An Accidental Discovery Hints at a Hidden Population of Cosmic Objects

This mosaic shows the entire sky imaged by the Wide-field Infrared Survey Explorer (WISE). Infrared light refers to wavelengths that are longer than those visible to the human eye. Many cosmic objects radiate infrared, including gas and dust clouds where stars form, and brown dwarfs. Credit: NASA/JPL-Caltech/UCLA 

A new studyoffers a tantalizing explanation for how a peculiar cosmic object called WISEA J153429.75-104303.3 – nicknamed “The Accident” – came to be. The Accident is a brown dwarf. Though they form like stars, these objects don’t have enough mass to kickstart nuclear fusion, the process that causes stars to shine. And while brown dwarfs sometimes defy characterization, astronomers have a good grasp on their general characteristics.

Or they did, until they found this one.

The Accident got its name after being discovered by sheer luck. It slipped past normal searches because it doesn’t resemble any of the just over 2,000 brown dwarfs that have been found in our galaxy so far.

Can you see the dark spot moving in the bottom left corner of the screen? It’s a brown dwarf nicknamed “The Accident,” which was discovered by citizen scientist Dan Caselden. It had slipped past typical searches because it doesn’t look like any other known brown dwarfs. Credit: NASA/JPL-Caltech/Dan Caselden. Images

As brown dwarfs age, they cool off, and their brightness in different wavelengths of light changes. It’s not unlike how some metals, when heated, go from bright white to deep red as they cool. The Accident confused scientists because it was faint in some key wavelengths, suggesting it was very cold (and old), but bright in others, indicating a higher temperature.

“This object defied all our expectations,” said Davy Kirkpatrick, an astrophysicist at IPAC at Caltech in Pasadena, California. He and his co-authors posit in their new study, appearing in the Astrophysical Journal Letters, that The Accident might be 10 billion to 13 billion years old – at least double the median age of other known brown dwarfs. That means it would have formed when our galaxy was much younger and had a different chemical makeup. If that’s the case, there are likely many more of these ancient brown dwarfs lurking in our galactic neighborhood.

A Peculiar Profile

The Accident was first spotted by NASA’s Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE), launched in 2009 under the moniker WISE and managed by NASA’s Jet Propulsion Laboratory in Southern California. Because brown dwarfs are relatively cool objects, they radiate mostly infrared light, or wavelengths longer than what the human eye can see.

Brown dwarfs share certain characteristics with both stars and planets. Generally, they are less massive than stars and more massive than planets. A brown dwarf becomes a star if its core pressure gets high enough to start nuclear fusion, the process that causes stars to shine. Credit: NASA/JPL-Caltech

To figure out how The Accident could have such seemingly contradictory properties – some suggesting it is very cold, others indicating it is much warmer – the scientists needed more information. So they observed it in additional infrared wavelengths with a ground-based telescope at the W. M. Keck Observatory in Hawaii. But the brown dwarf appeared so faint in those wavelengths, they couldn’t detect it at all, apparently confirming their suggestion that it was very cold.

They next set out to determine if the dimness resulted from The Accident being farther than expected from Earth. But that wasn’t the case, according to precise distance measurements by NASA’s Hubble and Spitzer Space Telescopes. Having determined the object’s distance – about 50 light-years from Earth – the team realized that it is moving fast – about half a million miles per hour (800,000 kph). That’s much faster than all other brown dwarfs known to be at this distance from Earth, which means it has probably been careening around the galaxy for a long time, encountering massive objects that accelerate it with their gravity.

With a mound of evidence suggesting The Accident is extremely old, the researchers propose that its strange properties aren’t strange at all and that they may be a clue to its age.

When the Milky Way formed about 13.6 billion years ago, it was composed almost entirely of hydrogen and helium. Other elements, like carbon, formed inside stars; when the most massive stars exploded as supernovae, they scattered the elements throughout the galaxy.

Methane, composed of hydrogen and carbon, is common in most brown dwarfs that have a temperature similar to The Accident. But The Accident’s light profile suggests it contains very little methane. Like all molecules, methane absorbs specific wavelengths of light, so a methane-rich brown dwarf would be dim in those wavelengths. The Accident, by contrast, is bright in those wavelengths, which could indicate low levels of methane.

Thus, the light profile of The Accident could match that of a very old brown dwarf that formed when the galaxy was still carbon poor; very little carbon at formation means very little methane in its atmosphere today.

“It’s not a surprise to find a brown dwarf this old, but it is a surprise to find one in our backyard,” said Federico Marocco, an astrophysicist at IPAC at Caltech who led the new observations using the Keck and Hubble telescopes. “We expected that brown dwarfs this old exist, but we also expected them to be incredibly rare. The chance of finding one so close to the solar system could be a lucky coincidence, or it tells us that they’re more common than we thought.”

This artist’s illustration shows a dim, cold brown dwarf in space. Brown dwarfs form like stars, but do not have enough mass to ignite nuclear fusion in their cores – the process that causes stars to burn. As a result they share some physical characteristics with massive planets, like Jupiter. Credit: IPAC/Caltech

A Lucky Accident

To find more ancient brown dwarfs like The Accident – if they’re out there – researchers might have to change how they search for these objects.

The Accident was discovered by citizen scientist Dan Caselden, who was using an online program he built to find brown dwarfs in NEOWISE data. The sky is full of objects that radiate infrared light; by and large, these objects appear to remain fixed in the sky, due to their great distance from Earth. But because brown dwarfs are so faint, they are visible only when they’re relatively close to Earth, and that means scientists can observe them moving across the sky over months or years. (NEOWISE maps the entire sky about once every six months.)

Caselden’s program attempted to remove the stationary infrared objects (like distant stars) from the NEOWISE maps and highlight moving objects that had similar characteristics to known brown dwarfs. He was looking at one such brown dwarf candidate when he spotted another, much fainter object moving quickly across the screen. This would turn out to be WISEA J153429.75-104303.3, which hadn’t been highlighted because it did not match the program’s profile of a brown dwarf. Caselden caught it by accident.

“This discovery is telling us that there’s more variety in brown dwarf compositions than we’ve seen so far,” said Kirkpatrick. “There are likely more weird ones out there, and we need to think about how to look for them.”

Source:  Spitzer Space Telescope/News

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More About the Missions

Launched in 2009, the WISE spacecraft was placed into hibernation in 2011 after completing its primary mission. In September 2013, NASA reactivated the spacecraft with the primary goal of scanning for near-Earth objects, or NEOs, and the mission and spacecraft were renamed NEOWISE. JPL, a division of Caltech, managed and operated WISE for NASA’s Science Mission Directorate (SMD). The mission was selected competitively under NASA’s Explorers Program managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland. NEOWISE is a project of JPL, a division of Caltech, and the University of Arizona, supported by NASA’s Planetary Defense Coordination Office.

For more information about WISE, go to: https://www.nasa.gov/mission_pages/WISE/main/index.html

JPL managed Spitzer mission operations for NASA’s SMD until the spacecraft was retired in 2020. Science operations were conducted at the Spitzer Science Center at IPAC at Caltech. Spacecraft operations were based at Lockheed Martin Space in Littleton, Colorado. The Spitzer data archive is housed at the Infrared Science Archive at IPAC at Caltech.

For more information about NASA’s Spitzer mission, go to:

https://www.nasa.gov/mission_pages/spitzer/main/index.html  /  https://www.ipac.caltech.edu/project/spitzer

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.

For more information about NASA’s Hubble, go to:https://www.nasa.gov/mission_pages/hubble/main/index.html

For more opportunities to participate in NASA Citizen Science Projects, go to: https://science.nasa.gov/citizenscience

 

News Media Contact

Calla Cofield

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calla.e.cofield@jpl.nasa.gov

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Pre-Supernova Burps and Red Supergiant Reflux

SN 1987A is an example of a supernova that collided with circumstellar material as it expanded.
Credit: ESA/Hubble, NASA

Title: 3D Hydrodynamics of Pre-supernova Outbursts in Convective Red Supergiant Envelopes
Authors: Benny T.-H. Tsang, Daniel Kasen, and Lars Bildsten
First Author’s Institution: University of California, Berkeley
Status: Published in ApJ

All right, I know what you’re thinking: “What do my digestive problems (for the hopefully very few of you) have to do with a star’s last, quite spectacular, goodbye?” Unlike most humans, stars don’t possess working intestines, and their outbursts — supernovae — are far more impressive than anything we can manage. There are many different kinds of supernovae, but they are broadly split into two categories: Type I and Type II. We typically see no emission lines of hydrogen in the spectra of Type I supernovae (here’s an example of why), while the spectra of Type II supernovae do contain hydrogen lines. We will talk about this latter type in today’s bite.

Red Supergiant Burps and Interacting Supernovae

Before red supergiants go supernova, they are prone to breathtaking belches called pre-supernova outbursts. These outbursts push huge amounts of gas from the star out into the so-called circumstellar medium — the material in the star’s direct neighborhood. If this neighborhood is filled with enough gas when a star dies, the expanding supernova will push against and interact with this material. This interplay between the material around the star and the supernova can actually be observed from Earth, giving rise to what is known as a Type IIn or interacting supernova.

How visible this interaction is depends mostly on how much material is in the stellar neighborhood. This depends again on how much gas the star decides to throw out, and also on how these pre-supernova outbursts (or burps) are actually formed. The authors of today’s article show that this has a lot to do with convection in the red supergiant.

Red Supergiant Boiling Pot

Simulating these red supergiant outbursts shortly before they go supernova is not new, so we already know the causes of these pre-supernova outbursts:

• Increasingly unstable nuclear fusion in the core of the star causes powerful gravity waves (not to be confused with gravitational waves)
• Large-scale convection in the red supergiant carries around material in the star, which can destabilize the nuclear fusion in the core, giving a very variable energy output
• Pair instability can cause the core’s energy output to go through cycles of drops and spikes
• A binary companion star can disturb the red supergiant enough to cause the star to temporarily become unstable

The bottom line is that some process releases a large amount of extra energy inside the star, which, depending on how the star reacts to this energy release, can lead to different outbursts of gas. Until now, the simulations of these outbursts have usually been spherically symmetric, meaning that the simulation of the outburst looks exactly the same from any direction. You can also see this as a simulation along a single line of sight from the outside of the star inwards (i.e., one-dimensional).

The problem with this approach is that you cannot simulate convection this way. To deal with convection, the authors of today’s article took the brute-force approach and did a fully 3D simulation. They simulated the region of the star outside the nuclear core (called the envelope) and started with a large energy release at the innermost part of their simulation. The authors considered different styles of energy release in the envelope. These included:

• A large, sudden energy release, comparable to the energy needed to keep the star together by gravity. This can cause a mass ejection, quite like the Sun but on much larger scales.
• A slow release of energy, which causes a much steadier stream of mass flowing away from the star instead of an explosive loss of mass.
• Varying direction of energy release, which influences how (and where to) the pre-supernova outburst will occur.

A snapshot of the authors’ simulation is shown in Figure 1. Here, we see both the envelope density on the left and the velocity of the envelope gas in the radial direction on the right. In the velocity graph, we can see zones both moving away from the star and falling back towards the core. These are the same as convection cells we can find in daily life — like in a pot of boiling water.

Figure 1: Left: Density slice of the star’s outer layers, with radius (R) vs. the distance from the core to the pole (z). Right: Velocity in the radial direction (away from the core) slice with the same axes as on the left. Credit: Tsang et al. 2022

The convection cells leave “holes” or channels of lower density in the envelope from the outside to inner parts of the star. Through these channels, much more gas can escape than would be possible without convection.

We can also see this in Figure 2: the simulation in the left panel, which included the convection, resulted in much more mass loss than the simulation in the right panel, which did not. These channels of low density appear where most of the mass escapes in the convection simulation.

Figure 2: Two images of the star’s surface in Mollweide projection, showing how much mass has escaped. On the left is a model with convection, where the colors indicate the amount of mass lost per direction (or, specifically, solid angle). On the right is a simulation without convection. Credit: Tsang et al. 2022

This article shows the necessity of taking convection in 3D into account, where the loss of mass from the pre-supernova outbursts has mostly been underestimated. This increases the amount of gas in the neighborhood of the red supergiant, ultimately affecting how the interacting supernova will look to us on Earth.

Source: American Astronomical Society - AAS Nova 

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By Astrobites

Editor’s Note: Astrobites is a graduate-student-run organization that digests astrophysical literature for undergraduate students. As part of the partnership between the AAS and astrobites, we occasionally repost astrobites content here at AAS Nova. We hope you enjoy this post from astrobites; the original can be viewed at astrobites.org.

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About the author, Roel Lefever:

Roel is a first-year PhD student at Heidelberg University, studying astrophysics. He works on massive stars and simulates their atmospheres/outflows. In his spare time, he likes to hike/bike in nature, play (a whole lot of) video games, play/listen to music (movie soundtracks!), and to read (currently The Wheel of Time, but any fantasy really).

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Featured Image: First Images of a Substellar Companion in the Hyades

Images of the companion object (circled) taken over the course of a year. The companion object is detected with a signal-to-noise ratio ranging from 10 to 19. Credit: Kuzuhara et al. 2022

Astronomers have photographed a substellar object in orbit around a star in the Hyades, the nearest star cluster to Earth, for the first time. Previous data from the Gaia and Hipparcos satellites showed the Sun-like star HIP 21152 accelerating under the influence of an unseen companion. Now, a team led by Masayuki Kuzuhara (Astrobiology Center of the National Institutes of Natural Sciences and the National Astronomical Observatory of Japan) has obtained new Subaru and Keck telescope images, shown above and to the right, of HIP 21152 and its surroundings. These images reveal HIP 21152’s companion, which Kuzuhara and collaborators determined to be a 27.8-Jupiter-mass object orbiting the star at a distance of 17.5 au. Spectra of the object suggest that it is a T dwarf with a temperature between 1200K and 1300K. This discovery is exciting for a number of reasons, chief among them the object’s membership in the Hyades cluster; because the age of the cluster is well known, the newly discovered object will provide a useful reference point for studies of how substellar objects evolve over time.

Citation

“Direct-imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS,” Masayuki Kuzuhara et al 2022 ApJL 934 L18. doi:10.3847/2041-8213/ac772f

Source:  American Astronomical Society - AAS Nova

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NASA’s Webb Detects Carbon Dioxide in Exoplanet Atmosphere

Exoplanet WASP-39 b and Its Star (Illustration)
Credits: Artwork: NASA, ESA, CSA, Joseph Olmsted (STScI)

Exoplanet WASP-39 b (NIRSpec Transmission Spectrum)
Credits: Illustration: NASA, ESA, CSA, Leah Hustak (STScI), Joseph Olmsted (STScI)

Exoplanet WASP-39 b (NIRSpec Transit Light Curves)
Credits: Illustration: NASA, ESA, CSA, Leah Hustak (STScI), Joseph Olmsted (STScI)

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NASA’s James Webb Space Telescope has captured the first clear evidence for carbon dioxide in the atmosphere of a planet outside the solar system. This observation of a gas giant planet orbiting a Sun-like star 700 light-years away provides important insights into the composition and formation of the planet. The finding , which is accepted for publication in Nature, offers evidence that in the future Webb may be able to detect and measure carbon dioxide in the thinner atmospheres of smaller, rocky planets.

WASP-39 b is a hot gas giant with a mass roughly one-quarter that of Jupiter (about the same as Saturn) and a diameter 1.3 times greater than Jupiter. Its extreme puffiness is related in part to its high temperature (about 1,600 degrees Fahrenheit or 900 degrees Celsius). Unlike the cooler, more compact gas giants in our solar system, WASP-39 b orbits very close to its star – only about one-eighth the distance between the Sun and Mercury – completing one circuit in just over four Earth-days. The planet’s discovery, reported in 2011, was made based on ground-based detections of the subtle, periodic dimming of light from its host star as the planet transits , or passes in front of the star.

Previous observations from other telescopes, including NASA’s Hubble and Spitzer space telescopes, revealed the presence of water vapor, sodium, and potassium in the planet’s atmosphere. Webb’s unmatched infrared sensitivity has now confirmed the presence of carbon dioxide on this planet as well.

Filtered Starlight

Transiting planets like WASP-39 b, whose orbits we observe edge-on rather than from above, can provide researchers with ideal opportunities to probe planetary atmospheres. During a transit, some of the starlight is eclipsed by the planet completely (causing the overall dimming) and some is transmitted through the planet’s atmosphere.

Because different gases absorb different combinations of colors, researchers can analyze small differences in brightness of the transmitted light across a spectrum of wavelengths to determine exactly what an atmosphere is made of. With its combination of inflated atmosphere and frequent transits, WASP-39 b is an ideal target for transmission spectroscopy.

First Clear Detection of Carbon Dioxide

The research team used Webb’s Near-Infrared Spectrograph (NIRSpec) for its observations of WASP-39 b. In the resulting spectrum of the exoplanet’s atmosphere, a small hill between 4.1 and 4.6 microns presents the first clear, detailed evidence for carbon dioxide ever detected in a planet outside the solar system.

"As soon as the data appeared on my screen, the whopping carbon dioxide feature grabbed me,” said Zafar Rustamkulov, a graduate student at Johns Hopkins University and member of the JWST Transiting Exoplanet Community Early Release Science team, which undertook this investigation. “It was a special moment, crossing an important threshold in exoplanet sciences.”

No observatory has ever measured such subtle differences in brightness of so many individual colors across the 3 to 5.5-micron range in an exoplanet transmission spectrum before. Access to this part of the spectrum is crucial for measuring abundances of gases like water and methane, as well as carbon dioxide, which are thought to exist in many different types of exoplanets.

“Detecting such a clear signal of carbon dioxide on WASP-39 b bodes well for the detection of atmospheres on smaller, terrestrial-sized planets,” said Natalie Batalha of the University of California at Santa Cruz, who leads the team.

Understanding the composition of a planet’s atmosphere is important because it tells us something about the origin of the planet and how it evolved. “Carbon dioxide molecules are sensitive tracers of the story of planet formation,” said Mike Line of Arizona State University, another member of this research team. “By measuring this carbon dioxide feature, we can determine how much solid versus how much gaseous material was used to form this gas giant planet. In the coming decade, JWST will make this measurement for a variety of planets, providing insight into the details of how planets form and the uniqueness of our own solar system.”  

 

Early Release Science

This NIRSpec prism observation of WASP-39 b is just one part of a larger investigation that includes observations of the planet using multiple Webb instruments, as well as observations of two other transiting planets. The investigation, which is part of the Early Release Science program, was designed to provide the exoplanet research community with robust Webb data as soon as possible.

“The goal is to analyze the Early Release Science observations quickly and develop open-source tools for the science community to use,” explained Vivien Parmentier, a co-investigator from Oxford University. “This enables contributions from all over the world and ensures that the best possible science will come out of the coming decades of observations.”

Natasha Batalha, co-author on the paper from NASA's Ames Research Center, adds that "NASA's open science guiding principles are centered in our Early Release Science work, supporting an inclusive, transparent, and collaborative scientific process."

The James Webb Space Telescope is the world's premier space science observatory. 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.

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Credits:

Release: NASA, ESA, CSA, STScI

Media Contact:

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Space Telescope Science Institute, Baltimore, Maryland

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Science: JWST Transiting Exoplanet Community Early Release Science Team

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Contact Us: Direct inquiries to the News Team.

Related Links and Documents: The science paper by the JWST Transiting Exoplanet Community Early Release Science Team

Source: NASA's James Webb Space Telescope

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Case Solved: Missing Carbon Monoxide was Hiding in the Ice

Credit Required: M.Weiss/Center for Astrophysics | Harvard & Smithsonian

In planetary disks, carbon monoxide is lurking in large chunks of ice, solving the decade-old question, 'Where is the CO?'

Cambridge, MA – Astronomers frequently observe carbon monoxide in planetary nurseries. The compound is ultra-bright and extremely common in protoplanetary disks — regions of dust and gas where planets form around young stars — making it a prime target for scientists.

But for the last decade or so, something hasn't been adding up when it comes to carbon monoxide observations, says Diana Powell, a NASA Hubble Fellow at the Center for Astrophysics | Harvard & Smithsonian.

A huge chunk of carbon monoxide is missing in all observations of disks, if astronomers' current predictions of its abundance are correct.

Now, a new model — validated by observations with ALMA — has solved the mystery: carbon monoxide has been hiding in ice formations within the disks. The findings are described today in the journal Nature Astronomy.

"This may be one of the biggest unsolved problems in planet-forming disks," says Powell, who led the study. "Depending on the system observed, carbon monoxide is three to 100 times less than it should be; it's off by a really huge amount."

And carbon monoxide inaccuracies could have huge implications for the field of astrochemistry.

"Carbon monoxide is essentially used to trace everything we know about disks — like mass, composition and temperature," Powell explains. "This could mean many of our results for disks have been biased and uncertain because we don't understand the compound well enough."

Intrigued by the mystery, Powell put on her detective hat and leaned on her expertise in the physics behind phase changes — when matter morphs from one state to another, like a gas changing into a solid.

On a hunch, Powell made alterations to an astrophysical model that's currently used to study clouds on exoplanets, or planets beyond our solar system.

"What's really special about this model is that it has detailed physics for how ice forms on particles," she explains. "So how ice nucleates onto small particles and then how it condenses. The model carefully tracks where ice is, on what particle it's located on, how big the particles are, how small they are and then how they move around."

Powell applied the adapted model to planetary disks, hoping to generate an in-depth understanding of how carbon monoxide evolves over time in planetary nurseries. To test the model’s validity, Powell then compared its output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya, HD 163296, DM Tau and IM Lup.

The results and models worked really well, Powell says.

The new model lined up with each of the observations, showing that the four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice, which is currently undetectable with a telescope.

Radio observatories like ALMA allow astronomers to view carbon monoxide in space in its gas phase, but ice is much harder to detect with current technology, especially large formations of ice, Powell says.

The model shows that unlike previous thinking, carbon monoxide is forming on large particles of ice — especially after one million years. Prior to a million years, gaseous carbon monoxide is abundant and detectable in disks.

"This changes how we thought ice and gas were distributed in disks," Powell says. "It also shows that detailed modelling like this is important to understand the fundamentals of these environments."

Powell hopes her model can be further validated using observations with NASA’s Webb Telescope — which may be powerful enough to finally detect ice in disks, but that remains to be seen.

Powell, who loves phase changes and the complicated processes behind them, says she is in awe of their influence. "Small-scale ice formation physics influences disk formation and evolution — now that’s really cool."

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Source: Harvard-Smithsonian Center for Astrophysics (CfA)

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Webb’s Jupiter Images Showcase Auroras, Hazes

Webb NIRCam composite image of Jupiter from three filters – F360M (red), F212N (yellow-green), and F150W2 (cyan) – and alignment due to the planet’s rotation. Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Judy Schmidt. Hi-res image

With giant storms, powerful winds, auroras, and extreme temperature and pressure conditions, Jupiter has a lot going on. Now, NASA’s James Webb Space Telescope has captured new images of the planet. Webb’s Jupiter observations will give scientists even more clues to Jupiter’s inner life.

“We hadn’t really expected it to be this good, to be honest,” said planetary astronomer Imke de Pater, professor emerita of the University of California, Berkeley. De Pater led the observations of Jupiter with Thierry Fouchet, a professor at the Paris Observatory, as part of an international collaboration for Webb’s Early Release Science program. Webb itself is an international mission led by NASA with its partners ESA (European Space Agency) and CSA (Canadian Space Agency). “It’s really remarkable that we can see details on Jupiter together with its rings, tiny satellites, and even galaxies in one image,” she said.

The two images come from the observatory’s Near-Infrared Camera (NIRCam), which has three specialized infrared filters that showcase details of the planet. Since infrared light is invisible to the human eye, the light has been mapped onto the visible spectrum. Generally, the longest wavelengths appear redder and the shortest wavelengths are shown as more blue. Scientists collaborated with citizen scientist Judy Schmidt to translate the Webb data into images.

In the standalone view of Jupiter, created from a composite of several images from Webb, auroras extend to high altitudes above both the northern and southern poles of Jupiter. The auroras shine in a filter that is mapped to redder colors, which also highlights light reflected from lower clouds and upper hazes. A different filter, mapped to yellows and greens, shows hazes swirling around the northern and southern poles. A third filter, mapped to blues, showcases light that is reflected from a deeper main cloud.

The Great Red Spot, a famous storm so big it could swallow Earth, appears white in these views, as do other clouds, because they are reflecting a lot of sunlight.

“The brightness here indicates high altitude – so the Great Red Spot has high-altitude hazes, as does the equatorial region,” said Heidi Hammel, Webb interdisciplinary scientist for solar system observations and vice president for science at AURA. “The numerous bright white ‘spots’ and ‘streaks’ are likely very high-altitude cloud tops of condensed convective storms.” By contrast, dark ribbons north of the equatorial region have little cloud cover.

Webb NIRCam composite image from two filters – F212N (orange) and F335M (cyan) – of Jupiter system, unlabeled (top) and labeled (bottom). Credit: NASA, ESA, CSA, Jupiter ERS Team; image processing by Ricardo Hueso (UPV/EHU) and Judy Schmidt. Hi-res image / Hi-res image (labeled)

In a wide-field view, Webb sees Jupiter with its faint rings, which are a million times fainter than the planet, and two tiny moons called Amalthea and Adrastea. The fuzzy spots in the lower background are likely galaxies “photobombing” this Jovian view.

“This one image sums up the science of our Jupiter system program, which studies the dynamics and chemistry of Jupiter itself, its rings, and its satellite system,” Fouchet said. Researchers have already begun analyzing Webb data to get new science results about our solar system’s largest planet.

Data from telescopes like Webb doesn’t arrive on Earth neatly packaged. Instead, it contains information about the brightness of the light on Webb’s detectors. This information arrives at the Space Telescope Science Institute (STScI), Webb’s mission and science operations center, as raw data. STScI processes the data into calibrated files for scientific analysis and delivers it to the Mikulski Archive for Space Telescopes for dissemination. Scientists then translate that information into images like these during the course of their research (here’s a podcast about that). While a team at STScI formally processes Webb images for official release, non-professional astronomers known as citizen scientists often dive into the public data archive to retrieve and process images, too.

Judy Schmidt of Modesto California, a longtime image processor in the citizen science community, processed these new views of Jupiter. For the image that includes the tiny satellites, she collaborated with Ricardo Hueso, a co-investigator on these observations, who studies planetary atmospheres at the University of the Basque Country in Spain.

Citizen scientist Judy Schmidt of Modesto, California, processes astronomical images from NASA spacecraft, such as the Hubble Space Telescope. An example of her work is Minkowski’s Butterfly, right, a planetary nebula in the direction of the constellation Ophiuchus.

Schmidt has no formal educational background in astronomy. But 10 years ago, an ESA contest sparked her insatiable passion for image processing. The “Hubble’s Hidden Treasures” competition invited the public to find new gems in Hubble data. Out of nearly 3,000 submissions, Schmidt took home third place for an image of a newborn star.

Since the ESA contest, she has been working on Hubble and other telescope data as a hobby. “Something about it just stuck with me, and I can’t stop,” she said. “I could spend hours and hours every day.”

Her love of astronomy images led her to process images of nebulae, globular clusters, stellar nurseries, and more spectacular cosmic objects. Her guiding philosophy is: “I try to get it to look natural, even if it’s not anything close to what your eye can see.” These images have caught the attention of professional scientists, including Hammel, who previously collaborated with Schmidt on refining Hubble images of comet Shoemaker-Levy 9’s Jupiter impact.

Jupiter is actually harder to work with than more distant cosmic wonders, Schmidt says, because of how fast it rotates. Combining a stack of images into one view can be challenging when Jupiter’s distinctive features have rotated during the time that the images were taken and are no longer aligned. Sometimes she has to digitally make adjustments to stack the images in a way that makes sense.

Webb will deliver observations about every phase of cosmic history, but if Schmidt had to pick one thing to be excited about, it would be more Webb views of star-forming regions. In particular, she is fascinated by young stars that produce powerful jets in small nebula patches called Herbig–Haro objects. “I’m really looking forward to seeing these weird and wonderful baby stars blowing holes into nebulas,” she said.

– Elizabeth Landau, NASA Headquarters 

Alise Fisher 

Posted on August 22, 2022 

Categories James Webb Space Telescope

Source: Blog/NASA/Webb

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A Marvel of Galactic Morphology

NGC 1156C
Credit:ESA/Hubble & NASA, R. B. Tully, R. Jansen, R. Windhorst

The galaxy featured in this Picture of the Week has a shape unlike many of the galaxies familiar to Hubble. Its thousands of bright stars evoke a spiral galaxy, but it lacks the characteristic ‘winding’ structure. The shining red blossoms stand out as well, twisted by clouds of dust — these are the locations of intense star formation. Yet it also radiates a diffuse glow, much like an elliptical galaxy and its core of older, redder stars. This galactic marvel is known to astronomers as NGC 1156.

NGC 1156 is located around 25 million light-years from Earth, in the constellation Aries. It has a variety of different features that are of interest to astronomers. A dwarf irregular galaxy, it’s also classified as isolated, meaning no other galaxies are nearby enough to influence its odd shape and continuing star formation. The extreme energy of freshly formed young stars gives colour to the galaxy, against the red glow of ionised hydrogen gas, while its centre is densely-packed with older generations of stars.

Hubble has captured NGC 1156 before — this new image features data from a galactic gap-filling programme simply titled “Every Known Nearby Galaxy”. Astronomers noticed that only three quarters of the galaxies within just over 30 million light-years of Earth had been observed by Hubble in sufficient detail to study the makeup of the stars within them. They proposed that in between larger projects, Hubble could take snapshots of the remaining quarter — including NGC 1156. Gap-filling programmes like this one ensure that the best use is made of Hubble’s valuable observing time.

Source:ESA/Hubble/potw

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Sharpest Image Ever of Universe’s Most Massive Known Star

PR Image noirlab2220a

Sharpest Image Ever of R136a1, Largest Known Star

PR Image noirlab2220b

Comparison Observation of R136a1, Zorro and Hubble (Annotated) 

 

Image noirlab2220c

Illustration of Largest Known Star in the Universe

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Groundbreaking observation from Gemini Observatory suggests this and possibly other colossal stars are less massive than previously thought

By harnessing the capabilities of the 8.1-meter Gemini South telescope in Chile, which is part of the International Gemini Observatory operated by NSF’s NOIRLab, astronomers have obtained the sharpest image ever of the star R136a1, the most massive known star in the Universe. Their research, led by NOIRLab astronomer Venu M. Kalari, challenges our understanding of the most massive stars and suggests that they may not be as massive as previously thought.

Astronomers have yet to fully understand how the most massive stars — those more than 100 times the mass of the Sun — are formed. One particularly challenging piece of this puzzle is obtaining observations of these giants, which typically dwell in the densely populated hearts of dust-shrouded star clusters. Giant stars also live fast and die young, burning through their fuel reserves in only a few million years. In comparison, our Sun is less than halfway through its 10 billion year lifespan. The combination of densely packed stars, relatively short lifetimes, and vast astronomical distances makes distinguishing individual massive stars in clusters a daunting technical challenge. 

By pushing the capabilities of the Zorro instrument on the Gemini South telescope of the International Gemini Observatory, operated by NSF’s NOIRLab, astronomers have obtained the sharpest-ever image of R136a1 — the most massive known star. This colossal star is a member of the R136 star cluster, which lies about 160,000 light-years from Earth in the center of the Tarantula Nebula in the Large Magellanic Cloud, a dwarf companion galaxy of the Milky Way. 

Previous observations suggested that R136a1 had a mass somewhere between 250 to 320 times the mass of the Sun. The new Zorro observations, however, indicate that this giant star may be only 170 to 230 times the mass of the Sun. Even with this lower estimate, R136a1 still qualifies as the most massive known star. 

Astronomers are able to estimate a star's mass by comparing its observed brightness and temperature with theoretical predictions. The sharper Zorro image allowed NSF's NOIRLab astronomer Venu M. Kalari and his colleagues to more accurately separated the brightness of R136a1 from its nearby stellar companions, which led to a lower estimate of its brightness and therefore its mass.

“Our results show us that the most massive star we currently know is not as massive as we had previously thought,” explained Kalari, lead author of the paper announcing this result. “This suggests that the upper limit on stellar masses may also be smaller than previously thought.”

This result also has implications for the origin of elements heavier than helium in the Universe. These elements are created during the cataclysmicly explosive death of stars more than 150 times the mass of the Sun in events that astronomers refer to as pair-instability supernovae. If R136a1 is less massive than previously thought, the same could be true of other massive stars and consequently pair instability supernovae may be rarer than expected.

The star cluster hosting R136a1 has previously been observed by astronomers using the NASA/ESA Hubble Space Telescope and a variety of ground-based telescopes, but none of these telescopes could obtain images sharp enough to pick out all the individual stellar members of the nearby cluster.

Gemini South’s Zorro instrument was able to surpass the resolution of previous observations by using a technique known as speckle imaging, which enables ground-based telescopes to overcome much of the blurring effect of Earth’s atmosphere [1]. By taking many thousands of short-exposure images of a bright object and carefully processing the data, it is possible to cancel out almost all this blurring [2]. This approach, as well as the use of adaptive optics, can dramatically increase the resolution of ground-based telescopes, as shown by the team’s sharp new Zorro observations of R136a1 [3].

“This result shows that given the right conditions an 8.1-meter telescope pushed to its limits can rival not only the Hubble Space Telescope when it comes to angular resolution, but also the James Webb Space Telescope,” commented Ricardo Salinas, a co-author of this paper and the instrument scientist for Zorro. “This observation pushes the boundary of what is considered possible using speckle imaging.”

“We began this work as an exploratory observation to see how well Zorro could observe this type of object,” concluded Kalari. “While we urge caution when interpreting our results, our observations indicate that the most massive stars may not be as massive as once thought.”

Zorro and its twin instrument `Alopeke are identical imagers mounted on the Gemini South and Gemini North telescopes, respectively. Their names are the Hawaiian and Spanish words for “fox” and represent the telescopes’ respective locations on Maunakea in Hawai‘i and on Cerro Pachón in Chile. These instruments are part of the Gemini Observatory’s Visiting Instrument Program, which enables new science by accommodating innovative instruments and enabling exciting research. Steve B. Howell, current chair of the Gemini Observatory Board and senior research scientist at the NASA Ames Research Center in Mountain View, California, is the principal investigator on both instruments. 

“Gemini South continues to enhance our understanding of the Universe, transforming astronomy as we know it. This discovery is yet another example of the scientific feats we can accomplish when we combine international collaboration, world-class infrastructure, and a stellar team,” said NSF Gemini Program Officer Martin Still.

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Notes

[1] The blurring effect of the atmosphere is what makes stars twinkle at night, and astronomers and engineers have devised a variety of approaches to dealing with atmospheric turbulence. As well as placing observatories at high, dry sites with stable skies, astronomers have equipped a handful of telescopes with adaptive optics systems, assemblies of computer-controlled deformable mirrors and laser guide stars that can correct for atmospheric distortion. In addition to speckle imaging, Gemini South is able to use its Gemini Multi-Conjugate Adaptive Optics System to counteract the blurring of the atmosphere.

[2] The individual observations captured by Zorro had exposure times of just 60 milliseconds, and 40,000 of these individual observations of the R136 cluster were captured over the course of 40 minutes. Each of these snapshots is so short that the atmosphere didn’t have time to blur any individual exposure, and by carefully combining all 40,000 exposures the team could build up a sharp image of the cluster.

[3] When observing in the red part of the visible electromagnetic spectrum (about 832 nanometers), the Zorro instrument on Gemini South has an image resolution of about 30 milliarcseconds. This is slightly better resolution than NASA/ESA/CSA’s James Webb Space Telescope and about three-times sharper resolution achieved by the Hubble Space Telescope at the same wavelength.

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More Information

This research was presented in the paper “Resolving the core of R136 in the optical” to appear in The Astrophysical Journal.

The team is composed of Venu M. Kalari (Gemini Observatory/NSF's NOIRLab and Departamento de Astronomia, Universidad de Chile), Elliott P. Horch (Department of Physics, Southern Connecticut State University), Ricardo Salinas (Gemini Observatory/NSF's NOIRLab), Jorick S. Vink (Armagh Observatory and Planetarium), Morten Andersen (Gemini Observatory/NSF's NOIRLab and the European Southern Observatory), Joachim M. Bestenlehner (Department of Physics and Astronomy, University of Sheffield), and Monica Rubio (Departamento de Astronomia, Universidad de Chile).

NSF’s NOIRLab (National Optical-Infrared Astronomy Research Laboratory), the US center for ground-based optical-infrared astronomy, operates the international Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), Kitt Peak National Observatory (KPNO), Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and Vera C. Rubin Observatory (operated in cooperation with the Department of Energy’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona. The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O'odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.

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Links

• Research paper
• Photos Gemini South
• Videos of Gemini South

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Contacts:

Venu M. Kalari
Astronomer
NSF’s NOIRLab
Email: venu.kalari@noirlab.edu

Charles Blue
Public Information Officer
NSF’s NOIRLab
Tel: +1 202 236 6324
Email: charles.blue@noirlab.edu

Source: NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab)/News

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ALMA’s 2014 Ground-Breaking HL Tau Results Have Appeared in Over 1,000 Scientific Papers in Less Than a Decade

ALMA image of the young star HL Tau and its protoplanetary disk. This best image ever of planet formation reveals multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas. Credit: ALMA(ESO/NAOJ/NRAO); C. Brogan, B. Saxton (NRAO/AUI/NSF). Hi-Res File

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ALMA’s 2014 Ground-Breaking HL Tau Results Have Appeared in Over 1,000 Scientific Papers in Less Than a Decade

Ground-breaking 2014 HL Tau observational data from the Atacama Large Millimeter/submillimeter Array (ALMA) has been cited in more than 1,000 scientific studies in the past 7.5 years, aiding in major breakthroughs in scientists’ understanding of planet formation. The milestone comes as engineers at the U.S. National Science Foundation’s National Radio Astronomy Observatory (NRAO) embark on ambitious upgrades to the receivers responsible for the clarity of initial observations.

During science verification testing of ALMA’s then-new high-resolution capabilities in 2014, astronomers turned the telescope on HL Tau, a very young star system located 450 light years away from Earth in the constellation Taurus. The resulting image uncovered astonishing details in the planet-forming disk surrounding the Sun-like star and laid the foundation for what has become nearly a decade of increasingly revelatory research. “When we were planning the first ALMA Long Baseline Campaign in 2014, targets were chosen for a range of science categories that were bright and well-studied at lower angular resolution, and that might show, as yet unrevealed, structure at higher angular resolution,” said Crystal Brogan, an astronomer at NRAO and the lead author of the original results paper, which published in The Astrophysical Journal in 2015 and was made possible by a wide range of scientists and engineers across the global ALMA collaboration. “For the protoplanetary disk topic, we were anxious about the potential that we would see little to nothing, certainly nothing spectacular. At that time, there was little indication that there would be much substructure in disk morphology at this relatively young stage of protoplanetary disk evolution. In other words, we feared it could be a flop.”

Ultimately, scientists unveiled not only the best image ever produced using ALMA, but also the clearest picture at the time of planet formation, with detail previously available only in computer simulations and artists’ conceptions. The never-before-seen features in the young star system— including multiple concentric rings separated by clearly defined gaps that were revealed in even greater detail by NSF’s Karl G. Jansky Very Large Array (VLA) in 2016>— are now considered hallmarks of planet formation. “The extraordinary level of substructure that we observed in HL Tau, that could only be revealed by ALMA’s longest baselines, has changed the paradigm of protoplanetary disk formation, evolution and ultimately our understanding of planet formation, forever,” said Brogan. “The remarkable number of papers to date is a direct consequence of its scientific impact.” Similar substructure has now been observed in a wide range of protoplanetary disks with more being observed by ALMA every year. However, HL Tau will forever be the first.”

Stuartt Corder, Deputy Director of ALMA, and a co-author of the original results paper added, “The result was truly moving, beautiful as well as profound. Hard work over decades, plus a dramatic sprint to finish the infrastructure in the middle of 2014, enabled this dramatic and transformational result.”

In addition to providing evidence for long-held theories of planet formation, the 2014 observations of HL Tau opened new windows on the Universe for both professional scientists and aspiring astronomers alike. Todd Hunter, an astronomer at NRAO and a co-author of the original results paper said, “Eighty-three of these citations are from PhD theses, meaning that the careers of an entire generation of young astronomers have been influenced by it.” Hunter added thatforthcoming NSF-supported upgrades to ALMA’s 1.3mm (Band 6) receivers— which were developed at NRAO’s Central Development Laboratory (CDL) and were instrumental in capturing the now-famous images— will further increase the telescope’s capabilities to reveal the secrets of how star systems evolve and planets are formed. “ALMA has recently embarked on a Wideband Sensitivity Upgrade to improve the sensitivity and spectral grasp of the observatory, which will include the development and deployment of more powerful digital signal processing technology. These combined upgrades are essential to enable the next fundamental leap forward in understanding planet formation, as they will vastly increase the number of molecules that can be studied in detail in a single observation of a circumstellar disk”

To date, the 2014 HL Tau results have been cited in 1,013 scientific papers.

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About NRAO

The National Radio Astronomy Observatory (NRAO) is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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

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

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Media Contact:

Amy C. Oliver
Public Information Officer, ALMA
Public Information & News Manager, NRAO
+1 434 242 9584
aoliver@nrao.edu

Source: National Radio Astronomy Observatory (NRAO)/News

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NGC 4424: NASA Telescopes Capture Stellar Delivery Service for Black Hole

NGC 4424
Credit: X-ray: NASA/CXC/Swinburne Univ. of Technology/A. Graham et al.;
Optical: NASA/ESA/STScI

JPEG (117.8 kb) - Large JPEG (5.1 MB) - Tiff (26.8 MB) - More Images

A Tour of NGC 4424 - More Videos

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Astronomers may have witnessed a galaxy’s black hole delivery system in action. A new study using data from NASA’s Chandra X-ray Observatory and Hubble Space Telescope outlines how a large black hole may have been delivered to the spiral galaxy NGC 4424 by another, smaller galaxy.

NGC 4424 is located about 54 million light-years from Earth in the Virgo galaxy cluster. The main panel of this image, which has been previously released, shows a wide-field view of this galaxy in optical light from Hubble. The image is about 45,000 light-years wide. The center of this galaxy is expected to host a large black hole estimated to contain a mass between about 60,000 and 100,000 Suns. There are also likely to be millions of stellar-mass black holes, which contain between about 5 and 30 solar masses, spread throughout the galaxy.

The inset features a close-up view of NGC 4424 that shows Chandra X-ray data (blue), plus infrared data from Hubble (red) that has had infrared light from a model of NGC 4424 subtracted from the image to show other faint features. This inset image is about 1,160 light-years across. The elongated red object is a cluster of stars that the authors of the new study have nicknamed “Nikhuli,” a name relating to the Tulini festive period of celebrating and wishing for a rich harvest. This name is taken from the Sumi language from the Indian state of Nagaland. The Chandra data shows a point source of X-rays.

Close-up view of NGC 4424
Credit: X-ray: NASA/CXC/Swinburne Univ. of Technology/A. Graham et al.;
Optical: NASA/ESA/STScI

The researchers determined Nikhuli is likely the center of a small galaxy that has had most of its stars stripped away as it collides with the larger galaxy NGC 4424. Nikhuli has also been stretched out by gravitational forces as it falls towards the center of NGC 4424, giving it an elongated shape. Currently, Nikhuli is about 1,300 light-years from the center of NGC 4424, or about 20 times closer than the Earth is to the Milky Way’s giant black hole.

One possible explanation for the Chandra X-ray source in the inset is that matter from Nikhuli is falling rapidly into a stellar-mass black hole. However, because these smaller black holes are expected to be rare in a cluster the size of Nikhuli, the authors argue it is more likely from material falling slowly onto a more massive black hole weighing between about 40,000 and 150,000 Suns. This is similar to the expected size of the black hole in the center of NGC 4424. These results imply that Nikhuli is likely acting as a delivery system for NGC 4424’s supply of black holes, in this case bringing along a massive one. If the center of NGC 4424 contains a massive black hole, Nikhuli’s massive black hole should end up orbiting it. The distance separating the pair should then shrink until gravitational waves are produced and the two massive black holes merge with each other.

A paper describing these results appeared in the December 2021 issue of The Astrophysical Journal, and a preprint is available online. The authors of the study are Alister Graham (Swinburne Astronomy Online, Australia), Roberto Soria (University of the Chinese Academy of Sciences in Beijing, China), Bogdan Ciambur (The Paris Observatory, France), Benjamin Davis (New York University in Abu Dhabi, United Arab Emirates), and Douglas Swartz (NASA’s Marshall Space Flight Center in Huntsville, Alabama). 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: NASA Telescopes Capture Stellar Delivery Service for Black Hole

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Fast Facts for NGC 4424:

Scale: Main image is about 2.9 arcmin (45,100 light-years) across. The inset image is about 4.5 arcsec (1,160 light-years) across.

Category: Black Holes, Groups & Clusters of Galaxies
Coordinates (J2000): RA 12h 27m 11.6s | Dec +09° 25´ 14.32"
Constellation: Virgo
Observation Date: April 4, 2017
Observation Time: 4 hours 8 minutes
Obs. ID: 19408
Instrument: ACIS
References: Graham, A. et al., 2021, ApJ, 923, 146.; arXiv:2112.05318
Color Code: X-ray: blue; Optical: red, green, blue
Distance Estimate: About 53.6 million light-years

Source:  NASA’s Chandra X-ray Observatory

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