Planetary System
On November 14, 1999, the discovery of a planet HD 177830 b was announced by the California and Carnegie Planet Search team using the very successful radial velocity method along with two other planets. This planet is nearly 50% more massive than Jupiter and takes 407 days to orbit the star in an extremely circular orbit. In 2000 a group of scientists proposed, based on preliminary Hipparcos astrometrical satellite data, that the orbital inclination of HD 177830 b is as little as 1.3°. If that was the case, the planet would have a mass of 67 times that of Jupiter making it a brown dwarf instead of a planet. However, it is very unlikely that the planet would have such orbit. Furthermore, brown dwarfs with short orbits around solar-mass stars are exceedingly rare (the so-called "brown dwarf desert") making the claim even more unlikely.
On November 17, 2010, the discovery of a second planet HD 177830 c was announced along with four other planets. The planet has 50% the mass of Saturn and takes 111 days to orbit the star in a very eccentric orbit. This planet is in a near 4:1 resonance with the outer planet.
| Companion |
Mass | Semimajor axis |
Orbital period |
Eccentricity | Radius |
|---|---|---|---|---|---|
| c | ≥0.15 ± 0.03 MJ | 0.5137 ± 0.0006 | 110.9 ± 0.3 | 0.3495 ± 0.0002 | — |
| b | ≥1.49 ± 0.03 MJ | 1.2218 ± 0.0008 | 406.6 ± 0.4 | 0.009 ± 0.004 | — |
Read more about this topic: HD 177830
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