Youngest forming planet discovered

Youngest forming planet discovered
Astronomers have found an embryonic planet.
Provided by the Royal Astronomical Society

Using radio observatories in the UK and US and computer simulations, a team of astronomers has identified the youngest forming planet yet seen. Team leader Jane Greaves of the University of St. Andrews will discuss this new protoplanet in her talk at the RAS National Astronomy Meeting in Belfast on Wednesday April 2.Taking advantage of a rare opportunity to use the Very Large Array (VLA) of radio telescopes in the U.S. with the special addition of an extra telescope 50 kilometers away, the team studied the disk of gas and rocky particles around the star HL Tau. This star is thought to be less than 100,000 years old (by comparison the Sun is 4,600 million years old) and lies in the direction of the constellation of Taurus at a distance of 520 light-years. The disk around HL Tau is unusually massive and bright, which makes it an excellent place to search for signs of forming planets.The VLA gives very sharp images of HL Tau and its surroundings. The team studied the system using radio emission at a wavelength of 1.3 cm, specifically chosen to search for the emission from super-large rocky particles about the size of pebbles. The presence of these pebbles is a clue that rocky material is beginning to clump together to form planets.In the UK, scientists used the MERLIN array of radio telescopes centered on Jodrell Bank in Cheshire, to study the same system at longer wavelengths. This allowed the astronomers to confirm that the emission is from rocks and not from other sources such as hot gas. Jodrell Bank scientists Anita Richards and Tom Muxlow analyzed the data.

On the top is an image from the computer simulation of HL Tau and its surrounding disk. In the model the dense clump (seen here at top right) forms with a mass of about 8 times that of Jupiter at a distance from the star about 75 times that from the Earth to the Sun. Ken Rice/Royal Observatory Edinburgh. The next image is a radio emission map.

The big surprise was that, as well as detecting super-large dust in the disk around HL Tau, an extra bright clump was seen in the image. It confirms tentative nebulosity reported a few years earlier at around the same position, by a team lead by Jack Welch of the Berkeley-Illinois-Maryland Array. The new image shows the same system in much greater detail.

...... and much more in Astronomy magazine

Acknowledgements: Newsletter to me from Astronomy.com

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Jupiter Auroras "Northern Lights on Steroids"

March 30, 2007—No, Jupiter hasn't acquired a new toupee and goatee to impress Venus.

Those dashing purple puffs are x-ray images of the gas giant's high-voltage auroras—"northern lights on steroids," said planetary scientist Randy Gladstone of this image released yesterday by NASA.

The colorized picture is something of a collage. Several x-ray images taken by NASA's Chandra X-Ray Observatory have been combined and superimposed on the latest Hubble Space Telescope image of Jupiter.

"Jupiter has auroras bigger than our entire planet," said Gladstone, of the independent, nonprofit Southwest Research Institute in Texas, in a statement.

Gladstone hopes these latest observations will help him crack some Jovian mysteries. For starter, what causes these "hyper-auroras"?

The solar system's biggest planet and its magnetic field rotate extremely quickly—every ten hours—generating ten million volts around its poles. Toss in charged particles from the volcanic moon Io and you've got a crackling, nonstop sky show.

But how do the volcanic particles get from a relatively small moon to Jupiter's planetary poles? That, Gladstone says, remains one of the planet's unsolved puzzles.

courtesy: article by Ted Chamberlain in National geographic news

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