Star 'gnome' is nuclear surprise

Hmm, I wonder if they spotted monoliths in the area and/or Apes on a
nearby moon :-)

--
Keith


http://news.bbc.co.uk/1/hi/sci/tech/4319061.stm

Star 'gnome' is nuclear surprise

A comparison between our Sun, Jupiter and the stellar "gnome"
A shining star has been located that is not much bigger than Jupiter,
the biggest planet in our Solar System.
The discovery is fascinating, say scientists, because it shows how
small an object can be and still trigger the nuclear reactions for
sunshine.

The existence of the star, known as OGLE-TR-122B, was confirmed by the
Very Large Telescope (VLT) in Chile.

Sited in the Carina constellation, the stellar "gnome" was seen to
pass in front of a much bigger companion star.

As it did so, it dimmed the companion's light received at the VLT, a
facility run by the European Southern Observatory organisation (ESO).

In a volume

It is not known precisely how big an object needs to be to shine. At
some point a gas body will become so massive that the gravitational
forces pulling material into its core will initiate fusion reactions -
just like those at the core of our Sun that give us light.

What is interesting is that although OGLE-TR-122B is a mere 16% larger
than Jupiter, it is actually 96 times more massive.

"Imagine that you add 95 times its own mass to Jupiter and
nevertheless end up with a star that is only slightly larger,"
suggests Claudio Melo, from ESO and member of the team of astronomers
who made the study.

"The object just shrinks to make room for the additional matter,
becoming more and more dense."

Indeed, the density of OGLE-TR-122B is more than 50 times greater than
that of our own Sun.

Setting limits

The stellar gnome shines, but not very brightly - especially when
compared with the energy released by its large companion star.

"This result shows the existence of stars that look strikingly like
planets, even from close by," said Frederic Pont, of the Geneva
Observatory, Switzerland.

"Isn't it strange to imagine that even if we were to receive images
from a future space probe approaching such an object at close range,
it wouldn't be easy to discern whether it is a star or a planet?"

What is remarkable, however, is that OGLE-TR-122B is actually smaller
than some of the planets discovered recently outside our Solar System.

Details of the study on OGLE-TR-122B will appear in a forthcoming
edition of the journal Astronomy & Astrophysics.



_____

"Cosmic upheaval is not so moving as a little child pondering the death
of a sparrow in the corner of a barn." -Anouk Aimee, French Actor
_____

"Death is better, a milder fate than tyranny", Aeschylus (525BC-456BC),
Agamemnon
_____

"I wear no Burka." - Mother Nature

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