Thursday, March 31, 2022

A Record Broken: Hubble Finds the Most Distant Star Ever Seen

Hubble Finds the Most Distant Star Ever Seen

The Sunrise Arc Galaxy with Lensed Star Earendel (Annotated)



Videos

Space Sparks Episode 10: Hubble Finds the Most Distant Star Ever Seen
Space Sparks Episode 10: Hubble Finds the Most Distant Star Ever Seen



The NASA/ESA Hubble Space Telescope has established an extraordinary new benchmark: detecting the light of a star that existed within the first billion years after the Universe’s birth in the Big Bang (at a redshift of 6.2) — the most distant individual star ever seen. This sets up a major target for the NASA/ESA/CSA James Webb Space Telescope in its first year.

This find is a huge leap back in time compared to the previous single-star record holder; detected by Hubble in 2018. That star existed when the universe was about 4 billion years old, or 30 percent of its current age, at a time that astronomers refer to as “redshift 1.5.” Scientists use the word “redshift” because as the Universe expands, light from distant objects is stretched or “shifted” to longer, redder wavelengths as it travels toward us.

But the newly detected star is so far away that its light has taken 12.9 billion years to reach Earth, appearing to us as it did when the universe was only 7 percent of its current age, at redshift 6.2. The smallest objects previously seen at such a great distance are clusters of stars, embedded inside early galaxies.

We almost didn’t believe it at first, it was so much farther than the previous most distant, highest redshift star,” said astronomer Brian Welch of the Johns Hopkins University in Baltimore, lead author of the paper describing the discovery, which is published in the journal Nature. The discovery was made from data collected during Hubble’s RELICS (Reionization Lensing Cluster Survey) program, led by co-author Dan Coe at the Space Telescope Science Institute (STScI).

Normally at these distances, entire galaxies look like small smudges, the light from millions of stars blending together,” said Welch. “The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc.” After studying the galaxy in detail, Welch determined that one feature is an extremely magnified star that he called Earendel, which means “morning star” in Old English. The discovery holds the promise of opening up an uncharted era of very early star formation.

Earendel existed so long ago that it may not have had all the same raw materials as the stars around us today,” Welch explained. “Studying Earendel will be a window onto an era of the Universe that we are unfamiliar with, but that led to everything we do know. It’s like we’ve been reading a really interesting book, but we started with the second chapter, and now we will have a chance to see how it all got started,” Welch said.

There’s a long-standing theoretical prediction that stars that form solely out of the elements that were forged shortly after the Big Bang — hydrogen, helium and trace amounts of lithium — should be more massive than the stars that form today,” added team member Erik Zackrisson, of the Department of Physics and Astronomy at Uppsala University in Sweden. “These primordial stars, known as Population III stars, have so far eluded observers, but could be rendered detectable if subject to very high magnification by gravitational lensing, as in the case of the Earendel object.

The research team estimates that Earendel is at least 50 times the mass of our Sun and millions of times as bright, rivalling the most massive stars known. But even such a brilliant, very high-mass star would be impossible to see at such a great distance without the aid of natural magnification by a huge galaxy cluster, in this case known as WHL0137-08, sitting between us and Earendel. The mass of the galaxy cluster warps the fabric of space, creating a powerful natural magnifying glass that distorts and greatly amplifies the light from distant objects behind it.

Thanks to the rare alignment with the magnifying galaxy cluster, the star Earendel appears directly on, or extremely close to, a ripple in the fabric of space. This ripple, which is known in optics as a “caustic,” provides maximum magnification and brightening. The effect is analogous to the rippled surface of a swimming pool creating patterns of bright light on the bottom of the pool on a sunny day. The ripples on the surface act as lenses and focus sunlight to maximum brightness on the pool floor.

This caustic causes the star Earendel to pop out from the general glow of its home galaxy. Its brightness is magnified a thousandfold or more. At this point astronomers are not able to determine whether Earendel is a binary star, but most massive stars do have at least one smaller companion star.

Astronomers expect that Earendel will remain highly magnified for years to come. It will be observed by the NASA/ESA/CSA James Webb Space Telescope [1]  later in 2022 [2]. Webb’s high sensitivity to infrared light is needed to learn more about Earendel, because its light is stretched (redshifted) to longer infrared wavelengths by the expansion of the Universe.

Webb’s images and spectra will allow us to confirm that Earendel is indeed a star, and to constrain its age, temperature, mass and radius,” explained team member Jose Maria Diego of the Instituto de Física de Cantabria in Spain. “Combining observations from Hubble and Webb will allow us to also learn about microlenses in the galaxy cluster, which could include exotic objects like primordial black holes.

Earendel’s composition will be of great interest to astronomers, because it formed before the Universe was filled with the heavy elements produced by successive generations of massive stars. If follow-up studies find that Earendel is only made of primordial hydrogen and helium, it would be the first evidence for the legendary Population III stars, which are hypothesised to be the very first stars to form after the Big Bang. While the probability is small, Welch admits it is enticing all the same.

With Webb, we may see stars even more distant than Earendel, which would be incredibly exciting,” Welch said. “We’ll go as far back as we can. I would love to see Webb break Earendel’s distance record.



Notes 
 
[1] Launched in December 2021 on an Ariane 5 rocket from Europe’s Spaceport in French Guiana, Webb is designed and built to offer scientists the capabilities needed to push the frontiers of knowledge in many areas of astronomy. This includes research on our own Solar System, the formation of stars and planets (including planets outside our Solar System — exoplanets), and on how galaxies are formed and evolve, in ways never before possible. The James Webb Space Telescope is an international project led by NASA in partnership with ESA and the Canadian Space Agency. You can stay up to date on ESA/Webb updates here.

[2] Earendel will be observed with the James Webb Space Telescope as part of the observing programme #2282.




More information

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

The international team of astronomers who carried out this study consists of B. Welch, D. Coe, J. M. Diego, A. Zitrin, E. Zackrisson, P. Dimauro, Y. Jimenez-Teja, P. Kelly, G. Mahler, M. Oguri, F. X. Timmes, R. Windhorst, M. Florian, S. E. de Mink, R. J. Avila, J. Anderson, L. Bradley, K. Sharon, A. Vikaeus, S. McCandliss, M. Bradac, J. Rigby, B. Frye, S. Toft, V. Strait, M. Trenti, S. Sharma. F. Andrade-Santos, T. Broadhurst. Image credit: NASA, ESA, B. Welch (JHU), D. Coe (STScI), A. Pagan (STScI)




Links



Contacts

Brian Welch
Johns Hopkins University
Baltimore, USA
Email:
bwelch7@jhu.edu

Bethany Downer
ESA/Hubble Chief Science Communications Officer
Email:
Bethany.Downer@esahubble.org

Monday, March 28, 2022

Hey DUDE: Mysterious Death of Carbon Star Plays Out Like Six-Ring Circus


Scientists have observed, for the first time, the mysterious death throes of a carbon-rich asymptotic branch star (AGB). V Hydrae’s final act is characterized by the mass ejection of matter into space, resulting in the slow expansion of six rings and the formation of two hourglass-shaped structures shown here in this artist’s conception. Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO/AUI/NSF).
Hi-Res File


The carbon-rich star V Hydrae is in its final act, and so far, its death has proved magnificent and violent. Scientists studying the star have discovered six outflowing rings (shown here in composite), and other structures created by the explosive mass ejection of matter into space. Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO/AUI/NSF).
Hi-Res File


Scientists studying the dying carbon-rich star V Hya have discovered six slowly expanding rings forming as the star expels its matter. Shown here in composite, these outflowing rings and the diffuse arc structure of the sixth ring are moderately visible in the 12CO carbon isotope emission line, and become well-defined in views of the 13CO carbon isotopes. These rings are part of a previously unknown story about the death of stars, and are helping scientists to unravel what happens in the “final act.” Credit: ALMA (ESO/NAOJ/NRAO)/S. Dagnello (NRAO/AUI/NSF).
Hi-Res File


V Hydrae is a carbon-rich star located 1,300 light-years away in the constellation Hydra. It is the subject of recent observations revealing the violent deaths of stars, which include, in the case of V Hya, explosive ejections of plasma into space that shape the structural environment around the star. Credit: IAU and Sky & Telescope.
Hi-Res File

Scientists studying V Hydrae (V Hya) have witnessed the star’s mysterious death throes in unprecedented detail. Using the Atacama Large Millimeter/submillimeter Array (ALMA) and data from the Hubble Space Telescope (HST), the team discovered six slowly-expanding rings and two hourglass-shaped structures caused by the high-speed ejection of matter out into space. The results of the study are published in The Astrophysical Journal.

V Hya is a carbon-rich asymptotic giant branch (AGB) star located approximately 1,300 light-years from Earth in the constellation Hydra. More than 90-percent of stars with a mass equal to or greater than the Sun evolve into AGB stars as the fuel required to power nuclear processes is stripped away. Among these millions of stars, V Hya has been of particular interest to scientists due to its so-far unique behaviors and features, including extreme-scale plasma eruptions that happen roughly every 8.5 years and the presence of a nearly invisible companion star that contributes to V Hya’s explosive behavior.

“Our study dramatically confirms that the traditional model of how AGB stars die—through the mass ejection of fuel via a slow, relatively steady, spherical wind over 100,000 years or more—is at best, incomplete, or at worst, incorrect,” said Raghvendra Sahai, an astronomer at NASA’s Jet Propulsion Laboratory, and the principal researcher on the study. “It is very likely that a close stellar or substellar companion plays a significant role in their deaths, and understanding the physics of binary interactions is both important across astrophysics and one of its greatest challenges. In the case of V Hya, the combination of a nearby and a hypothetical distant companion star is responsible, at least to some degree, for the presence of its six rings, and the high-speed outflows that are causing the star’s miraculous death.”

Mark Morris, an astronomer at UCLA and a co-author on the research added, “V Hydra has been caught in the process of shedding its atmosphere—ultimately most of its mass—which is something that most late-stage red giant stars do. Much to our surprise, we have found that the matter, in this case, is being expelled as a series of outflowing rings. This is the first and only time that anybody has seen that the gas being ejected from an AGB star can be flowing out in the form of a series of expanding ‘smoke rings.’”

The six rings have expanded outward from V Hya over the course of roughly 2,100 years, adding matter to and driving the growth of a high-density flared and warped disk-like structure around the star. The team has dubbed this structure the DUDE, or Disk Undergoing Dynamical Expansion.

“The end state of stellar evolution—when stars undergo the transition from being red giants to ending up as white dwarf stellar remnants—is a complex process that is not well understood,” said Morris. “The discovery that this process can involve the ejections of rings of gas, simultaneous with the production of high-speed, intermittent jets of material, brings a new and fascinating wrinkle to our exploration of how stars die.”

Sahai added, “V Hya is in the brief but critical transition phase that does not last very long, and it is difficult to find stars in this phase, or rather ‘catch them in the act. We got lucky and were able to image all of the different mass-loss phenomena in V Hya to better understand how dying stars lose mass at the end of their lives.”

In addition to a full set of expanding rings and a warped disk, V Hya’s final act features two hourglass-shaped structures—and an additional jet-like structure—that are expanding at high speeds of more than half a million miles per hour (240 km/s). Large hourglass structures have been observed previously in planetary nebulae, including MyCn 18 —also known as the Engraved Hourglass Nebula—a young emission nebula located roughly 8,000 light-years from Earth in the southern constellation of Musca, and the more well-known Southern Crab Nebula, an emission nebula located roughly 7,000 light-years from Earth in the southern constellation Centaurus.

Sahai said, “We first observed the presence of very fast outflows in 1981. Then, in 2022, we found a jet-like flow consisting of compact plasma blobs ejected at high speeds from V Hya. And now, our discovery of wide-angle outflows in V Hya connects the dots, revealing how all these structures can be created during the evolutionary phase that this extra-luminous red giant star is now in.”

Due to both the distance and the density of the dust surrounding the star, studying V Hya required a unique instrument with the power to clearly see matter that is both very far away and also difficult or impossible to detect with most optical telescopes. The team enlisted ALMA’s Band 6 (1.23mm) and Band 7 (.85mm) receivers, which revealed the star’s multiple rings and outflows in stark clarity.

“The processes taking place at the end stages of low mass stars, and during the AGB phase in particular, have long fascinated astronomers and have been challenging to understand,” said Joe Pesce, an astronomer and NSF program officer for NRAO/ALMA. “The capabilities and resolution of ALMA are finally allowing us to witness these events with the extraordinary detail necessary to provide some answers and enhance our understanding of an event that happens to most of the stars in the Universe.”

Sahai added that the incorporation of infrared, optical, and ultraviolet data into the study created a complete multi-wavelength picture of what might be one of the greatest shows in the Milky Way, at least for astronomers. “Each time we observe V Hya with new observational capabilities, it becomes more and more like a circus, characterized by an even bigger variety of impressive feats. V Hydrae has impressed us with its multiple rings and acts, and because our own Sun may one day experience a similar fate, it has us at rapt attention.”



Research
  • “The rapidly evolving AGB star, V Hya: ALMA finds a multi-ring circus with high velocity outflow,” Sahai et al, (2022), The Astrophysical Journal, preprint: arXiv:2202.09335

Resources

  • “Discovery of very high velocity outflow in V Hydra – Wind from an accretion disk in a binary?” Sahai, R. & Wannier, P. G. (1988), Astronomy & Astrophysics, ADS: 1988A&A…201L…9S
  • “V Hydrae: the missing link between spherical red giants and bipolar planetary nebulae? Radio observations of the molecular envelope,” Kahane et al (1996), Astronomy & Astrophysics, ADS: 1996A&A…314..871K
  • “A collimated, high-speed outflow from the dying star V Hydrae,” Sahai et al (2003), Nature, 426, 261, doi.org/10.1038/nature02086
  • “High-velocity bipolar outflow and disklike envelope in the carbon star V Hydrae,” Hirano et al (2004), The Astrophysical Journal, doi: 10.1086/424382 “High-Speed Bullet Ejections during the AGB to Planetary Nebula Transition: HST Observations of the Carbon Star, V Hydrae,” Sahai, R., Scibelli, S., & Morris, M.R. (2016), The Astrophysical Journal, doi.org/10.3847/0004-637x/827/2/92

About ALMA

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.


Media Contact:

Amy C. Oliver
Public Information Officer, ALMA-North America

aoliver@nrao.edu
+1-434-242-9584

Source: National Radio Astronomy Observatory (NRAO)/News


Thursday, March 24, 2022

Astronomers Reveal Remarkable Simulations of the Early Universe, from the Dark Ages through First Light

Gas in the universe as it goes through the reionization process.
Thesan Collaboration

Low Resolution Image


Still image from a Thesan simulation showing the universe 251 million years after the Big Bang. The orange halos represent the burst of radiation, or light, outpouring from early galaxies. Thesan Collaboration
 
Cambridge, MA -- It looks like fireflies flickering in the darkness. Slowly, more and more amass, lighting up the screen in large chunks and clusters.

But this is not a video about insects. It's a simulation of the early universe, a time after the Big Bang when the cosmos transformed from a place of utter darkness to a radiant, light-filled environment.


 
The stunning video is part of a large suite of simulations described in a series of three papers accepted to the Monthly Notices of the Royal Astronomical Society. Created by researchers at the Center for Astrophysics | Harvard & Smithsonian, the Massachusetts Institute of Technology and the Max Planck Institute for Astrophysics, the simulations represent a monumental advancement in simulating the formation of the first galaxies and reionization — the process by which neutral hydrogen atoms in space were transformed into positively charged, or ionized, hydrogen, allowing light to spread throughout the universe.

The simulated period, known as the epoch of reionization, took place some 13 billion years ago and was challenging to reconstruct, as it involves immensely complicated, chaotic interactions, including those between gravity, gas and radiation, or light.

"Most astronomers don't have labs to conduct experiments in. The scales of space and time are too large, so the only way we can do experiments is on computers," explains Rahul Kannan, an astrophysicist at the Center for Astrophysics and the lead author of the first paper in the series. "We are able to take basic physics equations and governing theoretical models to simulate what happened in the early universe."

The team's simulations — named Thesan after the Etruscan goddess of dawn — resolve interactions in the early universe with the highest detail and over the largest volume of any previous simulation. Physics in the early universe are captured down to scales that are a million times smaller than the simulated regions, providing unprecedented detail on properties of early galaxies and how light from these galaxies impacted gas.

The team accomplishes this by combining a realistic model of galaxy formation with a new algorithm that tracks how light interacts with gas, along with a model for cosmic dust.

With Thesan, researchers can simulate a piece of our universe spanning over 300 million light years across. The team can run the simulation forward in time to track and visualize the first appearance and evolution of hundreds of thousands of galaxies within this space, beginning around 400,000 years after the Big Bang, and through the first billion years.

The simulations reveal a gradual change in the universe from complete darkness to light.

"It's a bit like water in ice cube trays; when you put it in the freezer, it does take time, but after a while it starts to freeze on the edges and then slowly creeps in," says study co-author Aaron Smith, a NASA Einstein Fellow in MIT's Kavli Institute for Astrophysics and Space Research. "This was the same situation in the early universe — it was a neutral, dark cosmos that became bright and ionized as light began to emerge from the first galaxies."

The simulations were created to prepare for observations from the James Webb Space Telescope (JWST), which will be able to peer further back in time — approximately 13.5 billion years — than predecessors like the Hubble Space Telescope.

"A lot of telescopes coming online, like the JWST, are specifically designed to study this epoch," Kannan says. “That's where our simulations come in; they are going to help us interpret real observations of this period and understand what we’re seeing."

Real telescope observations and data will soon be compared to Thesan simulations, the team explains.

"And thats the interesting part," says study co-author Mark Vogelsberger, an associate professor of physics at MIT. "Either our Thesan simulations and model will agree with what JWST finds, which would confirm our picture of the universe, or there will be a significant disagreement showing that our understanding of the early universe is wrong."

The team, however, won't know how various aspects of their model fares until the first observations roll in, which will cover a wide range of topics, including galaxy properties and the absorption and escape of light in the early universe.

"We have developed simulations based on what we know," Kannan says. "But while the scientific community has learned a lot in recent years, there is still quite a bit of uncertainty, especially in these early times when the universe was very young."

The simulations were created using one of the world's largest supercomputers, the SuperMUC-NG, over the course of 30 million CPU-hours. The same simulations would have required more than 3,500 years to complete on a normal computer.

Additional scientists who make up the Thesan team are Lars Hernquist of the CfA; and Enrico Garaldi, Ruediger Pakmor and Volker Springel of the Max Planck Institute for Astrophysics.




About the Center for Astrophysics | Harvard & Smithsonian

The Center for Astrophysics | Harvard & Smithsonian is a collaboration between Harvard and the Smithsonian designed to ask—and ultimately answer—humanity's greatest unresolved questions about the nature of the universe. The Center for Astrophysics is headquartered in Cambridge, MA, with research facilities across the U.S. and around the world.

Media Contact:
 
Nadia Whitehead
Public Affairs Officer
Center for Astrophysics | Harvard & Smithsonian

nadia.whitehead@cfa.harvard.edu
617-721-7371
 

Wednesday, March 23, 2022

Strong-Arming a Galaxy


The overdeveloped spiral arm of the galaxy NGC 772, which was created by tidal interactions with an unruly neighbor, dominates this observation made by astronomers using the Gemini North telescope located near the summit of Maunakea in Hawai‘i. International Gemini Observatory/NOIRLab/NSF/AURA. Image processing: T.A. Rector (University of Alaska Anchorage), J. Miller (Gemini Observatory/NSF's NOIRLab), M. Zamani & D. de Martin.
download Large JPEG


This video zooms into the galaxy NGC 772. Credit: International Gemini Observatory/NOIRLab/NSF/AURA. Image processing: T.A. Rector (University of Alaska Anchorage), J. Miller (Gemini Observatory/NSF's NOIRLab), M. Zamani & D. de Martin. Music: Zero-project - Through the Looking Glass (
zero-project.gr)

The pumped-up arm of the lopsided spiral galaxy NGC 772 dominates this image from the international Gemini Observatory, a Program of NSF's NOIRLab.

The overdeveloped spiral arm of the galaxy NGC 772, which was created by tidal interactions with an unruly neighbor, dominates this observation made by astronomers using the Gemini North telescope located near the summit of Maunakea in Hawai‘i. NGC 772’s peculiar appearance has earned it a place as the 78th entry in the Atlas of Peculiar Galaxies — a rogues’ gallery of weird and wonderful galaxy structures.

This impressive image shows the strangely lopsided spiral galaxy NGC 772, which lies over 100 million light-years from Earth in the constellation Aries. Captured by the Gemini North telescope in Hawai‘i, one half of the international Gemini Observatory, a Program of NSF’s NOIRLab, the image shows NGC 772’s overdeveloped spiral arm, which stretches across toward the left-hand edge of the frame. This extra large arm is due to one of NGC 772’s unruly neighbors, the dwarf elliptical galaxy NGC 770. The tidal interactions between NGC 772 and its diminutive companion have distorted and stretched one of the spiral galaxy’s arms, giving it the lopsided appearance seen in this image.

NGC 772 also lacks a bright central bar. Other spiral galaxies such as the Andromeda Galaxy or our own Milky Way exhibit prominent central bars — large, linear structures composed of gas, dust, and countless stars. Without a bar, NGC 772’s spiral arms sweep out directly from the bright center of the galaxy. 

The galaxy’s unusual appearance has earned it the distinction of appearing in the Atlas of Peculiar Galaxies, a careful curation by astronomer Halton Arp of some of the weird and wonderful galaxies populating the Universe. The 338 galaxies in the Atlas are a rogues’ gallery of strange and unusual galaxy shapes chosen to provide astronomers with a catalog of odd galaxy structures. Entries in the Atlas of Peculiar Galaxies include galaxies boasting trailing tidal tailsringsjetsdetached segments, and a host of other structural idiosyncrasies. NGC 772 is included as Arp 78.

While NGC 772’s peculiarities dominate this image, there is also a menagerie of galaxies lurking in the background. The bright smears and smudges littering this image are distant galaxies — some of the closer examples can be resolved into characteristic spiral shapes. Every direction on the sky that astronomers have pointed telescopes toward contains a rich carpet of galaxies, with an estimated 2 trillion galaxies in total in our observable Universe.




Links

Contacts

Amanda Kocz
NSF’s NOIRLab Communications
Tel: +1 520 318 8591
Email:
amanda.kocz@noirlab.edu

Source:  Gemini Observatory


Tuesday, March 22, 2022

A View to a Nebula

NGC 6523/Lagoon Nebula

Image Credit: NASA, ESA, and STScI

This colorful image, taken by the Hubble Space Telescope and published in 2018, celebrated the Earth-orbiting observatory’s 28th anniversary of viewing the heavens, giving us a window seat to the universe’s extraordinary tapestry of stellar birth and destruction.

At the center of the photo, a monster young star 200,000 times brighter than our Sun is blasting powerful ultraviolet radiation and hurricane-like stellar winds, carving out a fantasy landscape of ridges, cavities, and mountains of gas and dust.

This mayhem is all happening at the heart of the Lagoon Nebula, a vast stellar nursery located 4,000 light-years away and visible in binoculars simply as a smudge of light with a bright core.

The giant star, called Herschel 36, is bursting out of its natal cocoon of material, unleashing blistering radiation and torrential stellar winds (streams of subatomic particles) that push dust away in curtain-like sheets. This action resembles the Sun bursting through the clouds at the end of an afternoon thunderstorm that showers sheets of rainfall.

Editor: Yvette Smith

Source: NASA/Nebulae


Monday, March 21, 2022

Hubble Spies a Stunning Spiral

NGC 4571
Credits: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team

This cosmic portrait — captured with the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3 — shows a stunning view of the spiral galaxy NGC 4571, which lies approximately 60 million light-years from Earth in the constellation Coma Berenices. This constellation — whose name translates as Bernice’s Hair — was named after an Egyptian queen who lived more than 2200 years ago.

As majestic as spiral galaxies like NGC 4571 are, they are far from the largest structures known to astronomers. NGC 4571 is part of the Virgo cluster, which contains more than a thousand galaxies. This cluster is in turn part of the larger Virgo supercluster, which also encompasses the Local Group which contains our own galaxy, the Milky Way. Even larger than superclusters are galaxy filaments  — the largest known structures in the Universe.

This image comes from a large programme of observations designed to produce a treasure trove of combined observations from two great observatories: Hubble and ALMA. ALMA, The Atacama Large Millimeter/submillimeter Array, is a vast telescope consisting of 66 high-precision antennas high in the Chilean Andes, which together observe at wavelengths between infrared and radio waves. This allows ALMA to detect the clouds of cool interstellar dust which give rise to new stars. Hubble’s razor-sharp observations at ultraviolet wavelengths, meanwhile, allows astronomers to pinpoint the location of hot, luminous, newly formed stars. Together, the ALMA and Hubble observations provide a vital repository of data to astronomers studying star formation, as well as laying the groundwork for future science with the NASA/ESA/CSA James Webb Space Telescope.

Friday, March 18, 2022

NASA Spots Giant Debris Cloud Created by Clashing Celestial Bodies

Planetesimal Collision Around Star HD 166191 (Illustration)
This illustration depicts the result of a collision between two large asteroid-sized bodies. NASA's Spitzer saw a debris cloud block the star HD 166191, giving scientists details about the smashup that occurred. Credit: NASA/JPL-Caltech

Major smashups between rocky bodies shaped our solar system. Observations of a similar crash give clues about how frequent these events are around other stars.

Most of the rocky planets and satellites in our solar system, including Earth and the Moon, were formed or shaped by massive collisions early in the solar system’s history. By smashing together, rocky bodies can accumulate more material, increasing in size, or they can break apart into multiple smaller bodies.

Astronomers using NASA’s now-retired Spitzer Space Telescope have in the past found evidence of these types of collisions around young stars where rocky planets are forming. But those observations didn’t provide many details about the smashups, such as the size of the objects involved.

In a new study in the Astrophysical Journal, a group of astronomers led by Kate Su of the University of Arizona report the first observations of a debris cloud from one of these collisions as it passed in front of its star and briefly blocked the light. Astronomers call this a transit. Coupled with knowledge about the star’s size and brightness, the observations enabled the researchers to directly determine the size of the cloud shortly after impact, estimate the size of the objects that collided, and watch the speed with which the cloud dispersed.

“There is no substitute for being an eyewitness to an event,” said George Rieke, also at the University of Arizona and a coauthor of the new study. “All the cases reported previously from Spitzer have been unresolved, with only theoretical hypotheses about what the actual event and debris cloud might have looked like.”

Beginning in 2015, a team led by Su started making routine observations of a 10 million-year-old star called HD 166191. Around this early time in a star’s life, dust left over from its formation has clumped together to form rocky bodies called planetesimals – seeds of future planets. Once the gas that previously filled the space between those objects has dispersed, catastrophic collisions between them become common.

Anticipating they might see evidence of one of these collisions around HD 166191, the team used Spitzer to conduct more than 100 observations of the system between 2015 and 2019. While the planetesimals are too small and distant to resolve by telescope, their smashups produce large amounts of dust. Spitzer detected infrared light – or wavelengths slightly longer than what human eyes can see. Infrared is ideal for detecting dust, including the debris created by protoplanet collisions.

In mid-2018, the space telescope saw the HD 166191 system become significantly brighter, suggesting an increase in debris production. During that time, Spitzer also detected a debris cloud blocking the star. Combining Spitzer’s observation of the transit with observations by telescopes on the ground, the team could deduce the size and shape of the debris cloud.

Their work suggests the cloud was highly elongated, with a minimum estimated area three times that of the star. However, the amount of infrared brightening Spitzer saw suggests only a small portion of the cloud passed in front of the star and that the debris from this event covered an area hundreds of times larger than that of the star.

To produce a cloud that big, the objects in the main collision must have been the size of dwarf planets, like Vesta in our solar system – an object 330 miles (530 kilometers) wide located in the main asteroid belt between Mars and Jupiter. The initial clash generated enough energy and heat to vaporize some of the material. It also set off a chain reaction of impacts between fragments from the first collision and other small bodies in the system, which likely created a significant amount of the dust Spitzer saw.

Over the next few months, the large dust cloud grew in size and became more translucent, indicating that the dust and other debris were quickly dispersing throughout the young star system. By 2019, the cloud that passed in front of the star was no longer visible, but the system contained twice as much dust as it had before Spitzer spotted the cloud. This information, according to the paper’s authors, can help scientists test theories about how terrestrial planets form and grow.

“By looking at dusty debris disks around young stars, we can essentially look back in time and see the processes that may have shaped our own solar system,” said Su. “Learning about the outcome of collisions in these systems, we may also get a better idea of how frequently rocky planets form around other stars.”

More About Spitzer

The entire body of scientific data collected by Spitzer during its lifetime is available to the public via the Spitzer data archive, housed at the Infrared Science Archive at IPAC at Caltech in Pasadena, California. JPL, a division of Caltech, managed Spitzer mission operations for NASA’s Science Mission Directorate in Washington. Science operations were conducted at the Spitzer Science Center at IPAC at Caltech. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado.

For more information about NASA’s Spitzer mission, go to: https://www.jpl.nasa.gov/missions/spitzer-space-telescope and https://www.ipac.caltech.edu/project/spitzer

News Media Contact

Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469

calla.e.cofield@jpl.nasa.gov

Source:  Spitzer Space Telescope/News


Thursday, March 17, 2022

Hubble Views an Infant Star’s Outburst

HH34
Text credit: European Space Agency
Image credit: ESA/Hubble & NASA, B. Nisini

An energetic outburst from an infant star streaks across this image from the NASA/ESA Hubble Space Telescope. This stellar tantrum – produced by an extremely young star in the earliest phase of formation – consists of an incandescent jet of gas travelling at supersonic speeds. As the jet collides with material surrounding the still-forming star, the shock heats this material and causes it to glow. The result is the colorfully wispy structures, which astronomers refer to as Herbig–Haro objects, billowing across the lower right of this image.

Herbig–Haro objects are seen to evolve and change significantly over just a few years. This particular object, called HH34, was previously captured by Hubble between 1994 and 2007, and again in glorious detail in 2015. HH34 resides approximately 1,250 light-years from Earth in the Orion Nebula, a large region of star formation visible to the unaided eye. The Orion Nebula is one of the closest sites of widespread star formation to Earth, and as such has been pored over by astronomers in search of insights into how stars and planetary systems are born. 

The data in this image are from a set of Hubble observations of four nearby bright jets with the Wide Field Camera 3 taken to help pave the way for future science with the NASA/ESA/CSA James Webb Space Telescope. Webb – which will observe at predominantly infrared wavelengths – will be able to peer into the dusty envelopes surrounding still-forming protostars, revolutionizing the study of jets from these young stars. Hubble’s high-resolution images of HH34 and other jets will help astronomers interpret future observations with Webb.

Media Contact:

Claire Andreoli
NASA's Goddard Space Flight Center
301-286-1940

Editor: Andrea Gianopoulos

Source: NASA/ Hubble



Wednesday, March 16, 2022

NASA’s Webb Reaches Alignment Milestone, Optics Working Successfully


While the purpose of this image was to focus on the bright star at the center for alignment evaluation, Webb's optics and NIRCam are so sensitive that the galaxies and stars seen in the background show up. At this stage of Webb’s mirror alignment, known as “fine phasing,” each of the primary mirror segments have been adjusted to produce one unified image of the same star using only the NIRCam instrument. This image of the star, which is called 2MASS J17554042+6551277, uses a red filter to optimize visual contrast. Credits: NASA/STScI


This new “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of the sky. This configuration is not used during scientific operations and is used strictly for engineering and alignment purposes. In this image, all of Webb’s 18 primary mirror segments are shown collecting light from the same star in unison. Credits: NASA/STScI

Following the completion of critical mirror alignment steps, NASA’s James Webb Space Telescope team expects that Webb’s optical performance will be able to meet or exceed the science goals the observatory was built to achieve.

On March 11, the Webb team completed the stage of alignment known as “fine phasing.” At this key stage in the commissioning of Webb’s Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations. The team also found no critical issues and no measurable contamination or blockages to Webb’s optical path. The observatory is able to successfully gather light from distant objects and deliver it to its instruments without issue.

Although there are months to go before Webb ultimately delivers its new view of the cosmos, achieving this milestone means the team is confident that Webb’s first-of-its-kind optical system is working as well as possible.

“More than 20 years ago, the Webb team set out to build the most powerful telescope that anyone has ever put in space and came up with an audacious optical design to meet demanding science goals,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington. “Today we can say that design is going to deliver.”

While some of the largest ground-based telescopes on Earth use segmented primary mirrors, Webb is the first telescope in space to use such a design. The 21-foot, 4-inch (6.5-meter) primary mirror – much too big to fit inside a rocket fairing – is made up of 18 hexagonal, beryllium mirror segments. It had to be folded up for launch and then unfolded in space before each mirror was adjusted – to within nanometers – to form a single mirror surface.

“In addition to enabling the incredible science that Webb will achieve, the teams that designed, built, tested, launched, and now operate this observatory have pioneered a new way to build space telescopes,” said Lee Feinberg, Webb optical telescope element manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

With the fine phasing stage of the telescope’s alignment complete, the team has now fully aligned Webb’s primary imager, the Near-Infrared Camera, to the observatory’s mirrors.

“We have fully aligned and focused the telescope on a star, and the performance is beating specifications. We are excited about what this means for science,” said Ritva Keski-Kuha, deputy optical telescope element manager for Webb at NASA Goddard. “We now know we have built the right telescope.”

Over the next six weeks, the team will proceed through the remaining alignment steps before final science instrument preparations. The team will further align the telescope to include the Near-Infrared Spectrograph, Mid-Infrared Instrument, and Near InfraRed Imager and Slitless Spectrograph. In this phase of the process, an algorithm will evaluate the performance of each instrument and then calculate the final corrections needed to achieve a well-aligned telescope across all science instruments. Following this, Webb’s final alignment step will begin, and the team will adjust any small, residual positioning errors in the mirror segments.

The team is on track to conclude all aspects of Optical Telescope Element alignment by early May, if not sooner, before moving on to approximately two months of science instrument preparations. Webb’s first full-resolution imagery and science data will be released in the summer.

Webb is the world's premier space science observatory and once fully operational, will help 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 at ESA (European Space Agency) and the Canadian Space Agency.


Credits: NASA's Goddard Space Flight Center

For more information about the Webb mission, visit: https://www.nasa.gov/webb

Contacts:

Natasha Pinol / Alise Fisher
Headquarters, Washington
202-358-0930 / 202-617-4977

Natasha.r.pinol@nasa.gov / alise.m.fisher@nasa.gov

Laura Betz
Goddard Space Flight Center, Greenbelt, Md.
240-357-6833

Laura.e.betz@nasa.gov

Editor: Sean Potter
 



Tuesday, March 15, 2022

A hypnotic golden spiral

NGC 4254
Credits: ESO/PHANGS

This image features the spectacular galaxy NGC 4254, also known as Messier 99. It’s an example of a grand design spiral galaxy, featuring strong, prominent, well-defined arms that wrap clearly around the galaxy’s centre.

Messier 99 is located 49 million light-years from Earth in the constellation of Coma Berenices. Here it was imaged in exquisite detail by the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT). It is a combination of observations conducted in different colours, or wavelengths, of light, showing clouds of gas ionised by newly born stars. Hydrogen, oxygen and sulphur gas are shown in red, blue and orange respectively.

The image was taken as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project, which is making high-resolution observations of nearby galaxies across all wavelengths of the electromagnetic spectrum to understand the life-cycle of star formation in galaxies.

Source: ESO/powt



Monday, March 14, 2022

PSR J2030+4415: Tiny Star Unleashes Gargantuan Beam of Matter and Antimatter Quick Look: Pulsar J2030


PSR J2030+4415
Credit: X-ray: NASA/CXC/Stanford Univ./M. de Vries; Optical: NSF/AURA/Gemini Consortium)

JPEG (320.2 kb) - Large JPEG (7.1 MB) - Tiff (27.4 MB) - More Images

 A Tour of J2030 -  More Animations



This image from NASA's Chandra X-ray Observatory and ground-based optical telescopes shows an extremely long beam, or filament, of matter and antimatter extending from a relatively tiny pulsar, as reported in our latest press release. With its tremendous scale, this beam may help explain the surprisingly large numbers of positrons, the antimatter counterparts to electrons, scientists have detected throughout the Milky Way galaxy.

The panel on the left displays about one third the length of the beam from the pulsar known as PSR J2030+4415 (J2030 for short), which is located about 1,600 light years from Earth. J2030 is a dense, city-sized object that formed from the collapse of a massive star and currently spins about three times per second. X-rays from Chandra (blue) show where particles flowing from the pulsar along magnetic field lines are moving at about a third the speed of light. A close-up view of the pulsar in the right panel shows the X-rays created by particles flying around the pulsar itself. As the pulsar moves through space at about a million miles an hour, some of these particles escape and create the long filament. In both panels, optical light data from the Gemini telescope on Mauna Kea in Hawaii have been used and appear red, brown, and black. The full length of the filament is shown in a separate image.

PSR J2030+4415 (Labeled) - X-Ray
Credit: X-ray: NASA/CXC/Stanford Univ./M. de Vries; Optical: NSF/AURA/Gemini Consortium)

The vast majority of the Universe consists of ordinary matter rather than antimatter. Scientists, however, continue to find evidence for relatively large numbers of positrons in detectors on Earth, which leads to the question: what are possible sources of this antimatter? The researchers in the new Chandra study of J2030 think that pulsars like it may be one answer. The combination of two extremes — fast rotation and high magnetic fields of pulsars — lead to particle acceleration and high energy radiation that creates electron and positron pairs. (The usual process of converting mass into energy famously determined by Einstein's E = mc2 equation is reversed, and energy is converted into mass.)

Pulsars generate winds of charged particles that are usually confined within their powerful magnetic fields. The pulsar is traveling through interstellar space at about half a million miles per hour, with the wind trailing behind it. A bow shock of gas moves along in front of the pulsar, similar to the pile-up of water in front of a moving boat. However, about 20 to 30 years ago the bow shock's motion appears to have stalled and the pulsar caught up to it.

The ensuing collision likely triggered a particle leak, where the pulsar wind's magnetic field linked up with the interstellar magnetic field. As a result, the high-energy electrons and positrons could have squirted out through a "nozzle" formed by connection into the Galaxy.

Previously, astronomers have observed large halos around nearby pulsars in gamma-ray light that imply energetic positrons generally have difficulty leaking out into the Galaxy. This undercut the idea that pulsars explain the positron excess that scientists detect. However, pulsar filaments that have recently been discovered, like J2030, show that particles actually can escape into interstellar space, and eventually could reach Earth.

A paper describing these results, authored by Martjin de Vries and Roger Romani of Stanford University, will appear in The Astrophysical Journal and is available online. NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Quick Look: Pulsar J2030

Source: NASA's Chandra X-Ray Observatory



Fast Facts for PSR J2030+4415:

Scale: Main image is about 5.8 arcmin (2.7 light years) across; Inset image is about 42.5 arcsec (0.33 light years) across.
Category: Neutron Stars/X-ray Binaries
Coordinates (J2000): RA 20h 30m 51.40s | Dec +44° 15´ 38.7"
Constellation:
Cygnus
Observation Date: 8 observations from Apr 15, 2014, Apr 10-15, 2019, Feb 13 and Nov 8, 2021
Observation Time: 69 hours
Obs. ID: 14827, 20298, 22171-22173, 23536, 24954, 24236
Instrument:
ACIS
References: de Vries, M. and Romani, R., 2022, ApJ, Accepted; arXiv:2202.03506
Color Code: X-ray: blue; Optical: red
Distance Estimate: About 1,600 light years


Tuesday, March 08, 2022

Astronomers discover largest molecule yet in a planet-forming disc

Dimethyl ether spotted in disc around IRS 48 star
 
Molecules in the disc around the star IRS 48 
 
Molecules in the disc around the star IRS 48 (composite)
 
ALMA image of comet factory around Oph-IRS 48 
 
ALMA and VLT image of comet factory around Oph-IRS 48 
 
ALMA image of dust trap/comet factory around Oph-IRS 48 (annotated) 
 
The location of the system Oph-IRS 48 in the constellation of Ophiuchus



Videos
 
Largest Molecule yet Spotted in a Planet-forming Disc (ESOcast 253 Light)
Largest Molecule yet Spotted in a Planet-forming Disc (ESOcast 253 Light) 
 
Artist’s animation of the dust trap in IRS 48
Artist’s animation of the dust trap in IRS 48 
 
Zooming in on the Oph-IRS 48 system
Zooming in on the Oph-IRS 48 system



Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers at Leiden Observatory in the Netherlands have for the first time detected dimethyl ether in a planet-forming disc. With nine atoms, this is the largest molecule identified in such a disc to date. It is also a precursor of larger organic molecules that can lead to the emergence of life.

"From these results, we can learn more about the origin of life on our planet and therefore get a better idea of the potential for life in other planetary systems. It is very exciting to see how these findings fit into the bigger picture," says Nashanty Brunken, a Master's student at Leiden Observatory, part of Leiden University, and lead author of the study published today in Astronomy & Astrophysics.

Dimethyl ether is an organic molecule commonly seen in star-forming clouds, but had never before been found in a planet-forming disc. The researchers also made a tentative detection of methyl formate, a complex molecule similar to dimethyl ether that is also a building block for even larger organic molecules.

"It is really exciting to finally detect these larger molecules in discs. For a while we thought it might not be possible to observe them,” says co-author Alice Booth, also a researcher at Leiden Observatory.

The molecules were found in the planet-forming disc around the young star IRS 48 (also known as Oph-IRS 48) with the help of ALMA, an observatory co-owned by the European Southern Observatory (ESO). IRS 48, located 444 light-years away in the constellation Ophiuchus, has been the subject of numerous studies because its disc contains an asymmetric, cashew-nut-shaped “dust trap”. This region, which likely formed as a result of a newly born planet or small companion star located between the star and the dust trap, retains large numbers of millimetre-sized dust grains that can come together and grow into kilometre-sized objects like comets, asteroids and potentially even planets.

Many complex organic molecules, such as dimethyl ether, are thought to arise in star-forming clouds, even before the stars themselves are born. In these cold environments, atoms and simple molecules like carbon monoxide stick to dust grains, forming an ice layer and undergoing chemical reactions, which result in more complex molecules. Researchers recently discovered that the dust trap in the IRS 48 disc is also an ice reservoir, harbouring dust grains covered with this ice rich in complex molecules. It was in this region of the disc that ALMA has now spotted signs of the dimethyl ether molecule: as heating from IRS 48 sublimates the ice into gas, the trapped molecules inherited from the cold clouds are freed and become detectable.

What makes this even more exciting is that we now know these larger complex molecules are available to feed forming planets in the disc,” explains Booth. “This was not known before as in most systems these molecules are hidden in the ice.

The discovery of dimethyl ether suggests that many other complex molecules that are commonly detected in star-forming regions may also be lurking on icy structures in planet-forming discs. These molecules are the precursors of prebiotic molecules such as amino acids and sugars, which are some of the basic building blocks of life.

By studying their formation and evolution, researchers can therefore gain a better understanding of how prebiotic molecules end up on planets, including our own. “We are incredibly pleased that we can now start to follow the entire journey of these complex molecules from the clouds that form stars, to planet-forming discs, and to comets. Hopefully with more observations we can get a step closer to understanding the origin of prebiotic molecules in our own Solar System,” says Nienke van der Marel, a Leiden Observatory researcher who also participated in the study.

Future studies of IRS 48 with ESO’s Extremely Large Telescope (ELT), currently under construction in Chile and set to start operations later this decade, will allow the team to study the chemistry of the very inner regions of the disc, where planets like Earth may be forming.



More Information

This research was presented in the paper "A major asymmetric ice trap in a planet-forming disk: III. First detection of dimethyl ether" (doi: 10.1051/0004-6361/202142981) to appear in Astronomy and Astrophysics.

This publication was released on International Women’s Day 2022 and features research undertaken by six researchers who identify as women.

The team is composed of Nashanty G. C. Brunken (Leiden Observatory, Leiden University,  Netherlands [Leiden]), Alice S. Booth (Leiden), Margot Leemker (Leiden), Pooneh Nazari (Leiden),  Nienke van der Marel (Leiden),  Ewine F. van Dishoeck (Leiden Observatory, Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany)

The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration in astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 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 as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its 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. Together with international partners, ESO operates APEX and ALMA on Chajnantor, two facilities that observe the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.



Links



Contacts:

Nashanty Brunken
Leiden Observatory, Leiden University
Leiden, The Netherlands
Email: brunken@strw.leidenuniv.nl

Alice Booth
Leiden Observatory, Leiden University
Leiden, The Netherlands
Tel: +31 71 527 5737
Email: abooth@strw.leidenuniv.nl

Nienke van der Marel
Leiden Observatory, Leiden University
Leiden, The Netherlands
Tel: +31 71 527 5872
Email: nmarel@strw.leidenuniv.nl

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: press@eso.org

Source: ESO/News