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HR 8799

This relatively young white star has one of the most massive dust disks of all stars within a range of 300 light-years. And it has three exoplanets, which in November 2008 all have been photographed in one image (in near infrared), the first image of multiple exoplanets. Yet c and d could be small brown dwarfs as well.

The planets:
HR 8799 d: 10 times mass of Jupiter, 1,2 times its diameter, 24 AU distance, 100 years orbit period.
HR 8799 c: 10 times mass of Jupiter, 1,2 times its diameter, 38 AU distance, 189 years orbit period.
HR 8799 b: 7 times mass of Jupiter, 1,1 times its diameter, 68 AU distance, 465 years orbit period.

Constellation: Pegasus
Age: 60 million years
Distance: 128 light-years
Spectral class: A5
Visual magnitude: 5.69
Luminosity: 5 * Sun
Mass: 1.5 * Sun

Back: List of Exoplanets


    HR 8799
The arrows show the paths of the planets within four years.
Photo: Keck Observatory / Christian Marois and Bruce Macintosh

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