Twisted Physics: Astronomers Solve 30-Year-Old Stellar Mystery

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wisted Physics: Astronomers Solve 30-Year-Old Stellar Mystery

This artist's illustration shows the twisted, funnel-shaped magnetic field (represented by white spiral lines) that ALMA detected wrapped around the gas outflow streaming from a young star embedded in the NGC 1333 IRAS 4A. New data revealed this ring-shaped structure in unprecedented detail, confirming a decades-old prediction of how magnetic fields launch and shape powerful jets from young stars. redit: NSF/AUI/NSF NRAO/M. Weiss. Hi-Res File

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ALMA Observations of a Protostars’ Twisted Outflow Finally Shows the Magnetic Fields Scientists Predicted — But Couldn’t Prove

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), of which the U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO) is a partner, have captured the first direct, high-resolution images of a magnetic field wrapped tightly around the outflow of gas streaming away from a forming star — evidence that solves a decades-old puzzle about how young stars sculpt the powerful jets that form them.

The findings, from a research team led by Tao-Chung Ching, a former Jansky Fellow at the NSF NRAO, focus on NGC 1333 IRAS 4A, a young double-star system embedded in the Perseus molecular cloud, roughly 960 light-years from Earth.

An “invisible magnetic funnel” made visible by ALMA

Newborn stars grow by pulling in gas and dust from a surrounding disk of material. As they do, they also blast some of that material back out into space in fast, narrow jets and wider, slower outflows — a process astronomers have long suspected is shaped and powered by magnetic fields twisted into a funnel-like, doughnut shape around the jet.

“For the first time, these ALMA observations have captured this invisible funnel of magnetic fields,” said Ching, “This is exciting because it proves a decades-old theory about how stars, like our own Sun, are born and fire off powerful cosmic jets.”

The team used ALMA’s exceptional resolving power, roughly 30 times sharper than that of earlier telescopes, to measure the faint polarization of carbon monoxide gas radiating from the outflow around IRAS 4A. That polarization signal let the researchers trace the morphology and strength of the magnetic field threading through the outflow at distances of only a few hundred astronomical units (the average distance between the Earth to the Sun) from the young star.

The team found the magnetic field measured a few thousandths of a gauss (modest compared to a household magnet, but immense on the scale of interstellar space) and that it wrapped around the outflow like a coil, running perpendicular to the direction the gas was flowing and matching the outflow’s rotation. That geometry is the signature of a “toroidal” (or donut-shaped) magnetic field, exactly what theoretical models have predicted for decades — but never directly confirmed at this level of detail.

“This study represents the first and most high-resolution observation of milligauss-strength toroidal magnetic fields at a scale of several hundred astronomical units from a protostar,” adds Ching.

“We knew that IRAS 4A was a textbook case: 20 years ago, in a work published in Science in 2006, we found that this region followed the theoretically expected magnetically driven collapse”, says Josep Miquel Girart, co-author and researcher at the Institute of Space Sciences (ICE-CSIC) and the Institute of Space Studies of Catalonia (IEEC).

A new tool for mapping magnetic fields

The team also uncovered an unexpected bonus: a straightforward mathematical relationship, based on the physics principle known as Ampère’s law, linking the twisting of the magnetic field to the electric currents flowing through the gas. Because that relationship follows a predictable, linear pattern, it gives astronomers a new and more direct way to work out the direction of magnetic fields in the clouds of gas and dust where stars are born — a notoriously difficult measurement to make.

Understanding how magnetic fields shape stellar outflows helps astronomers explain a fundamental step in star formation, for how young stars shed excess material and angular momentum so they can continue growing, rather than spinning themselves apart. The same physical process is thought to play out at vastly different scales throughout the Universe, from newborn stars like the one studied here, to the supermassive black holes that power distant galaxies.

Source: National Radio Astronomy Observatory (NRAO)/News

Scientific Paper

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About ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan, together with NRC (Canada), NSTC (Taiwan), ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile, is located on the Chajnantor plateau in northern Chile. ALMA is operated by ESO, the Associated Universities, Inc./National Radio Astronomy Observatory (AUI/NRAO), and the National Astronomical Observatory of Japan (NAOJ).

About NRAO

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

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A chemically rich outflow from a young Sun-like star: A new laboratory for shock chemistry

During the early stages of star formation, material is ejected at high speed from near the forming star forming a bipolar structure referred to as protostellar outflow. Credit: NASA, ESA, CSA, STScI

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A study led by the Center for Astrochemical Studies (CAS) at MPE has revealed an unexpectedly rich chemical inventory in the outflow of the young, Sun-like protostar IRAS 4B1, located about 300 parsecs away in the star-forming region NGC 1333 in the Perseus molecular cloud. So far, there is only one low-mass protostellar outflow in which emission of complex organic molecules has been studied extensively, making IRAS 4B1 a rare and valuable laboratory for exploring how these molecules behave under extreme conditions.

One of the central questions in astrochemistry is how simple interstellar molecules grow into more complex species during the process of star and planet formation. As these processes unfold over millions of years, astronomers rely on snapshots of many systems at different evolutionary stages, using comparisons with theoretical models to trace the chemical evolution.

Protostellar outflows offer a unique window into these transformations. In the earliest stages of star formation, material is ejected from the young forming star at high speed. When this gas collides with the surrounding cloud, it generates shock waves that compress and briefly heat the gas and dust, rapidly altering the chemistry. These shocks can release complex organic molecules - defined as carbon-bearing species containing at least six atoms - that were previously frozen onto dust grains, injecting a burst of rich chemistry into the surrounding region.

Despite their importance, such detections are rare. “While working on a separate PRODIGE project mapping methyl cyanide (CH₃CN) toward IRAS 4B1, I noticed emission that appeared to trace the outflow rather than the hot surroundings of the forming star,” says Laura Busch, a postdoctoral researcher at MPE who led the study. “This made me search the data for more complex molecules – and I found them.”

The PRODIGE observations, carried out with the Northern Extended Millimeter Array (NOEMA), reveal a surprisingly diverse chemical composition in the outflow. “The combination of high sensitivity and broad spectral coverage makes PRODIGE ideally suited to this kind of study,” adds Jaime Pineda, scientist at MPE. “It allows us to detect and map multiple complex molecules simultaneously — something that would otherwise be extremely difficult.”

Maps of molecular emission show that different molecules trace distinct regions within the outflow, indicating variations in temperature and density. Some species are brightest where temperatures are highest, while others originate in cooler zones, reflecting different chemical pathways. These findings provide fresh insight into how complex organic molecules — the precursors of prebiotic chemistry — are processed by shocks during the earliest phases of star formation.

Source: Max Planck Institute for Extraterrestrial Physics (MPE)/Paper of the Month

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The PROtostars & DIsks: Global Evolution (PRODIGE; PIs: P. Caselli and Th. Henning) is a collaboration between the Max Planck Society and the Institut de Radioastromie Millimétrique (IRAM) located in France. The project targeted a total of 30 Class 0/I protostellar systems in the Perseus molecular cloud, with the main goal of studying the kinematics of star formation. The observations cover a broad spectral bandwidth of 16GHz, a unique treat of the NOrthern Extended Millimeter Array (NOEMA) located in the French Alpes and run by IRAM that was used to observe the data, is essential for identifying molecules and study their emission spectra.

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Contacts:

Dr. Laura Busch
Post-Doc
lbusch@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching
Center for Astrochemical Studies

Dr. Jaime Pineda Fornerod
Scientist
Tel: +49 (0)89 30000-3610
Fax: +49 (0)89 30000-3950
jpineda@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics, Garching
Center for Astrochemical Studies

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Publication

L. A. Busch, J. E. Pineda, P. Caselli, D. M. Segura-Cox, S. Narayanan, C. Gieser, M. J. Maureira, T.-H. Hsieh, Y. Lin, M. T. Valdivia-Mena, L. Bouscasse, Th. Henning, D. Semenov, A. Fuente, Y.-R. Chou, L. Mason, P. C. Cortés, L. W. Looney, I. W. Stephens, M. Tafalla, A. Dutrey, W. Kwon, P. Saha

PRODIGE - envelope to disk with NOEMA: VII. (Complex) organic molecules in the NGC1333 IRAS4B1 outflow: A new laboratory for shock chemistry

arXiv

Source | DOI

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Webb peeks into Perseus

A nebula made up of cloudy gas and dust in the form of soft and wispy clouds and, in the centre, thin and highly detailed layers pressed close together. Large, bright stars surrounded by six long points of light are dotted over the image, as well as some small, point-like stars embedded in the clouds. The clouds are lit up in blue close to the stars; orange colours show clouds that glow in infrared light. Credit: ESA/Webb, NASA & CSA, A. Scholz, K. Muzic, A. Langeveld, R. Jayawardhana

This stunning new mosaic of images from the NASA/ESA/CSA James Webb Space Telescope showcases the nearby star-forming cluster, NGC 1333. The nebula is in the Perseus molecular cloud, and located approximately 960 light-years away.

Webb’s superb sensitivity allows astronomers to investigate young objects with extremely low masses. Some of the faintest ‘stars’ in the picture are in fact newly born free-floating brown dwarfs with masses comparable to those of giant planets.

The same cluster was featured as the 33rd anniversary image of the NASA/ESA Hubble Space Telescope in April 2023. Hubble’s image just scratched the surface of this region, because clouds of dust obscure much of the star formation process. Observing with larger aperture and in the infrared part of the spectrum, Webb is capable of peering through the dusty veil to reveal newborn stars, brown dwarfs and planetary mass objects.

The centre of the image presents a deep peek into the heart of the NGC1333 cloud. Across the image we see large patches of orange, which represent gas glowing in the infrared. These so-called Herbig-Haro objects form when ionised material ejected from young stars collides with the surrounding cloud. They are hallmarks of a very active site of star formation.

Many of the young stars in this image are surrounded by disks of gas and dust, which may eventually produce planetary systems. Similar to the young stars in this mosaic, our own Sun and planets formed inside a dusty molecular cloud, 4.6 billion years ago. Our Sun did not form in isolation but as part of a cluster, which was perhaps even more massive than NGC 1333. The cluster in the mosaic, only 1-3 million years old, presents us with an opportunity to study stars like our Sun, as well as brown dwarfs and free-floating planets, in their nascent stages.

The images were captured as part of the Webb observation programme 1202 (PI: A. Scholz) to survey a large portion of NGC 1333. These data constitute the first deep spectroscopic survey of the young cluster, and have identified brown dwarfs down to planetary masses using the observatory’s Near-Infrared Imager and Slitless Spectrograph (NIRISS). The first results from this survey have been accepted for publication in the Astronomical Journal.

Source: ESA

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CC BY 4.0 INT or ESA Standard Licence
(content can be used under either licence)

Space Science

JWST | Webb

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Hubble Celebrates 33rd Anniversary with a Peek into Nearby Star-Forming Region

NGC 1333
Credits: Science: NASA, ESA, STScI
Image Processing: Varun Bajaj (STScI), Joseph DePasquale (STScI), Jennifer Mack (STScI)

Release Images | Release Videos

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Astronomers are celebrating NASA's Hubble Space Telescope's 33rd launch anniversary with an ethereal photo of a nearby star-forming region, NGC 1333. The nebula is in the Perseus molecular cloud, and located approximately 960 light-years away.

Hubble's colorful view, showcased through its unique capability to obtain images from ultraviolet to near-infrared light, unveils an effervescent cauldron of glowing gasses and pitch-black dust stirred up and blown around by several hundred newly forming stars embedded within the dark cloud. Hubble just scratches the surface because most of the star birthing firestorm is hidden behind clouds of fine dust – essentially soot – that are thicker toward the bottom of the image. The blackness in the image is not empty space, but filled with obscuring dust.

To capture this image, Hubble peered through a veil of dust on the edge of a giant cloud of cold molecular hydrogen – the raw material for fabricating new stars and planets under the relentless pull of gravity. The image underscores the fact that star formation is a messy process in our rambunctious universe.

Ferocious stellar winds, likely from the bright blue star at the top of the image, are blowing through a curtain of dust. The fine dust scatters the starlight at blue wavelengths.

Farther down, another bright, super-hot star shines through filaments of obscuring dust, looking like the Sun shining through scattered clouds. A diagonal string of fainter accompanying stars looks reddish because dust is filtering starlight, allowing more of the red light to get through.

The bottom of the picture presents a keyhole peek deep into the dark nebula. Hubble captures the reddish glow of ionized hydrogen. It looks like a fireworks finale, with several overlapping events. This is caused by pencil-thin jets shooting out from newly forming stars outside the frame of view. These stars are surrounded by circumstellar disks, which may eventually produce planetary systems, and powerful magnetic fields that direct two parallel beams of hot gas deep into space, like a double light saber from science fiction films. They sculpt patterns on the hydrogen cocoon, like laser-light-show tracings. The jets are a star's birth announcement.

This view offers an example of the time when our Sun and planets formed inside such a dusty molecular cloud, 4.6 billion years ago. Our Sun didn't form in isolation but was instead embedded inside a mosh pit of frantic stellar birth, perhaps even more energetic and massive than NGC 1333.

Hubble was deployed into orbit around Earth on April 25, 1990, by NASA astronauts aboard the Space Shuttle Discovery. To date, the legendary telescope has taken approximately 1.6 million observations of nearly 52,000 celestial targets. This treasure trove of knowledge about the universe is stored for public access in the Mikulski Archive for Space Telescopes , at the Space Telescope Science Institute in Baltimore, Maryland.

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

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Source: HubbleSite/News

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Spitzer Studies a Stellar Playground With a Long History

A collection of gas and dust over 500 light-years across, the Perseus Molecular Cloud hosts an abundance of young stars. It was imaged here by the NASA's Spitzer Space Telescope.Credit: NASA/JPL-Caltec. › Full image and caption

This image from NASA's Spitzer Space Telescope shows the Perseus Molecular Cloud, a massive collection of gas and dust that stretches over 500 light-years across. Home to an abundance of young stars, it has drawn the attention of astronomers for decades.

Spitzer's Multiband Imaging Photometer (MIPS) instrument took this image during Spitzer's "cold mission," which ran from the spacecraft's launch in 2003 until 2009, when the space telescope exhausted its supply of liquid helium coolant. (This marked the beginning of Spitzer's "warm mission.") Infrared light can't be seen by the human eye, but warm objects, from human bodies to interstellar dust clouds, emit infrared light.

Infrared radiation from warm dust generates much of the glow seen here from the Perseus Molecular Cloud. Clusters of stars, such as the bright spot near the left side of the image, generate even more infrared light and illuminate the surrounding clouds like the Sun lighting up a cloudy sky at sunset. Much of the dust seen here emits little to no visible light (in fact, the dust blocks visible light) and is therefore revealed most clearly with infrared observatories like Spitzer.

On the right side of the image is a bright clump of young stars known as NGC 1333, which Spitzer has observed multiple times. It is located about 1,000 light-years from Earth. That sounds far, but it is close compared to the size of our galaxy, which is about 100,000 light-years across. NGC 1333's proximity and strong infrared emissions made it visible to astronomers using some of the earliest infrared instruments.

This image from NASA'S Spitzer Space Telescope shows the location and apparent size of the Perseus Molecular Cloud in the night sky. Located on the edge of the Perseus Constellation, the collection of gas and dust is about 1,000 light-years from Earth and about 500 light-years wide.

Credit: NASA/JPL-Caltech.  Full image and caption

In fact, some of its stars were first observed in the mid-1980s with the Infrared Astronomical Survey (IRAS), a joint mission between NASA, the United Kingdom and the Netherlands. The first infrared satellite telescope, it observed the sky in infrared wavelengths blocked by Earth's atmosphere, providing the first-ever view of the universe in those wavelengths. 

More than 1,200 peer-reviewed research papers have been written about NGC 1333, and it has been studied in other wavelengths of light, including by the Hubble Space Telescope, which detects mostly visible light, and the Chandra X-Ray Observatory. 

Many young stars in the cluster are sending massive outflows of material - the same material that forms the star - into space. As the material is ejected, it is heated up and smashes into the surrounding interstellar medium. These factors cause the jets to radiate brightly, and they can be seen in close-up studies of the region. This has provided astronomers with a clear glimpse of how stars go from a sometimes-turbulent adolescence into calmer adulthood.

An Evolving Mystery

Other clusters of stars seen below NGC 1333 in this image have posed a fascinating mystery for astronomers: They appear to contain stellar infants, adolescents and adults. Such a closely packed mixture of ages is extremely odd, according to Luisa Rebull, an astrophysicist at NASA's Infrared Science Archive at Caltech-IPAC who has studied NGC 1333 and some of the clusters below it. Although many stellar siblings may form together in tight clusters, stars are always moving, and as they grow older they tend to move farther and farther apart.

This annotated image of the Perseus Molecular Cloud, provided by NASA's Spitzer Space Telescope, shows the location of various star clusters, including NGC 1333.  Credit: NASA/JPL-Caltech..  Full image and caption

Finding such a closely packed mixture of apparent ages doesn't fit with current ideas about how stars evolve. "This region is telling astronomers that there's something we don't understand about star formation," said Rebull. The puzzle presented by this region is one thing that keeps astronomers coming back to it. "It's one of my favorite regions to study," she added. 

Since IRAS's early observations, the region has come into clearer focus, a process that is common in astronomy, said Rebull. New instruments bring more sensitivity and new techniques, and the story becomes clearer with each new generation of observatories. On Jan. 30, 2020, NASA will decommission the Spitzer Space Telescope, but its legacy has paved the way for upcoming observatories, including the James Webb Space Telescope, which will also observe infrared light.

The Spitzer-MIPS data used for this image is at the infrared wavelength of 24 microns. Small gaps along the edges of this image not observed by Spitzer were filled in using 22-micron data from NASA's Wide-Field Infrared Survey Explorer (WISE).

To learn more about Spitzer and how it studies the infrared universe, check out the Spitzer 360 VR experience, now available on the NASA Spitzer channel on YouTube: http://bit.ly/SpitzerVR.

More information about Spitzer is available at the following site(s):   https://www.nasa.gov/mission_pages/spitzer/main

News Media Contact

Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
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Source:   JPL-Caltec/News

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NASA’s Webb Telescope to Search for Young Brown Dwarfs and Rogue Planets

Scientists will use Webb to search the nearby stellar nursery NGC 1333 for its smallest, faintest residents. It is an ideal place to look for very dim, free-floating objects, including those with planetary masses. Credits: NASA/JPL-Caltech/R. A. Gutermuth (Harvard-Smithsonian CfA). Hi-res image

How small are the smallest celestial objects that form like stars, but don't produce their own light? How common are they compared to full-fledged stars? How about “rogue planets,” which formed around stars before being tossed into interstellar space? When NASA’s James Webb Space Telescope launches in 2021, it will shed light on these questions

Answering them will set a boundary between objects that form like stars, which are born out of gravitationally collapsing clouds of gas and dust, and those that form like planets, which are created when gas and dust clump together in a disk around a young star. It will also distinguish among competing ideas about the origins of brown dwarfs, objects with masses between 1% and 8% of the Sun that cannot sustain hydrogen fusion at their cores.

In a study led by Aleks Scholz of the University of St Andrews in the United Kingdom, researchers will use Webb to discover the smallest, faintest residents of a nearby stellar nursery called NGC 1333. Located about 1,000 light-years away in the constellation Perseus, the stellar cluster NGC 1333 is fairly close in astronomical terms. It is also very compact and contains many young stars. These three factors make it an ideal place to study star formation in action, particularly for those interested in very faint, free-floating objects.

“The least massive brown dwarfs identified so far are only five to 10 times heftier than the planet Jupiter,” explained Scholz. “We don’t yet know whether even lower mass objects form in stellar nurseries. With Webb, we expect to identify cluster members as puny as Jupiter for the first time ever. Their numbers relative to heftier brown dwarfs and stars will shed light on their origins and also give us important clues about the star formation process more broadly.”

A Fuzzy Boundary

Very low-mass objects are cool, meaning they emit most of their light in infrared wavelengths. Observing infrared light from ground-based telescopes is challenging because of interference from Earth's atmosphere. Due to its sheer size and ability to see infrared light with unprecedented sensitivity, Webb is ideally suited for finding and characterizing young free-floating objects with masses below five Jupiters.

The distinction between brown dwarfs and giant planets is blurry.

“There are some objects with masses below the 10-Jupiter mark freely floating through the cluster. As they don’t orbit any particular star, we may call them brown dwarfs, or planetary-mass objects, since we don’t know better,” said team member Koraljka Muzic of the University of Lisbon in Portugal. “On the other hand, some massive giant planets may have fusion reactions. And some brown dwarfs may form in a disk.”

There is also the issue of “rogue planets”—objects that form like planets and then later get ejected from their solar systems. These free-floating bodies are doomed to wander between the stars forever.

Dozens at Once

The team will use Webb’s Near Infrared Imager and Slitless Spectrograph (NIRISS) to study these various low-mass objects. A spectrograph breaks the light from a single source into its component colors the way a prism splits white light into a rainbow. That light carries fingerprints produced when material emits or interacts with light. Spectrographs allow researchers to analyze those fingerprints and discover properties like temperature and composition.

NIRISS will give the team simultaneous information for dozens of objects. “That is key. For an unambiguous confirmation of a brown dwarf or rogue planet we need to see the absorption signatures of molecules — water and methane primarily — in the spectra,” explained team member Ray Jayawardhana of Cornell University. “Spectroscopy is time consuming, and being able to observe many objects simultaneously helps enormously. The alternative is to take images first, measure colors, select candidates, and then go and take spectra, which will take much more time and relies on more assumptions.”

This work is being conducted as part of a Webb Guaranteed Time Observations (GTO) program. This program is designed to reward scientists who helped develop the key hardware and software components or technical and interdisciplinary knowledge for the observatory. Jayawardhana has been involved in the design and development of NIRISS, as well as its key science programs, as a core member of the instrument team since 2004.

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

For more information about Webb, visit www.nasa.gov/webb.

By Ann Jenkins
Space Telescope Science Institute
Baltimore, Md.

Editor: Lynn Jenner

Source: NASA/Webb Telescope

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Champions League

NGC 1333

Credit: ESA/Hubble & NASA, K. Stapelfeldt

Within a galaxy hosting around 300 billion stars, here the NASA/ESA Hubble Space Telescope has captured a mere handful or two — just about enough to form a single football team. These stellar “teammates” play under the banner of NGC 1333, the cloud of gas and dust which formed them and that they continue to call home.

NGC 1333 is located about 1000 light-years away in the constellation of Perseus (The Hero). The cool gas and dust concentrated in this region is generating new stars whose light is then reflecting off the surrounding material, lighting it up and making this object’s lingering presence known to us. NGC 1333 is accordingly classified as a reflection nebula.

This image shows just a single region of NGC 1333. Hubble has imaged NGC 1333 more widely before, revealing that the smattering of stars seen here has ample company. Seen in a broader context, this team of stars is but one gathering amongst many in NGC 1333’s celestial Champions League.

Source: ESA/Hubble/Potw

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The smoking gun of a newborn star

2MASS J03285694+3116222
Credit: ESA/Hubble & NASA, K. Stapelfeldt

In this image the NASA/ESA Hubble Space Telescope has captured the smoking gun of a newborn star, the Herbig–Haro objects numbered 7 to 11 (HH 7–11). These five objects, visible in blue in the top centre of the image, lie within NGC 1333, a reflection nebula full of gas and dust found about a thousand light-years away from Earth.

Herbig-Haro objects like HH 7–11 are transient phenomena. Travelling away from the star that created them, at a speed of up to 250 000 kilometres per hour they disappear into nothingness within a few tens of thousands of years. The young star that is the source of HH 7-11 is called SVS 13 and all five objects are moving away from SVS 13 toward the upper left. The current distance between HH 7 and SVS 13 is about 20 000 times the distance between Earth and the Sun.

Herbig–Haro objects are formed when jets of ionised gas ejected by a young star collide with nearby clouds of gas and dust at high speeds. The Herbig-Haro objects visible in this image are no exception to this and were formed when the jets from the newborn star SVS 13 collided with the surrounding clouds. These collisions created the five brilliant clumps of light within the reflection nebula.

Source: ESA/Hubble/Potw

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NASA’s Webb Telescope to Investigate Mysterious Brown Dwarfs

Stellar cluster NGC 1333 is home to a large number of brown dwarfs. Astronomers will use Webb’s powerful infrared instruments to learn more about these dim cousins to the cluster’s bright newborn stars.Credits: NASA/CXC/JPL

Twinkle, twinkle, little star, how I wonder what you are. Astronomers are hopeful that the powerful infrared capability of NASA’s James Webb Space Telescope will resolve a puzzle as fundamental as stargazing itself — what IS that dim light in the sky? Brown dwarfs muddy a clear distinction between stars and planets, throwing established understanding of those bodies, and theories of their formation, into question.

Several research teams will use Webb to explore the mysterious nature of brown dwarfs, looking for insight into both star formation and exoplanet atmospheres, and the hazy territory in-between where the brown dwarf itself exists. Previous work with Hubble, Spitzer, and ALMA have shown that brown dwarfs can be up to 70 times more massive than gas giants like Jupiter, yet they do not have enough mass for their cores to burn nuclear fuel and radiate starlight. Though brown dwarfs were theorized in the 1960s and confirmed in 1995, there is not an accepted explanation of how they form: like a star, by the contraction of gas, or like a planet, by the accretion of material in a protoplanetary disk? Some have a companion relationship with a star, while others drift alone in space.

At the Université de Montréal, Étienne Artigau leads a team that will use Webb to study a specific brown dwarf, labeled SIMP0136. It is a low-mass, young, isolated brown dwarf — one of the closest to our Sun — all of which make it fascinating for study, as it has many features of a planet without being too close to the blinding light of a star. SIMP0136 was the object of a past scientific breakthrough by Artigau and his team, when they found evidence suggesting it has a cloudy atmosphere. He and his colleagues will use Webb’s spectroscopic instruments to learn more about the chemical elements and compounds in those clouds. 

“Very accurate spectroscopic measurements are challenging to obtain from the ground in the infrared due to variable absorption in our own atmosphere, hence the need for space-based infrared observation. Also, Webb allows us to probe features, such as water absorption, that are inaccessible from the ground at this level of precision,” Artigau explains.

Artist’s conception of a brown dwarf, featuring the cloudy atmosphere of a planet and the residual light of an almost-star.

Credits: NASA/ESA/JPL

These observations could lay groundwork for future exoplanet exploration with Webb, including which worlds could support life. Webb’s infrared instruments will be capable of detecting the types of molecules in the atmospheres of exoplanets by seeing which elements are absorbing light as the planet passes in front of its star, a scientific technique known as transit spectroscopy.

“The brown dwarf SIMP0136 has the same temperature as various planets that will be observed in transit spectroscopy with Webb, and clouds are known to affect this type of measurement; our observations will help us better understand cloud decks in brown dwarfs and planet atmospheres in general,” Artigau says.

The search for low-mass, isolated brown dwarfs was one of the early science goals put forward for the Webb telescope in the 1990s, says astronomer Aleks Scholz of the University of St. Andrews. Brown dwarfs have a lower mass than stars and do not “shine” but merely emit the dim afterglow of their birth, and so they are best seen in infrared light, which is why Webb will be such a valuable tool in this research.

Scholz, who also leads the Substellar Objects in Nearby Young Clusters (SONYC) project, will use Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) to study NGC 1333 in the constellation of Perseus. NGC 1333 is a stellar nursery that has also been found to harbor an unusually high number of brown dwarfs, some of them at the very low end of the mass range for such objects – in other words, not much heavier than Jupiter.

"In more than a decade of searching, our team has found it is very difficult to locate brown dwarfs that are less than five Jupiter-masses - the mass where star and planet formation overlap. That is a job for the Webb telescope,” Scholz says. “It has been a long wait for Webb, but we are very excited to get an opportunity to break new ground and potentially discover an entirely new type of planets, unbound, roaming the Galaxy like stars."

Both of the projects led by Scholz and Artigau are making use of Guaranteed Time Observations (GTOs), observing time on the telescope that is granted to astronomers who have worked for years to prepare Webb’s scientific operations
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The James Webb Space Telescope, the scientific complement to NASA's Hubble Space Telescope, will be the premier space observatory of the next decade. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

For more information about the Webb telescope, visit www.nasa.gov/webb or www.webbtelescope.org

By Leah Ramsay
Space Telescope Science Institute, Baltimore, Md.

Editor: Lynn Jenner
 

Source: NASA/Webb Telescope

NGC 1333: Stellar Sparklers That Last

NGC 1333
Credit X-ray: NASA/CXC/SAO/S.Wolk et al; 
Optical: DSS & NOAO/AURA/NSF; Infrared: NASA/JPL-Caltech

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A Tour of NGC 6388

While fireworks only last a short time here on Earth, a bundle of cosmic sparklers in a nearby cluster of stars will be going off for a very long time. NGC 1333 is a star cluster populated with many young stars that are less than 2 million years old, a blink of an eye in astronomical terms for stars like the Sun expected to burn for billions of years.

This new composite image combines X-rays from NASA's Chandra X-ray Observatory (pink) with infrared data from the Spitzer Space Telescope (red) as well as optical data from the Digitized Sky Survey and the National Optical Astronomy Observatory Mayall 4-meter telescope on Kitt Peak (red, green, blue). The Chandra data reveal 95 young stars glowing in X-ray light, 41 of which had not been identified previously using infrared observations with Spitzer because they lacked infrared emission from a surrounding disk.

To make a detailed study of the X-ray properties of young stars, a team of astronomers, led by Elaine Winston from the University of Exeter, analyzed both the Chandra X-ray data of NGC 1333, located about 780 light years from Earth, and of the Serpens cloud, a similar cluster of young stars about 1100 light years away. They then compared the two datasets with observations of the young stars in the Orion Nebula Cluster, perhaps the most-studied young star cluster in the Galaxy.

The researchers found that the X-ray brightness of the stars in NGC 1333 and the Serpens cloud depends on the total brightness of the stars across the electromagnetic spectrum, as found in previous studies of other clusters. They also found that the X-ray brightness mainly depends on the size of the star. In other words, the bigger the stellar sparkler, the brighter it will glow in X-rays.

These results were published in the July 2010 issue of the Astronomical Journal and are available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado.

Fast Facts for NGC 1333:

Scale: Image is 18 arcmin across (about 4 light years)
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 03h 29m 02.00s | Dec +31 20 54.00
Constellation: Perseus
Observation Date: 12 Jul 2000, 05, 11 Jul 2006
Observation Time: 36 hours 7 min (1 day 12 hours 7 min).
Obs. ID: 642, 6436, 6437
Instrument: ACIS
References: Rebull, L.M., 2015, AJ (accepted); arXiv:1504.07564
Color Code: X-ray (Pink); Optical (Red, Green, Blue); Infrared (Red)
Distance Estimate: About 770 light years

Source: NASA’s Chandra X-ray Observatory

"Failed Stars" Galore with One Youngster Only Six Times Heftier than Jupiter

Figure 1: Brown dwarfs in the young star cluster NGC 1333. This photograph combines optical and infrared images taken with the Subaru Telescope. Brown dwarfs newly identified by the SONYC Survey are circled in yellow, while previously known brown dwarfs are circled in white. The arrow points to the least massive brown dwarf known in NGC 1333; it is only about six times heftier than Jupiter. Credit: SONYC Team/Subaru Telescope. Large Image

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1. ‬High resolution Image with all the labels and marks.
‪2. High resolution image with circles and border.
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Figure 2: Spectra of several brown dwarfs in the young star cluster NGC1333, taken with the FMOS instrument on the Subaru Telescope. The spectra show a characteristic peak around 1670nm. Water steam in a brown dwarf's atmosphere absorbs radiation on both sides of the peak. The plot shows that the strength of the water absorption increases in cooler objects (from 3000 to 2200K). FMOS allows astronomers to take spectra for many objects simultaneously, a crucial advantage for the SONYC Survey. Credit: SONYC Team/Subaru Telescope. Large Image

An international team of astronomers has discovered over two-dozen new free-floating brown dwarfs that reside in two young star clusters. One brown dwarf is a lightweight youngster only about six times heftier than Jupiter. What's more, one cluster contains a surprising surplus of brown dwarfs; it harbors half as many of these astronomical oddballs as normal stars. These findings come from deep surveys and extensive follow-up observations using the Subaru Telescope in Hawaii and the Very Large Telescope (VLT) in Chile, two of the world's largest optical-infrared telescopes.

Sometimes described as failed stars, brown dwarfs are unusual celestial objects that straddle the boundary between stars and planets. When young, they glow brightly from the heat of formation, but they eventually cool down and end up with atmospheres that exhibit planet-like characteristics.

During the course of the SONYC (Substellar Objects in Nearby Young Clusters) Survey, astronomers used Subaru Telescope to take extremely deep images of the NGC 1333 (Figure 1) and rho Ophiuchi star clusters at both optical and infrared wavelengths. Once they identified candidate brown dwarfs from their very red colours, the research team verified their nature with spectra taken at Subaru and the VLT. The team's findings are reported in two upcoming papers in the Astrophysical Journal and will be presented this week at a scientific conference in Garching, Germany.

The six-Jupiter-mass brown dwarf found in the NGC 1333 cluster is one of the puniest free-floating objects known. "Its mass is comparable to those of giant planets, yet it doesn't circle a star. How it formed is a mystery," said Aleks Scholz of the Dublin Institute for Advanced Studies in Ireland, lead author of the first paper.

Several other newly identified brown dwarfs in both NGC 1333 (Figure 2) and rho Ophiuchi clusters have masses that are less than 20 times the mass of Jupiter-placing them at the low end of the mass range for known brown dwarfs. "Brown dwarfs seem to be more common in NGC 1333 than in other young star clusters. That difference may be hinting at how different environmental conditions affect their formation," said Koraljka Muzic of the University of Toronto in Canada, lead author of the second paper.

"Our findings suggest once again that objects not much bigger than Jupiter could form the same way as stars do. In other words, nature appears to have more than one trick up its sleeve for producing planetary mass objects," said Ray Jayawardhana of the University of Toronto, who is the principal investigator of the SONYC Survey.

"We could not have made these exciting discoveries if not for the remarkable capabilities of Subaru and the VLT. Instruments that can image large patches of the sky and take hundreds of spectra at once are key to our success," said Motohide Tamura of the National Astronomical Observatory of Japan.

Other co-authors of this work are Vincent Geers of ETH Zurich in Switzerland and Mariangela Bonavita of the University of Toronto.

The papers are to appear in the Astrophysical Journal and can be accessible from the following links:

• Alexander Scholz, Koraljka Muzic, Vincent Geers, Mariangela Bonavita, Ray Jayawardhana, and Motohide Tamura "Substellar Objects in Nearby Young Clusters (SONYC) IV: A Census of Very Low Mass Objects in NGC1333" (link)

• Koraljka Muzic, Alexander Scholz, Vincent Geers, Ray Jayawardhana, and Motohide Tamura "Substellar Objects in Nearby Young Clusters (SONYC) V: New Brown Dwarfs in ρ Ophiuchi" (link)