Astronomy:KOI-81

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Short description: Eclipsing binary system
KOI-81
KOI-81LightCurve.png
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
Equinox J2000.0]] (ICRS)
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
Mass2.71+0.19−0.11[1] M☉
Radius2.93 ± 0.14[1] R☉
Luminosity77.3 ± 9.6[1] L☉
Temperature10000[1] K
Other designations
KIC 8823868, 2MASS J19350857+4501065, GSC2.3 N2K9001230
Database references
SIMBADdata

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]

KOI-81b

KOI-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

  • 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

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 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. doi:10.1088/0004-637X/715/1/51. Bibcode: 2010ApJ...715...51V. 
  2. ↑ 2.0 2.1 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (2003). "2MASS 19350857+4501065". 2MASS All-Sky Catalog of Point Sources. Bibcode: 2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=II/246/out&-c=293.785736%2b45.018494,eq=J2000,rs=0.005. Retrieved 2010-06-19. 
  3. ↑ 3.0 3.1 "GSC2.3 N2K9001230". Guide Star Catalog 2.3. http://gsss.stsci.edu/webservices/GSC2/GSC2DataReturn.aspx?RAH=&RAM=&RAS=&DSN=+&DD=&DM=&DS=&EQ=2000&SIZE=&SRCH=Radius&FORMAT=HTML&CAT=GSC23&HSTID=N2K9001230&GSC1ID=&RA=&DEC=&R1=&R2=&M1=&M2=&N=&CL=. 
  4. ↑ 4.0 4.1 Rowe, Jason F.; Borucki, William J.; Koch, David; Howell, Steve B.; Basri, Gibor; Batalha, Natalie; Brown, Timothy M.; Caldwell, Douglas et al. (2010). "Kepler Observations of Transiting Hot Compact Objects". The Astrophysical Journal Letters 713 (2): L150–L154. doi:10.1088/2041-8205/713/2/L150. Bibcode: 2010ApJ...713L.150R. 

Coordinates: Sky map 19h 35m 08.57s, +45° 01′ 06.6″




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