Kappa Coronae Borealis
Epoch J2000.0 Equinox J2000.0
|Right ascension||15h 51m 13.9315s|
|Declination||+35° 39′ 26.575″|
|Apparent magnitude (V)||+4.79|
|Spectral type||K0 III-IV|
|Parallax (π)||32.13±0.61 mas|
|Mass||1.51 (1.32–1.70) M☉|
|Radius||5.0 (4.8–5.2) R☉|
|Surface gravity (log g)||3.21±0.08 cgs|
Kappa Coronae Borealis is a star approximately 102 light years away in the constellation of Corona Borealis.The apparent magnitude is +4.82 (4.17 trillion times fainter than the Sun) and the absolute magnitude is +2.35 (9.82 times brighter than the Sun). It is an orange K-type subgiant star of spectral type K1IV, meaning it has nearly completely exhausted its hydrogen supply in its core. It is 1.94 times as massive as the Sun yet has brightened to 12.5 times its luminosity. Around 2.5 billion years old, it was formerly an A-type main sequence star.
In March of 2013, it was announced that resolved images of at least one dust disk surrounding Kappa Coronae Borealis were captured, making it the first subgiant to host such circumstellar belt. The disk extends out to 120 AU.
The width of the circumstellar belt suggests the presence of a second planetary companion of the star, either within it or between two narrower belts.
(in order from star)
|b||>1.6 MJ||2.6||1251 ± 15||0.073 ± 0.049||—||—|
- Bun'ei Sato et al. (2012). "Substellar Companions to Seven Evolved Intermediate-Mass Stars". PASJ. arXiv:1207.3141. Bibcode:2012PASJ...64..135S. doi:10.1093/pasj/64.6.135.
- Pawellek, Nicole; Krivov, Alexander V.; Marshall, Jonathan P.; Montesinos, Benjamin; Ábrahám, Péter; Moór, Attila; Bryden, Geoffrey; Eiroa, Carlos (2014). "Disk Radii and Grain Sizes in Herschel-resolved Debris Disks". The Astrophysical Journal 792 (1): 19. Bibcode:2014ApJ...792...65P. doi:10.1088/0004-637X/792/1/65. 65.
- Bonsor, Amy; et al. (2013). "Spatially resolved images of dust belt(s) around the planet-hosting subgiant κ CrB". MNRAS 431: 3025–3035. arXiv:1302.7000. Bibcode:2013MNRAS.431.3025B. doi:10.1093/mnras/stt367.
- Johnson et al. (2008). "Retired A Stars and Their Companions. II. Jovian Planets Orbiting κ CrB and HD 167042". The Astrophysical Journal 675 (1): 784–789. arXiv:0711.4367. Bibcode:2008ApJ...675..784J. doi:10.1086/526453.
- "Planet kappa CrB b".
- An earth-analogue should be slightly more than 3 AU away: square root of luminosity 12.9.