Kappa Coronae Borealis
  | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Corona Borealis[1] |
| Right ascension | 15h 51m 13.9313s[2] |
| Declination | +35° 39′ 26.574″[2] |
| Apparent magnitude (V) | +4.79[3] |
| Characteristics | |
| Evolutionary stage | red giant branch[4][2] |
| Spectral type | K0 III-IV[3] |
| B−V color index | 0.996±0.005[1] |
| Astrometry | |
| Radial velocity (Rv) | −25.16±0.13[5] km/s |
| Proper motion (μ) | RA: −8.669 mas/yr[2] Dec.: −348.350 mas/yr[2] |
| Parallax (π) | 33.3433±0.0800 mas[2] |
| Distance | 97.8 ± 0.2 ly (29.99 ± 0.07 pc) |
| Absolute magnitude (MV) | +2.37[1] |
| Details[4] | |
| Mass | 1.32±0.10 M☉ |
| Radius | 4.77±0.07 R☉ |
| Luminosity | 11.6±0.3 L☉ |
| Surface gravity (log g) | 3.15±0.14 cgs |
| Temperature | 4,870±47 K |
| Metallicity [Fe/H] | +0.13±0.03 dex |
| Other designations | |
| κ CrB, 11 CrB, HD 142091, HIP 77655, HR 5901, SAO 64948[6] | |
| Database references | |
| SIMBAD | data |
Kappa Coronae Borealis is a star in the northern constellation of Corona Borealis. Its name is a Bayer designation that is Latinized from κ Coronae Borealis, and abbreviated Kappa CrB or κ CrB. The star is visible to the naked eye with an apparent visual magnitude of +4.82.[3] Based on parallax measurements, it is located at a distance of 97.8 light-years (30.0 pc) from the Earth. The star is drifting closer to the Sun with a line of sight velocity component of −25 km/s.[5]
This is an evolved K-type star of spectral type K0 III-IV,[3] meaning it has completely exhausted its hydrogen supply at its core. Around 2.5 billion years old,[4] it was an A-type main sequence star.[7] It is 1.32 times as massive as the Sun and has expanded to 4.8 times the Sun's radius. The star is radiating 11.6 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,870 K.[4]
Dust disk
In March 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.[7] The disk extends out from 50 AU to 180 AU, and there is an estimated 0.016 M🜨 of dust.[8]
Planetary system
In October 2007, a giant planet was found by Johnson et al., who used the radial velocity method.[9] In 2012 it was confirmed.[3]
This planet was assumed to be outside the habitable zone on the assumption that the star is K1IVa.[10] Given the star's luminosity, the planet is more likely on the zone's inner edge.[11]
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.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | ≥1.811±0.057 MJ | 2.65±0.13 | 1285±14 | 0.167±0.032 | — | — |
See also
References
- 1 2 3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 3 4 5 Sato, Bun'ei; et al. (2012). "Substellar Companions to Seven Evolved Intermediate-Mass Stars". Publications of the Astronomical Society of Japan. 64 (6). 135. arXiv:1207.3141. Bibcode:2012PASJ...64..135S. doi:10.1093/pasj/64.6.135.
- 1 2 3 4 White, T. R.; et al. (July 2018). "Interferometric diameters of five evolved intermediate-mass planet-hosting stars measured with PAVO at the CHARA Array". Monthly Notices of the Royal Astronomical Society. 477 (4): 4403–4413. arXiv:1804.05976. Bibcode:2018MNRAS.477.4403W. doi:10.1093/mnras/sty898. S2CID 48365395.
- 1 2 Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
- ↑ "Kappa Coronae Borealis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-21.
- 1 2 3 Bonsor, Amy; et al. (2013). "Spatially resolved images of dust belt(s) around the planet-hosting subgiant κ CrB". MNRAS. 431 (4): 3025–3035. arXiv:1302.7000. Bibcode:2013MNRAS.431.3025B. doi:10.1093/mnras/stt367. S2CID 27703182.
- ↑ Lovell, J. B.; et al. (2022). "High-resolution ALMA and HST imaging of κ CrB: A broad debris disc around a post-main-sequence star with low-mass companions". Monthly Notices of the Royal Astronomical Society. 517 (2): 2546–2566. arXiv:2209.12910. Bibcode:2022MNRAS.517.2546L. doi:10.1093/mnras/stac2782.
- ↑ Johnson, John Asher; 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".
{{cite web}}: CS1 maint: deprecated archival service (link) - ↑ An earth-analogue should be slightly more than 3 AU away: square root of luminosity 12.9.
- ↑ Luhn, Jacob K.; et al. (2019). "Retired A Stars and Their Companions. VIII. 15 New Planetary Signals around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts". The Astronomical Journal. 157 (4). 149. arXiv:1811.03043. Bibcode:2019AJ....157..149L. doi:10.3847/1538-3881/aaf5d0. S2CID 102486961.
