The
search for little green men continues...
Micheal Ashley
We
have a research team at the University of New South Wales
that is using the Automated
Patrol Telescope at Siding Spring Observatory
to search for extra-solar planets, i.e.,
planets that orbit around stars other than the Sun. The search
monitors tens of thousands of stars for small brightness variations
that could be due to planets passing between the stars and
the earth.
All the observations for the search are conducted automatically
by the telescope. The staff and students in our team take
turns monitoring the progress of the observations using
the internet from Sydney.
The highlight of the day was a meeting of our research team
to discuss a paper we are writing on a discovery that came
out of this search: not an extra-solar planet, unfortunately,
but a very interesting double star system.
We have found two stars orbiting each other every 2.12 days.
Each star is half the mass of our Sun, and the stars are only
0.033 Astronomical
Units apart.
For a simulation of what the double star system would look
like rising above the Malabar Headland on the coast near Sydney,
Australia, see
http://www.phys.unsw.edu.au/~mcba/k7vstars.jpg
The significance of this discovery is that of all the 200
billion or so stars in our Milky Way Galaxy, this is only
one of six low-mass double stars known that allow an accurate
determination of the stars' masses and radii. This is crucial
information for verifying models of stellar evolution.
Intriguingly, the orbit of our double star is significantly
noncircular, which could point to the existence of a third
body, perhaps a large planet, orbiting both
stars. Further observations will be needed to untangle
this mystery.
I decided at the age of 9 to be a scientist when I grew up,
and astronomy became my passion when I built a 20-cm Newtonian
telescope while at High School.
Now on the Faculty at the University of New South Wales, I
am still interested in building telescopes,
this time on the high plateau in the centre of Antarctica,
which has the best conditions on earth for ground-based observations.
But that is another story...
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