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Posts Tagged ‘Royal Astronomical Society’

Stretched-Out Solid Exoplanets

December 16, 2014 Leave a comment

Artist’s impression. Credit: Shivam Sikroria

Artist’s impression. Credit: Shivam Sikroria

Astronomers could soon be able to find rocky planets stretched out by the gravity of the stars they orbit, according to a group of researchers in the United States. The team, led by Prabal Saxena of George Mason University, describe how to detect these exotic worlds in a paper in the journal Monthly Notices of the Royal Astronomical Society.

Since the first discovery in 1993, more than 1800 planets have been found in orbit around stars other than our Sun. These ‘exoplanets’ are incredibly diverse, with some gaseous like Jupiter and some mostly rocky like the Earth. The worlds also orbit their stars at very different distances, from less than a million km to nearly 100 billion km away.

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Interactive Dark Matter Could Explain Milky Way’s Missing Satellite Galaxies

September 11, 2014 Leave a comment

Scientists believe they have found a way to explain why there are not as many galaxies orbiting the Milky Way as expected. Computer simulations of the formation of our galaxy suggest that there should be many more small galaxies around the Milky Way than are observed through telescopes.

This has thrown doubt on the generally accepted theory of cold dark matter, an invisible and mysterious substance that scientists predict should allow for more galaxy formation around the Milky Way than is seen.

Now cosmologists and particle physicists at the Institute for Computational Cosmology and the Institute for Particle Physics Phenomenology, at Durham University, working with colleagues at LAPTh College & University in France, think they have found a potential solution to the problem.

Writing in the journal Monthly Notices of the Royal Astronomical Society, the scientists suggest that dark matter particles, as well as feeling the force of gravity, could have interacted with photons and neutrinos in the young Universe, causing the dark matter to scatter.

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Galaxy May Swarm with ‘Nomad Planets’

February 23, 2012 3 comments

Image Credit: Greg Stewart / SLAC National Accelerator Laboratory

Image Credit: Greg Stewart / SLAC National Accelerator Laboratory

Our galaxy may be awash in homeless planets, wandering through space instead of orbiting a star.

In fact, there may be 100,000 times more “nomad planets” in the Milky Way than stars, according to a new study by researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and the SLAC National Accelerator Laboratory.

If observations confirm the estimate, this new class of celestial objects will affect current theories of planet formation and could change our understanding of the origin and abundance of life.

“If any of these nomad planets are big enough to have a thick atmosphere, they could have trapped enough heat for bacterial life to exist,” said Louis Strigari, leader of the team that reported the result in a paper submitted to theMonthly Notices of the Royal Astronomical Society.Although nomad planets don’t bask in the warmth of a star, they may generate heat through internal radioactive decay and tectonic activity.

Full Story: http://news.stanford.edu/news/2012/february/slac-nomad-planets-022312.html

Chandra Finds Black Hole Grazing on Asteroids

February 9, 2012 Leave a comment

Image Credit: NASA/CXC/M.Weiss

Image Credit: NASA/CXC/M.Weiss

The giant black hole at the center of the Milky Way may be vaporizing and devouring asteroids, which could explain the frequent flares observed, according to astronomers using data from NASA’s Chandra X-ray Observatory.

For several years Chandra has detected X-ray flares about once a day from the supermassive black hole known as Sagittarius A*, or “Sgr A*” for short. The flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole’s regular output. The flares also have been seen in infrared data from ESO’s Very Large Telescope in Chile.

“People have had doubts about whether asteroids could form at all in the harsh environment near a supermassive black hole,” said Kastytis Zubovas of the University of Leicester in the United Kingdom, and lead author of the report appearing in the Monthly Notices of the Royal Astronomical Society. “It’s exciting because our study suggests that a huge number of them are needed to produce these flares.”

Full Story: http://chandra.si.edu/photo/2012/sgra/

Do Black Holes Help Stars Form?

February 2, 2012 1 comment

The centre of just about every galaxy is thought to host a black hole, some with masses of thousands of millions of Suns and consequently strong gravitational pulls that disrupt material around them. They had been thought to hinder the birth of stars, but now an international team of astronomers studying the nearby galaxy Centaurus A has found quite the opposite: a black hole that seems to be helping stars to form. The team, led by Dr Stanislav Shabala of the University of Tasmania, Dr Mark Crockett of the University of Oxford, and Dr Sugata Kaviraj of Imperial College, London, publish their results in the journal Monthly Notices of the Royal Astronomical Society.

Black holes at the centre of galaxies ‘switch on’ from time to time, driving material around them into outflows that can stretch for millions of light years. The flows plough through galactic gas, compressing, heating and pushing it out of the way. Much of this gas is the raw material from which stars are made, so the outflows significantly affect star formation in the galaxies that host them.

Full Story: http://www.ras.org.uk/news-and-press/219-news-2012/2070-do-black-holes-help-stars-form

From the Comfort of Home, Web Users May Have Found New Planets

September 22, 2011 Leave a comment

Since the online citizen science project Planet Hunters launched last December, 40,000 web users from around the world have been helping professional astronomers analyze the light from 150,000 stars in the hopes of discovering Earth-like planets orbiting around them.

Users analyze real scientific data collected by NASA’s Kepler mission, which has been searching for planets beyond our own solar system — called exoplanets — since its launch in March 2009.

Now astronomers at Yale University have announced the discovery of the first two potential exoplanets discovered by Planet Hunters users in a new study to be published in the Monthly Notices of the Royal Astronomical Society.

Full Story: http://opac.yale.edu/news/article.aspx?id=8898