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When, 25 years ago, the dusty protoplanetary disk around Beta Pictoris was imaged for the first time, it immediately suggested that planet formation was a common phenomenon. Many years later, in November 2003, a planet candidate was identified in the disk, and was later confirmed in 2009 with a series of infrared images. These images showed, that since 2003, the planet had in fact completed exactly half an orbit around the star.
In March of last year the planet was once again targeted for study, this time by M. Bonnefoy, A.M. Lagrange and other researchers with the adaptive optics instrument NACO at the VLT in Cerro Paranal, Chile. The results have now been published in Astronomy & Astrophysics, and, in combination with the previous data, provide a very complete picture of the Beta Pictoris system.
Beta Pictoris is 63.4 light years away with a mass 1.75 times that of the Sun, however, it is much younger than the Sun, being only 12 million years old (compared to 5 billion for the Sun). This difference probably explains the presence of a protoplanetary disk, within which other planets may well be in the process of forming, waiting for us to be able to detect them.
The recent infrared observation of Beta Pictoris in the Ks
band (2.18 micron) by Bonnefoy and Lagrange has made it possible to
measure the colour of the planet, allowing a good, direct measure of
its surface temperature, 1700+/-300 K. The mass estimated is 7-11
Jovian masses, consistent with previous values derived from models.
Beta Pictoris b is actually the closest planet to its parent star to
have been imaged directly, having an orbital radius of between 8 and
15 astronomical units. This system provides an excellent opportunity
to study the interaction between a planet and the protoplanetary
disk.
Further observations are planned with NACO and with the future
Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE)
instrument, that should allow measurements of the planet's
atmosphere.
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