HD 20782

HD 20782
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Fornax
Right ascension 03h 20m 03.5776s
Declination –28° 51′ 14.656″
Apparent magnitude (V) 7.38
Absolute magnitude (V)4.60
Distance117 ly
(36 pc)
Spectral typeG3V
Other designations
CD-29°1231, HIP 15527, LTT 1582, SAO 168469
Database references
SIMBADdata

HD 20782 is a 7th magnitude G-type main sequence star about 117 light-years away in the constellation of Fornax. HD 20782 is a part of a wide binary system with HD 20781, both stars host a planetary system. This is the first known case of planetary systems around both stars, the primary and secondary in the binary system. The companion is HD 20781. It has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782.[1] It is estimated to be 7.1 (± 4) billion years old, with a mass close to that of our Sun.

An extremely eccentric extrasolar planet was announced around the primary star HD 20782 in 2006.[2][3] In 2009 its orbit was narrowed down, and found to have the highest eccentricity of all known exoplanets, which distinction has stood as of 2012.

And in 2011 two also-eccentric (but less so) Neptune-mass planets were announced around the secondary star HD 20781.[4][5]

Planetary systems

HD 20782

The HD 20782 planetary system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 1.80 ± 0.23 MJ 1.36 ± 0.12 585.86 ± 0.03 0.97 ± 0.01[6] — —

HD 20781

The HD 20781 planetary system[7]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 12.04 ± 1.11 M⊕ 0.169 ± 0.0028 29.15 ± 0.0201 0.11 ± 0.06 — —
c 15.76 ± 1,20 M⊕ 0.3456 ± 0.0047 85.131 ± 0.1161 0.28 ± 0.09 — —

See also

References

  1. ↑ http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...462..345DFUL
  2. 1 2 Jones; et al. (2006). "High-eccentricity planets from the Anglo-Australian Planet Search" (abstract). Monthly Notices of the Royal Astronomical Society 369: 249–256. arXiv:astro-ph/0603335. Bibcode:2006MNRAS.369..249J. doi:10.1111/j.1365-2966.2006.10298.x. (web preprint)
  3. ↑ Schneider, J. "Notes for HD 20782 |cite web". The Extrasolar Planets Encyclopaedia.
  4. ↑ Schneider, J. "Notes for star HD 20781 |cite web". The Extrasolar Planets Encyclopaedia. Retrieved 2011-09-12.
  5. ↑ Mayor, M. Marmier,M. Lovis,C. Udry,S. Ségransan,D. Pepe,F. Benz,W. Bertaux,J.-L. Bouchy,F. Dumusque, G. Curto,Lo Mordasini,C. Queloz,D. Santos,N. C.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 [astro-ph].
  6. ↑ S. J. O'Toole, C. G. Tinney, H. R. A. Jones, R. P. Butler, G. W. Marcy, B. Carter, J. Bailey (2009). "Selection Functions in Doppler Planet Searches". MNRAS. 392, 641. arXiv:0810.1589. Bibcode:2009MNRAS.392..641O. doi:10.1111/j.1365-2966.2008.14051.x.
  7. ↑ Schneider, J. "Notes for star HD 20781". The Extrasolar Planets Encyclopaedia. Retrieved 2011-09-12.

External links

Coordinates: 03h 20m 03.5776s, −28° 51′ 14.656″


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