Institute of Astronomy

Feed aggregator

Sibling Stars

Astronomy News - 20 August 2015 - 9:36am
Open star clusters like the one seen here are not just perfect subjects for pretty pictures. Most stars form within clusters and these clusters can be used by astronomers as laboratories to study how stars evolve and die. The cluster captured here by the Wide Field Imager (WFI) at ESO’s La Silla Observatory is known as IC 4651, and the stars born within it now display a wide variety of characteristics.

Astrophysics: Mystery survivor of a supermassive black hole

Astronomy News - 20 August 2015 - 9:34am

Astrophysics: Mystery survivor of a supermassive black hole

Nature 524, 7565 (2015). doi:10.1038/524301a

Authors: John Bally

The G2 cloud in our Galaxy's core has survived an encounter with the central black hole and failed to trigger a major flare-up in the black hole's activity. A promising theory endeavours to explain the cloud's nature.

Growing the gas-giant planets by the gradual accumulation of pebbles

Astronomy News - 20 August 2015 - 9:34am

Growing the gas-giant planets by the gradual accumulation of pebbles

Nature 524, 7565 (2015). doi:10.1038/nature14675

Authors: Harold F. Levison, Katherine A. Kretke & Martin J. Duncan

It is widely held that the first step in forming gas-giant planets, such as Jupiter and Saturn, was the production of solid ‘cores’ each with a mass roughly ten times that of the Earth. Getting the cores to form before the solar nebula dissipates (in about one to ten million years; ref. 3) has been a major challenge for planet formation models. Recently models have emerged in which ‘pebbles’ (centimetre-to-metre-sized objects) are first concentrated by aerodynamic drag and then gravitationally collapse to form objects 100 to 1,000 kilometres in size. These ‘planetesimals’ can then efficiently accrete left-over pebbles and directly form the cores of giant planets. This model is known as ‘pebble accretion’; theoretically, it can produce cores of ten Earth masses in only a few thousand years. Unfortunately, full simulations of this process show that, rather than creating a few such cores, it produces a population of hundreds of Earth-mass objects that are inconsistent with the structure of the Solar System. Here we report that this difficulty can be overcome if pebbles form slowly enough to allow the planetesimals to gravitationally interact with one another. In this situation, the largest planetesimals have time to scatter their smaller siblings out of the disk of pebbles, thereby stifling their growth. Our models show that, for a large and physically reasonable region of parameter space, this typically leads to the formation of one to four gas giants between 5 and 15 astronomical units from the Sun, in agreement with the observed structure of the Solar System.

Astronomy: Direct look at a small exoplanet

Astronomy News - 20 August 2015 - 9:34am

Astronomy: Direct look at a small exoplanet

Nature 524, 7565 (2015). doi:10.1038/524268c

Astronomers have snapped a picture of a planet like those in the Solar System but orbiting another star — the lowest-mass exoplanet ever directly imaged.Bruce Macintosh of Stanford University in California and his team used the Gemini Planet Imager at the Gemini South Telescope

Rosetta sees sparks as comet 67P reaches closest approach to sun

Astronomy News - 20 August 2015 - 9:29am
The European Space Agency's comet team are celebrating perihelion, the day when comet 67P swings around the sun, taking Rosetta for a ride

Comet impacts cook up 'soup of life'

Astronomy News - 20 August 2015 - 9:27am

New lab results show how collisions between comets and planets can make the molecules that are the essential building blocks of life.

Send Your Name to Mars on NASA's Next Red Planet Mission

Astronomy News - 19 August 2015 - 9:05am
Mars enthusiasts around the world can participate in NASA’s journey to Mars by adding their names to a silicon microchip headed to the Red Planet aboard NASA's InSight Mars lander, scheduled to launch next year.

Moon’s gravity could govern plant movement like the tides

Astronomy News - 18 August 2015 - 9:28am

Historical data on how plants move over the course of the day seems to show that they line up with the position of the moon

Small stars may keep planets in line with magnetic harnesses

Astronomy News - 18 August 2015 - 9:27am

Some planets orbit their stars right around the star's equator, while others go at wonky angles – and it's all down to the star's size

Young 'alien Jupiter' discovered

Astronomy News - 17 August 2015 - 9:22am

A planet 100 light-years away resembles a young version of Jupiter, astronomers say.

VIDEO: Timelapse shows Northern Lights from space

Astronomy News - 17 August 2015 - 9:22am

Nasa astronaut Scott Kelly captures timelapse footage of Aurora Borealis, also known as the Northern Lights, from the International Space Station.

What makes a planet habitable?

Astronomy News - 17 August 2015 - 9:21am

Working out what is necessary for life

Rosetta's big day in the Sun

Astronomy News - 14 August 2015 - 9:34am

ESA's Rosetta today witnessed Comet 67P/Churyumov-Gerasimenko making its closest approach to the Sun. The exact moment of perihelion occurred at 02:03 GMT this morning when the comet came within 186 million km of the Sun.

NASA's Hubble Finds Supernovae in 'Wrong Place at Wrong Time'

Astronomy News - 14 August 2015 - 9:34am

Get larger image formats

What happens when you find something in the wrong place at the wrong time? That's a question astronomers have been trying to answer after finding several exploding stars outside the cozy confines of galaxies, where most stars reside. These wayward supernovae also have puzzled astronomers because they exploded billions of years before their predicted detonations. Astronomers using archived observations from several telescopes, including the Hubble Space Telescope, have developed a theory for where these doomed stars come from and how they arrived at their current homes.

Newly Discovered World Is Most Like Jupiter

Astronomy News - 14 August 2015 - 9:33am

Get larger image formats

A team of astronomers, including half a dozen from the Space Telescope Science Institute (STScI) in Baltimore, Maryland, have used the Gemini Observatory's new Gemini Planet Imager to find the most solar system-like planet ever directly imaged around another star. The planet, known as 51 Eridani b, is about two times the mass of Jupiter and orbits its host star at about 13 times the Earth-sun distance (equivalent to being between Saturn and Uranus in our solar system). The planet is located about 100 light-years away from Earth. The Gemini data provide scientists with the strongest-ever spectroscopic detection of methane in the atmosphere of an extrasolar planet, adding to its similarities to giant planets in our solar system. "This planet looks like a younger, slightly bigger version of Jupiter," said Dr. Laurent Pueyo of STScI, one of the astronomers who carefully measured the planet's light against the background glare of starlight. "That we can see so clearly the presence of methane for a planet a million times fainter than its star, even through the atmosphere, bodes very well for the future characterization of even fainter planets from space using the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope."

VIDEO: Perseid shower in 45 seconds

Astronomy News - 14 August 2015 - 9:14am

Stargazers captured the dazzling display of the annual Perseid meteor shower as it reached its peak on Wednesday night. BBC News viewers sent in their photos.

Astronomy: Stars align to show new planet

Astronomy News - 13 August 2015 - 12:03pm

Astronomy: Stars align to show new planet

Nature 524, 7564 (2015). doi:10.1038/524138d

Two teams using different telescopes have confirmed that a planet with a mass similar to that of Uranus is orbiting a distant star.Most known exoplanets orbit close to their stars, but in 2005 researchers using an effect called microlensing spotted a planet with a

Sniff out alien life with giant library of weird chemicals

Astronomy News - 13 August 2015 - 12:01pm

The search for vital signs of life in the atmospheres of other planets has taken a new turn with a vast library of biosignatures that could help us detect ET

VIDEO: Why the Perseids happen every year

Astronomy News - 13 August 2015 - 9:12am

The BBC's Pallab Ghosh explains why the Perseid meteor shower happens every year.

VIDEO: Perseid meteor shower photos in 60 secs

Astronomy News - 13 August 2015 - 9:12am

A look at some of your photos of the Perseid meteor shower in 60 seconds.