Epoch J2000 Equinox J2000
|Right ascension||19h 53m 17.811s|
|Declination||+42° 23′ 18.52″|
|Apparent magnitude (V)||10.715|
|B−V color index||0.154|
|Luminosity||25.6 ± 2.4 L☉|
|Temperature||9400 ± 150 K|
KIC 6889235, 2MASS J19531781+4223185, GSC2.3 N2J3000844
KOI-74 (KIC 6889235) is an eclipsing binary star in the constellation of Cygnus. The primary star is an A-type main-sequence star with a temperature of 9,400 K (9,130 °C; 16,460 °F). It lies in the field of view of the Kepler Mission and was determined to have a companion object in orbit around it which is smaller and hotter than the main star.
KOI-74b is a hot compact object orbiting KOI-74. It was discovered in 2010 by the Kepler Mission and came to attention because of its small size (its radius is only 4.3% of the solar radius) and high temperature of 13,000 K (12,700 °C; 22,900 °F). The orbit of KOI-74b around the main star takes 5.18875 days to complete. Analysis of relativistic boosting of light in the Kepler data indicates that it is likely to be a low mass white dwarf of approximately 0.22 solar masses, resulting from an earlier phase of mass transfer in a binary system when the object underwent its giant phase.
- KOI-81, a similar system also discovered by the Kepler Mission.
- Kepler Object of Interest, stars observed to have transits by the Kepler Mission
- "NAME KOI-74 -- Star". SIMBAD. Retrieved 2010-06-19.
- "GSC2.3 N2J3000844". Guide Star Catalog 2.3. 2008. Retrieved 2010-06-19.
- 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:. Bibcode:2010ApJ...715...51V. doi:10.1088/0004-637X/715/1/51.
- 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:. Bibcode:2010ApJ...713L.150R. doi:10.1088/2041-8205/713/2/L150.
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