may offer a clue to a mystery much closer to home: a hypothesized, distant body in our solar system dubbed "Planet Nine."

This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disk. This disk is similar to our Kuiper Belt of small, icy bodies beyond Neptune. In our own solar system, the suspected Planet Nine would also lie far outside of the Kuiper Belt on a similarly strange orbit. Though the search for a Planet Nine continues, this exoplanet discovery is evidence that such oddball orbits are possible.

"This system draws a potentially unique comparison with our solar system," explained the paper's lead author, Meiji Nguyen of the University of California, Berkeley. "It's very widely separated from its host stars on an eccentric and highly misaligned orbit, just like the prediction for Planet Nine. This begs the question of how these planets formed and evolved to end up in their current configuration."

The system where this gas giant resides is only 15 million years old. This suggests that our Planet Nine — if it does exist — could have formed very early on in the evolution of our 4.6-billion-year-old solar system.

A extreme orbit 

The 11-Jupiter-mass exoplanet called HD 106906 b was discovered in 2013 with the Magellan Telescopes at the Las Campanas Observatory in the Atacama Desert of Chile. However, astronomers did not know anything about the planet's orbit. This required something only the Hubble Space Telescope could do: collect very accurate measurements of the vagabond's motion over 14 years with extraordinary precision. The team used data from the Hubble archive that provided evidence for this motion.

The exoplanet resides extremely far from its host pair of bright, young stars — more than 730 times the distance of Earth from the Sun, or nearly 6.8 billion miles. This wide separation made it enormously challenging to determine the 15,000-year-long orbit in such a relatively short time span of Hubble observations. The planet is creeping very slowly along its orbit, given the weak gravitational pull of its very distant parent stars.

The Hubble team was surprised to find that the remote world has an extreme orbit that is very misaligned, elongated and external to the debris disk that surrounds the exoplanet's twin host stars. The debris disk itself is very unusual-looking, perhaps due to the gravitational tug of the wayward planet.

The 11-Jupiter-mass exoplanet called HD 106906 b, shown in this artist's illustration, occupies an unlikely orbit around a double star 336 light-years away. It may be offering clues to something that might be much closer to home: a hypothesized distant member of our solar system dubbed "Planet Nine." This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disk. Credits: NASA, ESA, and M. Kornmesser (ESA/Hubble). Hi-res image

 

How did it get there? 

 

So how did the exoplanet arrive at such a distant and strangely inclined orbit? The prevailing theory is that it formed much closer to its stars, about three times the distance that Earth is from the Sun. But drag within the system's gas disk caused the planet's orbit to decay, forcing it to migrate inward toward its stellar pair. The gravitational effects from the whirling twin stars then kicked it out onto an eccentric orbit that almost threw it out of the system and into the void of interstellar space. Then a passing star from outside the system stabilized the exoplanet's orbit and prevented it from leaving its home system.

Using precise distance and motion measurements from the European Space Agency's Gaia survey satellite, candidate passing stars were identified in 2019 by team members Robert De Rosa of the European Southern Observatory in Santiago, Chile, and Paul Kalas of the University of California.

A messy disk 

This scenario for HD 106906 b’s bizarre orbit is similar in some ways to what may have caused the hypothetical Planet Nine to end up in the outer reaches of our own solar system, well beyond the orbit of the other planets and beyond the Kuiper Belt. Planet Nine could have formed in the inner solar system and been kicked out by interactions with Jupiter. However, Jupiter — the proverbial 800-pound gorilla in our solar system — would very likely have flung Planet Nine far beyond Pluto. Passing stars may have stabilized the orbit of the kicked-out planet by pushing the orbit path away from Jupiter and the other planets in the inner solar system.

"It's as if we have a time machine for our own planetary system going back 4.6 billion years to see what may have happened when our young solar system was dynamically active and everything was being jostled around and rearranged," said Kalas.

To date, astronomers only have circumstantial evidence for Planet Nine. They've found a cluster of small celestial bodies beyond Neptune that move in unusual orbits compared with the rest of the solar system. This configuration, some astronomers say, suggests these objects were shepherded together by the gravitational pull of a huge, unseen planet. An alternative theory is that there is not one giant perturbing planet, but instead the imbalance is due to the combined gravitational influence of multiple, much smaller objects. Another theory is that Planet Nine does not exist at all and the clustering of smaller bodies may be just a statistical anomaly.

A target for Webb Telescope

Scientists using NASA's upcoming James Webb Space Telescope plan to get data on HD 106906 b to understand the planet in detail. "One question you could ask is: Does the planet have its own debris system around it? Does it capture material every time it goes close to the host stars? And you'd be able to measure that with the thermal infrared data from Webb," said De Rosa. "Also, in terms of helping to understand the orbit, I think Webb would be useful for helping to confirm our result."

Because Webb is sensitive to smaller, Saturn-mass planets, it may be able to detect other exoplanets that have been ejected from this and other inner planetary systems. "With Webb, we can start to look for planets that are both a little bit older and a little bit fainter," explained Nguyen. The unique sensitivity and imaging capabilities of Webb will open up new possibilities for detecting and studying these unconventional planets and systems.

The team's findings appear in the December 10, 2020, edition of The Astronomical Journal.

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.

Media Contacts:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940
claire.andreoli@nasa.gov

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

Science Contacts:

Science Contacts:
Meiji Nguyen 
University of California, Berkeley, California 
meiji274@berkeley.edu

Robert De Rosa 
European Southern Observatory, Santiago, Chile 
rderosa@eso.org

Paul Kalas
University of California, Berkeley, California
kalas@berkeley.edu

Editor: Lynn Jenner

Source: NASA/Solar System and Beyond

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Hubble Captures Unprecedented Fading of Stingray Nebula

Hen 3-1357/Stingray Nebula

Credit:  NASA, ESA, B. Balick (University of Washington), M. Guerrero (Instituto de Astrofísica de Andalucía), and G. Ramos-Larios (Universidad de Guadalajara)

Release Images /  Release Videos

 Astronomers have caught a rare look at a rapidly fading shroud of gas around an aging star. Archival data from NASA’s Hubble Space Telescope reveal that the nebula Hen 3-1357, nicknamed the Stingray nebula, has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceeding rare, say researchers.

Images captured by Hubble in 2016, when compared to Hubble images taken in 1996, show a nebula that has drastically dimmed in brightness and changed shape. Bright blue fluorescent tendrils and filaments of gas toward the center of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the vast universe.

“This is very, very dramatic, and very weird,” said team member Martín A. Guerrero of the Instituto de Astrofísica de Andalucía in Granada, Spain. “What we’re witnessing is a nebula’s evolution in real-time. In a span of years, we see variations in the nebula. We have not seen that before with the clarity we get with this view.”

Researchers discovered unprecedented changes in the light emitted by glowing nitrogen, hydrogen and oxygen being blasted off by the dying star at the center of the nebula. The oxygen emission, in particular, dropped in brightness by a factor of nearly 1,000 between 1996 and 2016.

“Changes in nebulae have been seen before, but what we have here are changes in the fundamental structure of the nebula,” said Bruce Balick of the University of Washington Seattle, leader of the new research. “In most studies, the nebula usually gets bigger. Here, it’s fundamentally changing its shape and getting fainter, and doing so on an unprecedented time scale. Moreover, to our surprise, it’s not growing any larger. Indeed, the once-bright inner elliptical ring seems to be shrinking as it fades.”

Ground-based observations of other planetary nebulae have shown hints of changes in brightness over time, but those speculations haven’t been confirmed until now. Only Hubble can resolve the changes in structure in this tiny nebula. The new paper examines every image of the Stingray nebula from Hubble’s archives.

“Because of Hubble’s optical stability, we are very, very confident that this nebula is changing in brightness with time,” added Guerrero. “This is something that can only be confirmed with Hubble’s visual acuity.”

The researchers note the nebula’s rapid changes are a response to its central star, SAO 244567, expanding due to a temperature drop, and in turn emitting less ionizing radiation.

A 2016 study by Nicole Reindl now of the University of Potsdam, Germany, and a team of international researchers, also using Hubble data, noted the star at the center of the Stingray nebula, SAO 244567, is special in its own right.

Observations from 1971 to 2002 showed the temperature of the star skyrocketing from less than 40,000 to 108,000 degrees Fahrenheit, more than ten times hotter than the surface of our Sun. Now, Reindl and her research team has shown that SAO 245567 is cooling. Reindl speculates the temperature jump was caused by a brief flash of helium fusion that occurred in a shell around the core of the central star. Recently, the star appears to be backstepping into its early stage of stellar evolution.

“We’re very lucky to observe it just in that moment,” said Reindl. “During such a helium shell flash, it evolves very quickly and that implies short evolutionary timescales so we can’t usually see how these stars evolve. We just happened to be there at the right time to have caught that.”

The team studying the rapid fading of the Stingray nebula can only speculate at this time what’s in store for the future of this young nebula. At its present rates of fading, it’s estimated the nebula will barely be detectable in 20 or 30 years.

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.

Source: HubbleSite

Related Links

• The science paper by B. Balick et al.
• NASA's Hubble Telescope 
• ESA/Hubble's Release

Contacts

Hannah Braun / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4244 / 410-338-4514
hbraun@stsci.edu / villard@stsci.edu

Bruce Balick
University of Washington, Seattle, Washington
balick@uw.edu

Martín A. Guerrero
Instituto de Astrofísica de Andalucía, Granada, Spain
mar@iaa.es

Gerardo Ramos-Larios
Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
gerardo.astro@gmail.com

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A three-dimensional view of the Milky Way

Colourful variety: The section shows interstellar clouds in a small area of about 5% of the total SEDIGISM mapping; each of these clouds is coloured differently. The small picture in the upper left diagrams the course of the spiral arms in the Milky Way. The grey region marks the complete area of the SEDIGISM mapping. In this illustration, the direction of the sector is light blue. Ana Duarte-Cabral, Alex Pettitt, and James Urquhart

The Apex telescope makes it possible to observe molecular clouds and star births in the galactic plane

December 03, 2020 In our Milky Way, there are about 200 billion suns as well as large quantities of gas, some of which serves as raw material for star births. The gas collects in compact lumps but also appears as extended molecular clouds. Astronomers have used the Apex sub-millimetre telescope in Chile to look deep into the galactic plane and measure the interstellar medium. They studied the distribution of the cold molecular gas in the inner region of the Milky Way with unprecedented accuracy. The researchers catalogued more than 10,000 interstellar clouds. They found out that currently only about 10% of them contain stars. The project is called SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium) and covers an area of 84 square degrees in the southern sky.

The mapping contains data from 2013 to 2017, which was collected by the 12-metre Apex telescope in the Chilean Andes. “With the publication of this most detailed map of cold molecular clouds in the Milky Way to date, a long-term observation project is now coming to fruition”, says Frederic Schuller from the Max Planck Institute for Radio Astronomy, the project leader of SEDIGISM.

Scientists have been able to observe the southern part of the inner Milky Way with an angular resolution of 30 arcseconds; this corresponds to ¹⁄₆₀ of the apparent diameter of the full moon in the Earth’s sky. They have also gained valuable information on structure, distance, and velocity for all galactic molecular clouds in about two thirds of the inner disc of the Milky Way.

The researchers observed the spectral lines of the carbon monoxide molecule – including the rare isotopes ¹³CO and C¹⁸O – and deduced the mass and three-dimensional distribution of cold and dense molecular gas in the interstellar medium. Various structures such as filaments and recesses were found; these are the result of different physical effects.

Molecular clouds contain the raw material from which new stars are formed. The mapping of these clouds is therefore necessary to determine important parameters such as the efficiency of star formation in the Milky Way. Structures and physical conditions within the clouds provide the fundamental basis for the theories of star formation. It is therefore important to spatially resolve the individual clouds and distinguish them from each other.

One key to the success was the 12-metre Apex telescope with its highly accurate surface and one of the world’s best locations for sub-millimetre astronomy. The instrument is located at an altitude of 5100 meters on the Chajnantor Plain in the Chilean Atacama Desert. Here, there is extremely low water vapour content and thus excellent transparency of the atmosphere.

The new data complement a series of mappings of the galactic plane produced in the mid to far infra-red wavelength range over the past decade. This was done with space telescopes such as the Spitzer, Herschel, and – for longer wavelengths – the Apex itself. However, these projects lacked the speed information that SEDIGISM has now provided. The re-analysis of the data allows a more detailed study of star formation – and thus of the structure and dynamics of the Milky Way itself.

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Contact

 

Dr. Norbert Junkes

Press and public relations

Phone:+49 2 28525-399

Max Planck Institute for Radio Astronomy, Bonn

Dr. Friedrich Wyrowski

Phone:+49 228 525381

Max Planck Institute for Radio Astronomy, Bonn

Dr. Dario Colombo

Phone:+49 228 525-196

Max Planck Institute for Radio Astronomy, Bonn

 

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Original Publication

 

1. F. Schuller et al.

The SEDIGISM survey: first data release and overview of the Galactic structure

Monthly Notices of the Royal Astronomical Society, 26. November 2020

DOI

 

2. A. Duarte-Cabral et al.

The SEDIGISM survey: Molecular clouds in the inner Galaxy

Monthly Notices of the Royal Astronomical Society, 26. November 2020

DOI

 

3. J. S. Urquhart et al.

SEDIGISM-ATLASGAL: Dense Gas Fraction and Star Formation Efficiency across the Galactic Disk

Monthly Notices of the Royal Astronomical Society, 26. November 2020

DOI 

 Source:  Max Planck Institute for Radio Astronomy

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HETDEX Project On Track to Probe Dark Energy

Pinwheel Galaxy from VIRUS (with labels)
Credit: G. Zeimann/HETDEX Collaboration
M101_with_labels.png

Click to access a video of the Pinwheel Galaxy (M101) that demonstrates the power of the VIRUS instrument designed for the HETDEX survey. Includes captions and access to all images for this release 

FORT DAVIS, Texas — Three years into its quest to reveal the nature of dark energy, the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is on track to complete the largest map of the cosmos ever. The team will create a three-dimensional map of 2.5 million galaxies that will help astronomers understand how and why the expansion of the universe is speeding up over time.

“HETDEX represents the coming together of many astronomers and institutions to conduct the first major study of how dark energy changes over time,” said Taft Armandroff, director of The University of Texas at Austin’s McDonald Observatory.

The survey began in January 2017 on the 10-meter Hobby-Eberly Telescope (HET) at McDonald Observatory. Today, the survey is 38% complete. Data reduction and analysis are continuing.

“HETDEX has arrived,” said astronomer Karl Gebhardt. “We’re over a third of the way through our program now, and we have this fantastic data set that we’re going to use to measure the dark energy evolution.”

The survey works by aiming the telescope at two regions of the sky near the Big Dipper and Orion. For each pointing, the telescope records around 32,000 spectra, capturing the cosmic fingerprint of the light from every object within the telescope’s field of view.

“It’s actually a little mind-blowing, how much information is captured in this,” said team member Gary Hill.

These spectra are recorded via 32,000 optical fibers that feed into more than 100 instruments working together as one. This assembly is called VIRUS, the Visible Integral-field Replicable Unit Spectrograph. It’s a massive machine made up of dozens of copies of an instrument working together for efficiency. VIRUS was designed and built especially for HETDEX.

This makes VIRUS one of the most advanced astronomical instruments in the world. Building it “was quite a task to orchestrate,” Hill said, noting that the project has taken a decade to reach fruition. “It’s the largest on many measures,” he said, noting that it has the most optical fibers, as well as having as much detector area as the largest astronomical cameras. It’s also an extremely large instrument, taking up much of the room inside the telescope dome.

HETDEX is a blind survey, meaning that rather than pointing at specific targets, it records everything over a specific patch of sky. Then scientists go through the data to sift out objects they want to study.

Team member Phillip MacQueen has worked on the technical challenges of delivering VIRUS to the HETDEX specifications. He reminds us that map making in astronomy started with the first people who looked at the sky.

“VIRUS is an astronomical cartographer’s delight,” MacQueen said. “It does much more than map where objects are in two dimensions on the sky. HETDEX is using VIRUS to map where objects lie in a truly enormous volume of the universe, both within our galaxy and far beyond it.”

To make the map needed for the dark energy project, they are combing through a billion spectra looking for examples of a specific type of galaxy. These galaxies range in distances from 10 billion to 11.7 billion light-years away, so they represent an epoch when the universe was only a few billion years old. Their spectra carry information about how fast the galaxies are moving away from us as a result of the expansion of the universe. That will allow astronomers to determine how the rate at which the universe expands has changed over the eons, which is key to determining the nature of dark energy.

The HETDEX team expects to complete their observations by December 2023. In total, the completed survey will include 1 billion spectra, “the largest ever spectral survey by far,” Gebhardt said. These data are processed and stored at UT Austin’s Texas Advanced Computing Center (TACC), one of the top supercomputing centers in the world.

Erin Mentuch Cooper is the project’s data manager. “We’re very fortunate to have access” to TACC, she said, explaining that during the summer, a TACC supercomputer processed all of the HETDEX data now in hand in two weeks. It would have taken a single computer 10 years, she said.

Meanwhile, many astronomers are using the data already collected to attack a number of other astronomical mysteries. Several are on the verge of publishing their research.

Among them is UT professor Keith Hawkins. He has made use of the survey’s spectra of about 100,000 stars in our own Milky Way galaxy. Though these stars were not the main quarry for HETDEX, they were captured by the blind survey. “As my grandfather used to say, ‘One man’s trash is another man’s treasure,’” he said.

Hawkins is using these spectra to study the stars’ contents, sizes, temperatures and motions to trace how the different parts of our galaxy came together. His research paper on this work will be published soon. Other astronomers are preparing to publish research on white dwarfs and nearby galaxies for which they used HETDEX data.

HETDEX is a large international collaboration. The project is led by The University of Texas at Austin McDonald Observatory and Department of Astronomy, with participation from Penn State University; Ludwig Maximilians University, Munich; the Max Planck Institute for Extraterrestrial Physics; the Institute for Astrophysics, Gottingen; the Leibniz Institute for Astrophysics, Potsdam; Texas A&M University; The University of Oxford; the Max Planck Institute for Astrophysics; The University of Tokyo; and the Missouri University of Science and Technology.

In addition to institutional support, HETDEX is funded by the National Science Foundation (grant AST-0926815), the State of Texas, the U.S. Air Force (AFRL FA9451-04-2-0355), and generous support from private individuals and foundations.

Source:  The University of Texas McDonald Observatory/News

Media Contact:

Rebecca Johnson, Communications Mgr.
McDonald Observatory
The University of Texas at Austin
512-475-6763

Additional Contacts:

Dr. Taft Armandroff, Director
McDonald Observatory
The University of Texas at Austin
512-471-3300

Dr. Karl Gebhardt, Herman and Joan Suit Professor of Astrophysics
Department of Astronomy
The University of Texas at Austin
512-590-5206

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