HD 159868

HD 159868

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Scorpius
Right ascension	17^h 38^m 59.526^s
Declination	−43° 08′ 43.85″
Apparent magnitude (V)	+7.24
Absolute magnitude (V)	+3.63[note 1]
Distance	171.93 ly (52.71 pc)
Spectral type	G5V
Other designations
CD-43º11901, GC 23898, GCRV 67207, GJ 4014, HIP 86375, SAO 228234
Database references
SIMBAD	data

HD 159868 is a yellow dwarf star approximately 172 light-years away in the constellation of Scorpius. The star is thought to be 3.05 times more luminous than the Sun, yet the metallicity is identical to the Sun.

Planetary system

• In 2007, a planet of the star was announced by astronomer Simon J. O'Toole.^[1] The planet (designated HD 159868 b) is likely to be a gas giant. The orbit is extremely eccentric at the average distance of 2 astronomical units (AU), ranging as close as 0.62 AU to as far as 3.38 AU. During its orbital period, the planet spends most of its time in the habitable zone of its star.
• In 2012, a second planet of the star was announced by astronomer Robert A. Wittenmyer.^[2]

The HD 159868 planetary system^[1][2]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
c	>0.73 ± 0.05 MJ	1 ± 0.01	352.3 ± 1.3	0.15 ± 0.05	—	—
b	>2.1 ± 0.1 MJ	2.25 ± 0.03	1178.4 ± 8.8	0.01 ± 0.03	—	—

See also

• HD 219828
• HD 28185
• List of extrasolar planets

References

1. O'Toole, Simon J.; et al. (2007). "New Planets around Three G Dwarfs". The Astrophysical Journal 660 (2): 1636–1641. arXiv:astro-ph/0702213. Bibcode:2007ApJ...660.1636O. doi:10.1086/513563.
2. Wittenmyer; et al. (2012). "The Anglo-Australian Planet Search. XXII. Two New Multi-planet Systems". The Astrophysical Journal 753 (2). arXiv:1205.2765. Bibcode:2012ApJ...753..169W. doi:10.1088/0004-637X/753/2/169.

Notes

1. The calculation for absolute magnitude applied here is $\begin{smallmatrix} M = m - 5 ((\log_{10}{D_L}) - 1)\!\,\end{smallmatrix}$, where $\begin{smallmatrix}m\!\,\end{smallmatrix}$ is the apparent magnitude and $\begin{smallmatrix}D_L\!\, \end{smallmatrix}$ is the luminosity distance in parsecs.

External links

• "HD 159868". Exoplanets. Retrieved 2008-07-19.
• "Notes for star HD 159868". The Extrasolar Planets Encyclopedia. Retrieved 2008-07-19.

Coordinates: 17^h 38^m 59.526^s, −43° 08′ 43.85″