KOI-81 is an eclipsing binary star in the constellation of Cygnus. The primary star is a late B-type or early A-type main-sequence star with a temperature of 10,000 K (9,700 °C; 17,500 °F). It lies in the field of view of the Kepler Mission and was determined to have an object in orbit around it which is smaller and hotter than the main star.[4]
 A light curve for KOI-81, adapted from van Kerkwijk et al. (2010).[1] The inset plot shows the eclipse on an expanded scale. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 19h 35m 08.577s[2] |
| Declination | 45° 01′ 06.58″[2] |
| Apparent magnitude (V) | 11.349[3] |
| Characteristics | |
| Spectral type | B9-A0V[1] |
| B−V color index | 0.204[3] |
| Details | |
| Mass | 2.71 0.19 −0.11[1] M☉ |
| Radius | 2.93 ± 0.14[1] R☉ |
| Luminosity | 77.3 ± 9.6[1] L☉ |
| Temperature | 10000[1] K |
| Other designations | |
KIC 8823868, 2MASS J19350857 4501065, GSC2.3 N2K9001230 | |
| Database references | |
| SIMBAD | data |
KOI-81b
editKOI-81b is a hot compact object orbiting KOI-81. It was discovered in 2010 by the Kepler Mission and came to attention because of its small size and high temperature of 17,000 K (16,700 °C; 30,100 °F).[4] The orbit of KOI-81b around the main star takes 23.8776 days to complete. Analysis of relativistic effects in the Kepler light curve suggests that it is a low-mass white dwarf of approximately 0.3 solar masses, produced by a previous stage of mass transfer during the object's giant phase.[1]
See also
edit- KOI-74, a similar system also discovered by the Kepler Mission.
- Kepler Object of Interest, stars observed to have transits by the Kepler Mission
References
edit- ^ a b c d e f g van Kerkwijk, Marten H.; Rappaport, Saul A.; Breton, René P.; Justham, Stephen; Podsiadlowski, Philipp; Han, Zhanwen (2010). "Observations of Doppler Boosting in Kepler Light Curves". The Astrophysical Journal. 715 (1): 51–58. arXiv:1001.4539. Bibcode:2010ApJ...715...51V. doi:10.1088/0004-637X/715/1/51. S2CID 15893663.
- ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "2MASS 19350857 4501065". 2MASS All-Sky Catalog of Point Sources. Bibcode:2003yCat.2246....0C. Retrieved 2010-06-19.
- ^ a b "GSC2.3 N2K9001230". Guide Star Catalog 2.3. Retrieved 2010-06-19.
- ^ a b Rowe, Jason F.; Borucki, William J.; Koch, David; Howell, Steve B.; Basri, Gibor; Batalha, Natalie; Brown, Timothy M.; Caldwell, Douglas; Cochran, William D.; Dunham, Edward; Dupree, Andrea K.; Fortney, Jonathan J.; Gautier, Thomas N.; Gilliland, Ronald L.; Jenkins, Jon; Latham, David W.; Lissauer, Jack J.; Marcy, Geoff; Monet, David G.; Sasselov, Dimitar; Welsh, William F. (2010). "Kepler Observations of Transiting Hot Compact Objects". The Astrophysical Journal Letters. 713 (2): L150–L154. arXiv:1001.3420. Bibcode:2010ApJ...713L.150R. doi:10.1088/2041-8205/713/2/L150. S2CID 118578253.
 | This variable star–related article is a stub. You can help Wikipedia by expanding it. |
 | This article about a white dwarf is a stub. You can help Wikipedia by expanding it. |