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JWST finds that ancient galaxies contain fewer stars than we expected

Astronomy News - 11 January 2023 - 3:26pm

A group of ancient galaxies examined by the James Webb Space Telescope contain an order of magnitude fewer stars than expected and they are strangely dim

Colliding neutron stars ring in a clue to puzzle of extreme matter

Astronomy News - 10 January 2023 - 10:12am

Nature, Published online: 09 January 2023; doi:10.1038/d41586-022-04580-w

The pitch of oscillations detected in the γ-rays that are emitted when neutron stars collide could provide insight into the hottest and densest matter in the Universe — revealing physics that cannot be studied with terrestrial experiments.

Early Release Science of the exoplanet WASP-39b with JWST NIRCam

Astronomy News - 10 January 2023 - 10:12am

Nature, Published online: 09 January 2023; doi:10.1038/s41586-022-05590-4

Early Release Science of the exoplanet WASP-39b with JWST NIRCam

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Astronomy News - 10 January 2023 - 10:11am

Nature, Published online: 09 January 2023; doi:10.1038/s41586-022-05677-y

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Kilohertz quasiperiodic oscillations in short gamma-ray bursts

Astronomy News - 10 January 2023 - 10:11am

Nature, Published online: 09 January 2023; doi:10.1038/s41586-022-05497-0

Two signals identified in short gamma-ray bursts from archival Burst and Transient Source Experiment data show kilohertz quasiperiodic oscillations, implying the ringing of a hypermassive neutron star before collapsing to a black hole.

NASA’s Webb Telescope Reveals Links Between Galaxies Near and Far

Astronomy News - 10 January 2023 - 10:11am
Portal origin URL: NASA’s Webb Telescope Reveals Links Between Galaxies Near and FarPortal origin nid: 484905Published: Monday, January 9, 2023 - 13:15Featured (stick to top of list): noPortal text teaser: A new analysis of distant galaxies imaged by NASA’s James Webb Space Telescope shows that they are extremely young and share some remarkable similarities to “green peas,” a rare class of small galaxies in our cosmic backyard.Portal image: Galaxies of different shapes, sizes, and colors appear against the black backdrop of space. Three white boxes appear one at a time, showing the locations of a trio of small, faint, red galaxies seen as they were up to 13.1 billion years ago.

NASA’s Retired Compton Mission Reveals Superheavy Neutron Stars

Astronomy News - 10 January 2023 - 10:10am
Portal origin URL: NASA’s Retired Compton Mission Reveals Superheavy Neutron StarsPortal origin nid: 484924Published: Monday, January 9, 2023 - 17:15Featured (stick to top of list): noPortal text teaser: Signals found in archival observations of powerful explosions called short gamma-ray bursts indicate the brief existence of a supersized neutron star before it collapsed into a black hole.Portal image: At the center of a swirl of pale blue arcs, two white spheres representing orbiting neutron stars begin to merge in this illustration.

NASA Science To Be Featured at American Astronomical Society Meeting

Astronomy News - 7 January 2023 - 2:02pm
Portal origin URL: NASA Science To Be Featured at American Astronomical Society MeetingPortal origin nid: 484925Published: Friday, January 6, 2023 - 10:00Featured (stick to top of list): noPortal text teaser: Experts will discuss new research from NASA missions at the 241st meeting of the American Astronomical Society (AAS), on topics ranging from the universe’s early galaxies to planets outside our solar system.Portal image: Image of NGC2024 taken by the Hubble Space Telescope

Become a Dark Energy Explorer!

Astronomy News - 7 January 2023 - 2:02pm

Become a Dark Energy Explorer, help map the distant universe and figure out what makes it expand faster and faster!

Dark energy makes the whole universe expand faster and faster! But what causes this spectacular process? Join NASA’s newest citizen science project, Dark Energy Explorers, and help figure out this puzzle.

At Dark Energy Explorers, you’ll look through images of distant galaxies and other data to help build a map of the universe, focusing on the region about 10 billion light years away. The images come from the Hobby-Eberly Telescope Dark Energy Experiment, based at The University of Texas at Austin's McDonald Observatory. Various explanations for dark energy predict different changes in the expansion rate.

Those changes will affect the map in different ways—so your work will help astrophysicists use the map to sort through the possibilities.

Learn More

 

NASA’s Citizen Science Program:
Learn about NASA citizen science projects
Follow on Twitter
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News Article Type: Homepage ArticlesPublished: Friday, January 6, 2023 - 08:35

Astronomers use ‘little hurricanes’ to weigh and date planets around young stars

Astronomy News - 6 January 2023 - 9:34am

Researchers from the University of Cambridge and the Institute for Advanced Study have developed a technique, which uses observations of these ‘hurricanes’ by the Atacama Large Millimeter/submillimetre Array (ALMA) to place some limits on the mass and age of planets in a young star system.

Pancake-like clouds of gases, dust and ice surrounding young stars – known as protoplanetary discs - are where the process of planet formation begins. Through a process known as core accretion, gravity causes particles in the disc to stick to each other, eventually forming larger solid bodies such as asteroids or planets. As young planets form, they start to carve gaps in the protoplanetary disc, like grooves on a vinyl record.

Even a relatively small planet – as small as one-tenth the mass of Jupiter according to some recent calculations – may be capable of creating such gaps. As these ‘super-Neptune’ planets can orbit their star at a distance greater than Pluto orbits the Sun, traditional methods of exoplanet detection cannot be used.

In addition to the grooves, observations from ALMA have shown other distinct structures in protoplanetary discs, such as banana- or peanut-shaped arcs and clumps. It had been thought that at least some of these structures were also driven by planets.

“Something must be causing these structures to form,” said lead author Professor Roman Rafikov from Cambridge’s Department of Applied Mathematics and Theoretical Physics, and the Institute for Advanced Study in Princeton, New Jersey. “One of the possible mechanisms for producing these structures – and certainly the most intriguing one – is that dust particles that we see as arcs and clumps are concentrated in the centres of fluid vortices: essentially little hurricanes that can be triggered by a particular instability at the edges of the gaps carved in protoplanetary discs by planets.”

Working with his PhD student Nicolas Cimerman, Rafikov used this interpretation to develop a method to constrain a planet’s mass or age if a vortex is observed in a protoplanetary disc. Their results have been accepted for publication in two separate papers in the Monthly Notices of the Royal Astronomical Society.

“It’s extremely difficult to study smaller planets that are far away from their star by directly imaging them: it would be like trying to spot a firefly in front of a lighthouse,” said Rafikov. “We need other, different methods to learn about these planets.”

To develop their method, the two researchers first theoretically calculated the length of time it would take for a vortex to be produced in the disc by a planet. They then used these calculations to constrain the properties of planets in discs with vortices, basically setting lower limits on the planet’s mass or age. They call these techniques ‘vortex weighing’ and ‘vortex dating’ of planets.

When a growing planet becomes massive enough, it starts pushing material from the disc away, creating the tell-tale gap in the disc. When this happens, material on the outside of the gap becomes denser than material on the inside of the gap. As the gap gets deeper and the differences in density become large, an instability can be triggered. This instability perturbs the disc and can eventually produce a vortex.

“Over time, multiple vortices can merge together, evolving into one big structure that looks like the arcs we’ve observed with ALMA,” said Cimerman. Since the vortices need time to form, the researchers say their method is like a clock that can help determine the mass and age of the planet.

“More massive planets produce vortices earlier in their development due to their stronger gravity, so we can use the vortices to place some constraints on the mass of the planet, even if we can’t see the planet directly,” said Rafikov.

Using various data points such as spectra, luminosity and motion, astronomers can determine the approximate age of a star. With this information, the Cambridge researchers calculated the lowest possible mass of a planet that could have been in orbit around the star since the protoplanetary disc formed and was able to produce a vortex that could be seen by ALMA. This helped them put a lower limit on the mass of the planet without observing it directly.

By applying this technique to several known protoplanetary discs with prominent arcs, suggestive of vortices, the researchers found that the putative planets creating these vortices must have masses of at least several tens of Earth masses, in the super-Neptune range.

“In my daily work, I often focus on the technical aspects of performing the simulations,” said Cimerman. “It’s exciting when things come together and we can use our theoretical findings to learn something about real systems.”

“Our constraints can be combined with the limits provided by other methods to improve our understanding of planetary characteristics and planet formation pathways in these systems,” said Rafikov. “By studying planet formation in other star systems, we may learn more about how our own Solar System evolved.”

The research was supported in part by the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI).

 

References:
Roman R. Rafikov and Nicolas P. Cimerman. ‘Vortex weighing and dating of planets in protoplanetary discs.’ Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac3692 or DOI: 10.48550/arXiv.2301.01789

Nicolas P. Cimerman and Roman R. Rafikov. ‘Emergence of vortices at the edges of planet-driven gaps in protoplanetary discs.’ Monthly Notices of the Royal Astronomical Society (2022). DOI: 10.1093/mnras/stac3507

Little ‘hurricanes’ that form in the discs of gas and dust around young stars can be used to study certain aspects of planet formation, even for smaller planets which orbit their star at large distances and are out of reach for most telescopes.

It’s extremely difficult to study smaller planets that are far away from their star by directly imaging them: it would be like trying to spot a firefly in front of a lighthouse. We need other, different methods to learn about these planetsRoman RafikovALMA (ESO/NAOJ/NRAO)ALMA image of the protoplanetary disc around HL Tauri


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Serpent in the sky captured with ESO telescope

Astronomy News - 5 January 2023 - 11:11am
A myriad of stars is revealed behind the faint orange glow of the Sh2-54 nebula in this new infrared image. Located in the constellation Serpens, this stunning stellar nursery has been captured in all its intricate detail using the Visible and Infrared Survey Telescope for Astronomy (VISTA) based at ESO’s Paranal Observatory in Chile.

Intracluster light is already abundant at redshift beyond unity

Astronomy News - 5 January 2023 - 11:10am

Nature, Published online: 04 January 2023; doi:10.1038/s41586-022-05396-4

A study of intracluster light (ICL) in ten high-redshift galaxy clusters finds evidence that gradual stripping may not be the dominant mechanism of ICL formation, but may occur alongside the formation and growth of the brightest cluster galaxies, and/or accretion of preprocessed stars.

Hubble Finds That Ghost Light Among Galaxies Stretches Far Back In Time

Astronomy News - 5 January 2023 - 11:00am
Portal origin URL: Hubble Finds That Ghost Light Among Galaxies Stretches Far Back In TimePortal origin nid: 484852Published: Wednesday, January 4, 2023 - 11:00Featured (stick to top of list): noPortal text teaser: In giant clusters of hundreds or thousands of galaxies, innumerable stars wander among the galaxies like lost souls, emitting a ghostly haze of light.Portal image: Two images. Left: yellow-orange galaxies, in blue halo (intracluster light). Right: 2 elongated blueish, irregular-shaped objects, several small yellow-orange galaxies. Between 2 elongated objects: bright spot in a blue halo (intracluster light).

Gravitational wave hunters will get an ultracool new tool in 2023

Astronomy News - 2 January 2023 - 12:47pm

We have been detecting gravitational waves since 2015, but there is still much more to learn. The Matter-wave Laser Interferometric Gravitation Antenna will use ultracold atoms to spot ripples in space-time at lower frequencies than ever before

Strangely strong interstellar meteorites may come from supernovae

Astronomy News - 2 January 2023 - 12:47pm

The two interstellar meteorites identified so far seem to be significantly stronger than local meteorites, which may mean they formed in supernovae

James Webb telescope: Amazing images show the Universe as never before

Astronomy News - 26 December 2022 - 7:36pm

It's a year since the James Webb telescope launched, and we've marvelled at its pictures ever since.

JWST captured the most thrilling and inspiring space images of 2022

Astronomy News - 26 December 2022 - 7:35pm

The launch of the much-delayed James Webb Space Telescope finally paid off in 2022, as the orbiting observatory delivered jaw-dropping pictures throughout the year

Moon Water Imager Integrated With NASA’s Lunar Trailblazer

Astronomy News - 24 December 2022 - 1:55pm
Portal origin URL: Moon Water Imager Integrated With NASA’s Lunar TrailblazerPortal origin nid: 484776Published: Thursday, December 22, 2022 - 10:15Featured (stick to top of list): noPortal text teaser: JPL’s cutting-edge instrument, which will provide insights into the lunar water cycle and composition of the Moon’s surface, has been incorporated into the small satellite.Portal image: Engineers work on the JPL-developed High-resolution Volatiles and Minerals Moon Mapper

We saw the supermassive black hole at the centre of our galaxy in 2022

Astronomy News - 24 December 2022 - 1:53pm

Astronomers using the Event Horizon Telescope released a picture in May of Sagittarius A*, the black hole at the centre of the Milky Way

How Vera C. Rubin telescope could halve interference from satellites

Astronomy News - 24 December 2022 - 1:52pm

A telescope at the Vera C. Rubin Observatory could cut satellite interference in its images by half by sacrificing about 10 per cent of the time spent observing the night sky