Institute of Astronomy

Astronomy News

How Venus keeps its cool

16 November 2022 - 11:52am

Nature, Published online: 15 November 2022; doi:10.1038/d41586-022-03711-7

Earth’s planetary twin leaks heat into space from geologically active regions.

How to tell the difference between a regular black hole and a wormhole

16 November 2022 - 11:51am

Physicists have worked out how to see whether a black hole is actually a wormhole that could theoretically be travelled through – but we can’t tell yet with the black holes we have observed

Study of ‘polluted’ white dwarfs finds that stars and planets grow together

15 November 2022 - 9:46am

A study of some of the oldest stars in the Universe suggests that the building blocks of planets like Jupiter and Saturn begin to form while a young star is growing. It had been thought that planets only form once a star has reached its final size, but new results, published in the journal Nature Astronomy, suggest that stars and planets ‘grow up’ together.

The research, led by the University of Cambridge, changes our understanding of how planetary systems, including our own Solar System, formed, potentially solving a major puzzle in astronomy.

“We have a pretty good idea of how planets form, but one outstanding question we’ve had is when they form: does planet formation start early, when the parent star is still growing, or millions of years later?” said Dr Amy Bonsor from Cambridge’s Institute of Astronomy, the study’s first author.

To attempt to answer this question, Bonsor and her colleagues studied the atmospheres of white dwarf stars – the ancient, faint remnants of stars like our Sun – to investigate the building blocks of planet formation. The study also involved researchers from the University of Oxford, the Ludwig-Maximilians-Universität in Munich, the University of Groningen and the Max Planck Institute for Solar System Research, Gottingen.

“Some white dwarfs are amazing laboratories, because their thin atmospheres are almost like celestial graveyards,” said Bonsor.

Normally, the interiors of planets are out of reach of telescopes. But a special class of white dwarfs – known as ‘polluted’ systems – have heavy elements such as magnesium, iron, and calcium in their normally clean atmospheres.

These elements must have come from small bodies like asteroids left over from planet formation, which crashed into the white dwarfs and burned up in their atmospheres. As a result, spectroscopic observations of polluted white dwarfs can probe the interiors of those torn-apart asteroids, giving astronomers direct insight into the conditions in which they formed.

Planet formation is believed to begin in a protoplanetary disc – made primarily of hydrogen, helium, and tiny particles of ices and dust – orbiting a young star. According to the current leading theory on how planets form, the dust particles stick to each other, eventually forming larger and larger solid bodies. Some of these larger bodies will continue to accrete, becoming planets, and some remain as asteroids, like those that crashed into the white dwarfs in the current study.

The researchers analysed spectroscopic observations from the atmospheres of 200 polluted white dwarfs from nearby galaxies. According to their analysis, the mixture of elements seen in the atmospheres of these white dwarfs can only be explained if many of the original asteroids had once melted, which caused heavy iron to sink to the core while the lighter elements floated on the surface. This process, known as differentiation, is what caused the Earth to have an iron-rich core.

“The cause of the melting can only be attributed to very short-lived radioactive elements, which existed in the earliest stages of the planetary system but decay away in just a million years,” said Bonsor. “In other words, if these asteroids were melted by something which only exists for a very brief time at the dawn of the planetary system, then the process of planet formation must kick off very quickly.”

The study suggests that the early-formation picture is likely to be correct, meaning that Jupiter and Saturn had plenty of time to grow to their current sizes.

“Our study complements a growing consensus in the field that planet formation got going early, with the first bodies forming concurrently with the star,” said Bonsor. “Analyses of polluted white dwarfs tell us that this radioactive melting process is a potentially ubiquitous mechanism affecting the formation of all extrasolar planets.

“This is just the beginning – every time we find a new white dwarf, we can gather more evidence and learn more about how planets form. We can trace elements like nickel and chromium and say how big an asteroid must have been when it formed its iron core. It’s amazing that we’re able to probe processes like this in exoplanetary systems.”

Amy Bonsor is a Royal Society University Research Fellow at the University of Cambridge. The research was supported in part by the Royal Society, the Simons Foundation, and the European Research Council.

 

Reference:
Amy Bonsor et al. ‘Rapid formation of exoplanetesimals revealed by white dwarfs.’ Nature Astronomy (2022). DOI: 10.1038/s41550-022-01815-8

A team of astronomers have found that planet formation in our young Solar System started much earlier than previously thought, with the building blocks of planets growing at the same time as their parent star.

Some white dwarfs are amazing laboratories, because their thin atmospheres are almost like celestial graveyardsAmy BonsorAmanda SmithStudy of ‘polluted’ white dwarfs finds that stars and planets grow together


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World’s largest solar telescope array almost complete

14 November 2022 - 9:15am

Nature, Published online: 14 November 2022; doi:10.1038/d41586-022-03595-7

China’s Daocheng Solar Radio Telescope is among a suite of instruments the country has built in the past three years to study the Sun.

ESO images a wondrous star factory to mark 60 years of collaboration

11 November 2022 - 9:55am
For the past 60 years the European Southern Observatory (ESO) has been enabling scientists worldwide to discover the secrets of the Universe. We mark this milestone by bringing you a spectacular new image of a star factory, the Cone Nebula, taken with ESO’s Very Large Telescope (VLT).

NASA’s MAVEN Observes Martian Light Show Caused by Major Solar Storm

11 November 2022 - 9:54am
Portal origin URL: NASA’s MAVEN Observes Martian Light Show Caused by Major Solar StormPortal origin nid: 483867Published: Wednesday, November 9, 2022 - 15:00Featured (stick to top of list): noPortal text teaser: For the first time in its eight years orbiting Mars, NASA’s MAVEN mission witnessed two different types of ultraviolet aurorae simultaneously, the result of solar storms that began on Aug. 27.Portal image: This illustration shows NASA's MAVEN spacecraft flying over Mars.

Seeing the gravitational wave universe

11 November 2022 - 9:53am
Science, Volume 378, Issue 6620, Page 592-593, November 2022.

The discovery and scientific potential of fast radio bursts

11 November 2022 - 9:52am
Science, Volume 378, Issue 6620, November 2022.

Superfluid system hosts early-Universe dynamics

10 November 2022 - 10:30am

Nature, Published online: 09 November 2022; doi:10.1038/d41586-022-03557-z

A fluid of ultracold atoms has exhibited quantum dynamics similar to those thought to have existed moments after the Big Bang — ushering in a new era of laboratory exploration of the early Universe.

Shock cooling of a red-supergiant supernova at redshift 3 in lensed images

10 November 2022 - 10:29am

Nature, Published online: 09 November 2022; doi:10.1038/s41586-022-05252-5

The early stages of a lensed supernova at redshift 3 are found in images taken by the Hubble Space Telescope, with observations beginning from around 5.8 hours after the explosion.

Snapshots capture the early stages of a distant stellar explosion

10 November 2022 - 10:29am

Nature, Published online: 09 November 2022; doi:10.1038/d41586-022-03330-2

Analyses of archival imaging data from the Hubble Space Telescope in 2010 reveal multiple images of a star that exploded about 11.5 billion years ago. An image sequence starting 6 hours after the explosion shows the supernova cooling rapidly during its very early phases.

Applications Now Open for the NASA Jack Eddy Postdoctoral Fellowships

10 November 2022 - 10:28am

The 2023 call for applications to the NASA Jack Eddy Postdoctoral Fellowships is open. This fellowship is sponsored by the NASA Living With a Star (LWS) program, in partnership with Cooperative Programs for the Advancement of Earth System Science (CPAESS) and the University Corporation for Atmospheric Research (UCAR). The fellowship is designed to train the next generation of researchers in the emerging interdisciplinary field of Heliophysics.

Heliophysics embraces all aspects of the Sun-solar system, and includes many of the basic physical processes found in the laboratory, the solar system, and throughout the universe. These processes generally involve the interactions of ionized gases (plasmas) with electro-magnetic and gravitational fields, and to some extent with neutral matter. The physical domain of heliophysics ranges from deep inside the Sun to the beginning of interstellar medium as well as planetary atmospheres including Earth’s upper atmosphere. Within this broad science discipline, LWS is a program designed to develop the scientific understanding required for the nation to address effectively those aspects of the Sun-Earth system that affect life and society.

This year, up to 5 fellows will be appointed. Find out more and apply by Jan. 20, 2023: heliophysics.ucar.edu/jack-eddy/recruitment-announcement 

 

News Article Type: Homepage ArticlesPublished: Wednesday, November 9, 2022 - 09:43

Hubble Captures 3 Faces of Evolving Supernova in Early Universe

10 November 2022 - 10:28am
Portal origin URL: Hubble Captures 3 Faces of Evolving Supernova in Early UniversePortal origin nid: 483871Published: Wednesday, November 9, 2022 - 11:00Featured (stick to top of list): noPortal text teaser: Three different moments in a far-off supernova explosion were captured in a single snapshot by NASA’s Hubble Space Telescope. The star exploded more than 11 billion years ago, when the universe was less than a fifth of its current age of 13.8 billion years.Portal image: One large panel and four smaller panels with the label “Galaxy Cluster Abell 370.” The image is a field of many dozens of white, yellow, red, and blue galaxies of various sizes and shapes.

A miniature universe shows particles may emerge out of empty space

10 November 2022 - 10:27am

A first-of-its-kind experiment simulating the cosmos with ultracold potassium atoms suggests that in a curved, expanding universe pairs of particles pop up out of empty space

Astronomers saw a distant supernova less than 6 hours after it blew up

10 November 2022 - 10:27am

The Hubble Space Telescope has captured a distant star exploding earlier than ever before, allowing astronomers to watch the first eight days of a star’s violent death

Total lunar eclipse bathes moon in red glow

9 November 2022 - 2:37pm

It was visible from North America and the Pacific - but Europe will have to wait until 2025.

Sounds of the stars: how scientists are listening in on space

9 November 2022 - 2:36pm

Nature, Published online: 09 November 2022; doi:10.1038/d41586-022-03597-5

In astronomy, the use of sound instead of light is breaking down barriers to participation and providing insight into the Universe.

We may finally know how impossible stars at our galaxy's centre formed

9 November 2022 - 2:35pm

The centre of the Milky Way is home to more than 100 young stars that shouldn’t exist. Researchers may have now finally figured out how they formed

How a famous black hole makes its brilliant X-rays

7 November 2022 - 9:03pm

Nature, Published online: 03 November 2022; doi:10.1038/d41586-022-03536-4

Scientists trace the source of the dazzling X-rays emanating from Cygnus X-1, the first recognized black hole.