Page last updated at 22:32 GMT, Monday, 4 January 2010

Nasa's Kepler planet-hunter detects five worlds

By Jonathan Amos
Science correspondent, BBC News

Planet comparison (Nasa)

Nasa's Kepler Space Telescope has detected its first five exoplanets, or planets beyond our Solar System.

The observatory, which was launched last year to find other Earths, made the discoveries in its first few weeks of science operations.

Although the new worlds are all bigger than our Neptune, the US space agency says the haul shows the telescope is working well and is very sensitive.

The exoplanets have been given the names Kepler 4b, 5b, 6b, 7b and 8b.

They were announced at an American Astronomical Society meeting in Washington DC.

The planets range in size from an object that has a radius four times that of Earth, to worlds much bigger than even our Jupiter.

And they all circle very close to their parent stars, following orbits that range from about 3.2 to 4.9 days.

This proximity and the fact that the host stars are themselves much hotter than our Sun means Kepler's new exoplanets experience an intense roasting.

Intriguing density

Estimated temperatures go from about 1,200C to 1,650C (2,200F to 3,000F).

"The planets we found are all hotter than molten lava; they all simply glow with their temperatures," said Bill Borucki, Kepler's lead scientist from Nasa's Ames Research Center in Moffett Field, California.

THE KEPLER SPACE TELESCOPE
Infographic (BBC)
Will study more than 100,000 suns
Continuously for 4 to 6+ years
Tuned to see Earth-size planets
Will target the habitable zone
Will also see Mars to Jupiter sizes

"In fact the upper two are hotter than molten iron and looking at them might be like looking at a blast furnace. They are very bright in their own right and certainly no place to look for life."

Kepler 7b will intrigue many scientists. It is one of the lowest-density exoplanets (about 0.17 grams per cubic centimetre) yet discovered.

"The average density of this planet with its core is about the same as Styrofoam," explained Dr Borucki. "So it's an amazingly light planet, something I'm sure theoreticians will be delighted to look at in terms of trying to understand [its] structure."

Kepler blasted into space atop a Delta II rocket from Cape Canaveral Air Force Station on 6 March, 2009.

It is equipped with the largest camera ever launched into space. The telescope's mission is to continuously and simultaneously observe more than 100,000 stars.

It senses the presence of planets by looking for a tiny "shadowing" effect when one of them passes in front of its parent star.

'Water worlds'

Kepler's detectors, built by UK firm e2v, have extraordinary sensitivity.

Nasa says that if the observatory were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front of it.

Artist's impression of a Jupiter-size exoplanet - NASA/JPL-Caltech/T. Pyle (SSC)
Artist's impression: Four of the five are bigger than a Jupiter

The space agency hopes this sensitivity will lead it to planets that are not only Earth-size but which orbit their stars at distances more favourable to life, where liquid water might potentially reside on their surfaces.

The mission's scientists told the AAS meeting that Kepler had measured hundreds of possible planet signatures but that these needed further investigation to establish their true nature.

To confirm the existence of the most ideal Earth-like planets would take a few years, they warned.

In the meantime, all detections will help scientists improve their statistics on the distributions of planet size and orbital period.

The follow-up observations needed to confirm the new exoplanets' existence used a suite of ground-based facilities including the Keck I telescope in Hawaii.

Jonathan.Amos-INTERNET@bbc.co.uk



Print Sponsor


SEE ALSO
Cool find in hunt for exoplanets
03 Dec 09 |  Science & Environment
Lithium clue for planet-hunters
11 Nov 09 |  Science & Environment
Scientists announce planet bounty
19 Oct 09 |  Science & Environment
Distant world 'has rocky surface'
16 Sep 09 |  Science & Environment
'Lightest' exoplanet discovered
21 Apr 09 |  Science & Environment
Nasa launches Earth hunter probe
07 Mar 09 |  Science & Environment
UK 'eyes' to hunt for other Earths
17 Feb 09 |  Science & Environment

RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites

FROM OTHER NEWS SITES
San Francisco Chronicle NASA telescope detects 5 sizzling exoplanets - 7 hrs ago
Telegraph Nasa telescope detects five planets outside the solar system - 23 hrs ago
Xinhua News Agency NASA's Kepler space telescope discovers five exoplanets - 26 hrs ago
Christian Science Monitor NASA's Kepler finds its first five planets - an odd assortment - 29 hrs ago
National Geographic Five New Planets Found; Hotter Than Molten Lava - 32 hrs ago



FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC navigation

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific