Feeds

Astronomers eyeball smallest star yet

Just a bit bigger than Jupiter

  • alert
  • submit to reddit

The essential guide to IT transformation

Astronomers searching for extrasolar planets have discovered the smallest star spotted yet - just 16 per cent larger than Jupiter. OGLE-TR-122b was identified during analysis of data gathered during the planet-hunting OGLE project in Chile, New Scientist reports.

The OGLE survey identified almost 200 objects by watching for bodies transiting companion stars. In the case of OGLE-TR-122b, the mini-star passes before Sun-like OGLE-TR-122 once a week, dimming the light reaching Earth from the latter by 1.5 per cent. However, although observers were able to use this dimming to calculate the object's diminutive stature, it was not until it was re-examined by Frederic Pont of Switzerland's Geneva Observatory using the the Very Large Telescope in Chile that its true nature was revealed.

The New Scientist explains: "They used the telescope to study the spectrum of the larger star, which wobbles back and forth because of gravitational tugs from the smaller object. The relatively puny body weighed in at 96 times Jupiter's mass - above the threshold of 75 Jupiter-masses required for a bona fide star, which must also burn hydrogen."

Graphic of OGLE-TR-122b by European Southern Observatory

The discovery has implications for exoplanet hunters, who must when classifying objects take into account both dimming - which determines size - as well as the effects of "wobbles" on neighbouring bodies - which determine mass. Accordingly, Claudio Melo of the European Southern Observatory in Santiago, Chile, issued a note of caution for the organisers of any future space-based planet-hunting operation: "Based only on the light curves, you cannot tell what you are observing. When those space missions fly, we need to do ground-based spectroscopic measurements to confirm the nature of the transiting object."

That aside, the astronomers say this is the first time they have eyeballed a star with a radius comparable to a planet. Small it may be, but it isn't the least massive. That honour goes to a star just 93 times Jupiter's mass, announced early in 2005 by the University of Arizona. But, because that lightweight's transit of a companion object is not visible from Earth, its size is unknown. ®

Related stories

Astronomers identify mysterious 'burper'
Are pulsars gravity-wave generators?
Astronomers spot fun-sized solar system

Gartner critical capabilities for enterprise endpoint backup

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
LOHAN Kickstarter push breaks TWELVE THOUSAND POUNDS
That's right, folks, you've stumped up OVER 9000 beer tokens - and counting
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
prev story

Whitepapers

Best practices for enterprise data
Discussing how technology providers have innovated in order to solve new challenges, creating a new framework for enterprise data.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Advanced data protection for your virtualized environments
Find a natural fit for optimizing protection for the often resource-constrained data protection process found in virtual environments.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?