Transit Search Finds Super-Neptune

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This artist's conception reveals the newly discovered Super-Neptune planet orbiting a star 120 light years away from Earth. Normally blue in color, its red hue is caused by the illumination from the nearby Red Dwarf star. Credit: David A. Aguilar (CfA)

(PhysOrg.com) -- Astronomers at the Harvard-Smithsonian Center for Astrophysics have discovered a planet somewhat larger and more massive than Neptune orbiting a star 120 light-years from Earth. While Neptune has a diameter 3.8 times that of Earth and a mass 17 times Earth's, the new world (named HAT-P-11b) is 4.7 times the size of Earth and has 25 Earth masses.

HAT-P-11b was discovered because it passes directly in front of (transits) its parent star, thereby blocking about 0.4 percent of the star's light. This periodic dimming was detected by a network of small, automated telescopes known as "HATNet," which is operated by the Center in Arizona and Hawaii. HAT-P-11b is the 11th extrasolar planet found by HATNet, and the smallest yet discovered by any of the several transit search projects underway around the world.

Transit detections are particularly useful because the amount of dimming tells the astronomers how big the planet must be. By combining transit data with measurements of the star's "wobble" (radial velocity) made by large telescopes like Keck, astronomers can determine the mass of the planet.

A number of Neptune-like planets have been found recently by radial velocity searches, but HAT-P-11b is only the second Neptune-like planet found to transit its star, thus permitting the precise determination of its mass and radius.

The newfound world orbits very close to its star, revolving once every 4.88 days. As a result, it is baked to a temperature of around 1100 degrees F. The star itself is about three-fourths the size of our Sun and somewhat cooler.

There are signs of a second planet in the HAT-P-11 system, but more radial velocity data are needed to confirm that and determine its properties.

Another team has located one other transiting super-Neptune, known as GJ436b, around a different star. It was discovered by a radial velocity search and later found to have transits.

"Having two such objects to compare helps astronomers to test theories of planetary structure and formation," said Harvard astronomer Gaspar Bakos, who led the discovery team.

HAT-P-11 is in the constellation Cygnus, which puts in it the field of view of NASA's upcoming Kepler spacecraft. Kepler will search for extrasolar planets using the same transit technique pioneered by ground-based telescopes. This mission potentially could detect the first Earth-like world orbiting a distant star. "In addition, however, we expect Kepler to measure the detailed properties of HAT-P-11 with the extraordinary precision possible only from space," said Robert Noyes, another member of the discovery team.

Provided by Harvard-Smithsonian Center for Astrophysics

   

• theophys - Jan 20, 2009
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  We've got to find better names for planets. I understand the scientific pruposes behind the bland names, but I think the laymen should be given a name that's easier to remember like Gassex or Fatngassy.
  Also, why did they relate this planet to Neptune? Other than being a gas planet, it really didn't have anything to do with Neptune.
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• paulthebassguy - Jan 20, 2009
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  I agree, we need more awesome names. I think that it was related to Neptune because it is the planet in our solar system which is most similar to this in terms of size & mass.
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• Going - Jan 20, 2009
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  I doubt whether exo planets deserve names . Like most stars they will exist with coded numbers until something catches human interest and makes them worth naming. Its pointless and impossible to name everyone.
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• Mercury_01 - Jan 20, 2009
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  I vote we name them all Steven seagull.
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• Modernmystic - Jan 21, 2009
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  I doubt whether exo planets deserve names . Like most stars they will exist with coded numbers until something catches human interest and makes them worth naming. Its pointless and impossible to name everyone.

  
  
  Usually I'd agree, but it really doesn't take a lot of time or imagination to name 335 objects...especially if your job is finding them. I think it boils down to lack of imagination or some kind of dogma that infests the scientific community on he subject.
  
  There is simply NO reason not to name more, if not all of these bodies...especially the most grevious examples like MOA-2007-BLG-192-L...I mean come on seriously. If some dingbat can string together that many numbers and letters they can certianly have the time to call it something else...hell there are tons of random name generators out there on line if they're ESPECIALLY unimaginative or lazy.
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• theophys - Jan 21, 2009
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  I think the scientific names should be kept. It's a good way of universally cataloging celestial objects. But it took a year for me to figure out what they were talking about when they said M10 or O67-B. Something as simple as Black Hole 467 or Bright-thing-with-no-name 8 would work better for press releases.
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• Honor - Jan 21, 2009
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  i agree, what's wrong with giving them names? im sure you can keep the scientific designation, but just add the aka, i mean we use to name nebula's, so that's the big deal.
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• Thecis - Jan 26, 2009
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  In chemistry for almost every compound there is a scientific name and a trivial name. Most of the people know the ordinary names and when you wonder why it has certain properties, people don't know it because they don't know its structure. The same applies for the pharmaceutical world.
  
  The same could be used for the names of celestial objects. The scientific name can be used by astronomers (because it will probably give some details about what it is all about) and the "normal" names for the public.
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