HD 240210 is a star in the northern constellation of Cassiopeia. It has an orange hue but is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.33.[2] Parallax measurements provide an estimate of its distance from the Sun as approximately 1,230 light years. It is drifting further away with a radial velocity of +8.6 km/s.[1]
This is an aging giant star with a class of K3,[2] which has exhausted the supply of hydrogen at its core and expanded to 25[1] times the radius of the Sun. It is around three[3] billion years old with 1.3[2] times the Sun's mass. The star is radiating 152 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,019 K.[1] It is spinning slowly, with each rotation taking at least 1.8 years.[2]
On June 10, 2009 a planet orbiting the star was discovered by Niedzielski et al. This exoplanet is a 6.9 or greater Jupiter mass planet. Evidence for additional planetary companions has been found.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 6.90 MJ | 1.33 | 501.75±2.33 | 0.15±0.02 | — | — |
See also
References
- ^ a b c d e f g h i j k l Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f g h i j k l m Niedzielski, A.; et al. (2009). "Substellar-mass Companions to the K-dwarf BD+14 4559 and the K-giants HD 240210 and BD+20 2457". The Astrophysical Journal. 707 (1): 768–777. arXiv:0906.1804. Bibcode:2009ApJ...707..768N. doi:10.1088/0004-637X/707/1/768. S2CID 16877069.
- ^ a b Adamczyk, M.; et al. (2016). "Masses and luminosities for 342 stars from the PennState-Toruń Centre for Astronomy Planet Search". Astronomy and Astrophysics. 587: A119. arXiv:1510.07495. Bibcode:2016A&A...587A.119A. doi:10.1051/0004-6361/201526628. S2CID 119299522.
- ^ "HD 240210". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-17.
- ^ Adamów, M.; et al. (July 2011). Martin, E.L.; Ge, J.; Lin, W. (eds.). A search for planets around intermediate Mass Stars with the Hobby-Eberly Telescope. Research, Science and Technology of Brown Dwarfs and Exoplanets: Proceedings of an International Conference held in Shangai on Occasion of a Total Eclipse of the Sun, Shangai, China. EPJ Web of Conferences. Vol. 16. Bibcode:2011EPJWC..1602005A. doi:10.1051/epjconf/20111602005. 02005.
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