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On the edge of a hungry black hole

...Gas and dust equal to the mass of two Earths are being gobbled up every hour by a hungry black hole in a distant galaxy, according to a space telescope probing the Universe in X-rays that has peered closer to a black hole than ever before...

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M82's hidden supernova

...A supernova has recently exploded in the nearby galaxy M82, but you won't be able to see it with any ordinary telescope. Shrouded in obscuring gas and dust, only the radio emission of the stellar explosion was seen...

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Victoria gives Opportunity a view into Mars' history

...Opportunity's two-year stay in Mars' Victoria Crater is now bearing fruit, with the publication of the first major analysis of the erosional processes from wind and water that have sculpted the geology of the crater...

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Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

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Big planet, small star



Posted: 29 May, 2009

One of the smallest stars in the Galaxy has been found to have a planet orbiting it that is six times more massive than Jupiter. This gas giant is as far from its star as Mercury is from our Sun, but because the star is so small, it is like a scaled down version of our own Solar System, with the planet where Jupiter would be. This raises the possibility that there could be even more planets that are rocky like Earth even closer to the star.

Artwork depicting the planet around VB 10. The planet and the star should have similar diameters, but the star is more massive, about a twelfth of the mass of our Sun.

Image: NASA/JPL–Caltech.

The star in question is a red dwarf called VB 10. For a time it was one of the smallest stars known to exist. Red dwarfs are the most common type of star in the Galaxy, and are the coolest. This means that the habitable zone around stars like VB 10 – in other words, the region around the star where the temperature is just right for liquid water – will be much, much closer to the star. If an Earth-like world exists around VB 10 it will be between the star and the gas giant.

What is novel about this new discovery is the method by which the planet was found. Stuart Shaklan and Steven Pravdo from NASA’s Jet Propulsion Laboratory spent a dozen years watching for tiny wobbles in the proper motions of stars as they traverse across the night sky. This isn’t to be confused with the radial velocity method in which a planet induces a wobble in a star as it rotates on its axis.

This new astrometric method was actually first attempted 50 years ago, but accurate enough observations could not be made of the motions of stars. Now Pravda and Shaklan have shown that it is possible, using 16-megapixel CCD cameras strapped to the Hale Telescope at Mount Palomar in California.

“The method is optimal for finding solar system configurations like ours that might harbour other Earths,” says Pravda. “We found a Jupiter-like planet at around the same relative place as our Jupiter, only around a much smaller star. It’s possible this star also has inner rocky planets. And since more than seven out of ten stars are small like this one, this could mean planets are more common than we thought.”

Readers might like to view a video that shows the wobble in the proper motion of VB 10 at NASA's website here.


A comparison between our Solar System and the solar system around VB 10.

Image: NASA/JPL–Caltech.