BBC News/ Astronomers using a
telescope in Chile have discovered 50 previously unknown exoplanets.
The bumper haul of
new worlds includes 16 "super-Earths" - planets with a greater mass
than our own, but below those of gas giants such as Jupiter.
One of these
super-Earths orbits inside the habitable zone - the region around a star where
conditions could be hospitable to life.
The planets were
identified using the Harps instrument in La Silla in Chile.
The new findings are
being presented at a meeting called Extreme Solar Systems in Wyoming, US, and
will appear in the journal Astronomy and Astrophysics.
Lead author Dr
Michel Mayor, from the University of Geneva in Switzerland, said the haul
included "an exceptionally rich population of super-Earths and
Neptune-type planets hosted by stars very similar to our Sun".
He added: "The
new results show that the pace of discovery is accelerating."
Life markers
Of the new finds, a
total of five planets have masses that are less than five times that of Earth.
"These planets
will be among the best targets for future space telescopes to look for signs of
life in the planet's atmosphere by looking for chemical signatures such as
evidence of oxygen," said Francesco Pepe, from the Geneva Observatory, who
contributed to the research.
One of the worlds,
called HD 85512 b, is estimated to be only 3.6 times the mass of the Earth.
It is located at the
edge of the habitable zone - the narrow strip around a star where liquid water
can be present on the surface of a planet. Liquid water is considered essential
for the existence of life.
Observations with
Harps have also allowed astronomers to come up with an improved estimate of the
likelihood that a star such as the Sun will host low-mass planets such as the
Earth (as opposed to giants such as Jupiter).
They found that
about 40% of such stars have at least one planet less massive than Saturn.
Harps (High Accuracy
Radial Velocity Planet Searcher) is a precision instrument known as a
spectrograph that is installed on the 3.6m telescope at Chile's La Silla
Observatory.
The instrument
searches for planets using the radial velocity method. This looks for spectral
signs that a star is wobbling due to gravitational tugs from an orbiting
planet.
The star HD 85512
lies some 35 light-years away and hosts a potentially habitable planet
0 comments:
Post a Comment