Companion KOI-256 B | Constellation Cygnus | |
 | ||
People also search for Gliese 806, Omega1 Cygni, BD+40° 4210 | ||
Kesimpulan red dwarf koi 256 bangunkan einstein
KOI-256 is a double star located in the constellation Cygnus approximately 560 parsecs (1,828 ly) from Earth. While observations by the Kepler spacecraft suggested the system contained a gas giant exoplanet orbiting a red dwarf, later studies determined that KOI-256 was a binary system composed of the red dwarf orbiting a white dwarf.
Contents
Name
The acronym "KOI" comes from Kepler object of interest and means that the object has been cataloged by the Kepler spacecraft during its search for extrasolar planets using the transit method. The "256" is the number of the object.
Characteristics
Initial observations by the Kepler spacecraft suggested a central red dwarf with a mass of 0.65 M☉, a radius of 1.1 R☉, and a temperature of 3,639 K (3,366 °C; 6,091 °F). Its candidate exoplanet was estimated to have a mass of 14.8 M⊕, a radius of 25.34 R⊕, an orbital period of 1.38 days, a temperature of 1,160 K (890 °C; 1,630 °F), and a semi-major axis of 0.021 astronomical units. Further studies by Muirhead et al. (2012) refined the candidate exoplanet parameters to a radius of 7000559999999999999♠5.60±0.76 R⊕, a temperature of 726 K (453 °C; 847 °F), and a semi-major axis of 0.016 AU.
Muirhead et al. (2013) performed additional observations with the Hale Telescope at Palomar Observatory. Using the radial velocity method for exoplanet detection, Muirhead's team found that the red dwarf was wobbling too much to be caused by a planetary mass object, and was more likely being influenced by a white dwarf. Using ultraviolet data from the GALEX spacecraft, it was seen that the red dwarf was significantly active, further suggesting perturbations by a white dwarf. The team re-analyzed Kepler's data, and found that when the white dwarf passed in front of the red dwarf, the red dwarf's light noticeably warped and brightened, an effect called gravitational lensing. While only being slightly larger than the Earth, the white dwarf has such large mass that the physically larger red dwarf orbits around its smaller companion.
With the new observations, the red dwarf was shown to have a mass of 6999510000000000000♠0.51±0.15 M☉, a radius of 6999540000000000000♠0.540±0.014 R☉, and a temperature of 3,450 ± 50 K (3,180 ± 50 °C; 5,750 ± 90 °F). The white dwarf has a mass of 6999592000000000000♠0.592±0.084 M☉, a radius of 6998134500000000000♠0.01345±0.00091 R☉, and a temperature of 7,100 ± 800 K (6,800 ± 800 °C; 12,300 ± 1,400 °F).