9 Boötis is a single,[8] variable star in the northern constellation of Boötes,[7] located around 630 light years away from the Sun.[1] It is visible to the naked eye as a faint, orange-hued star with a baseline apparent visual magnitude of 5.02.[2] This object is moving closer to the Earth with a heliocentric radial velocity of −41 km/s.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h 56m 34.18044s[1] |
| Declination | +27° 29′ 31.4851″[1] |
| Apparent magnitude (V) | 5.02[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K3 III[3] |
| B−V color index | 1.441±0.005[2] |
| Variable type | suspected irregular[4] |
| Astrometry | |
| Radial velocity (Rv) | −41.07±0.14[2] km/s |
| Proper motion (μ) | RA: +28.665[1] mas/yr Dec.: –47.779[1] mas/yr |
| Parallax (π) | 5.1990 ± 0.1461 mas |
| Distance | 630 ± 20 ly (192 ± 5 pc) |
| Absolute magnitude (MV) | −1.23[2] |
| Details | |
| Radius | 54.74+0.52 −2.22[1] R☉ |
| Luminosity | 716±24[1] L☉ |
| Surface gravity (log g) | 1.85[5] cgs |
| Temperature | 4,197[6] K |
| Metallicity [Fe/H] | −0.27[5] dex |
| Rotational velocity (v sin i) | 1.5[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K3 III,[3] which indicates it has exhausted the hydrogen at its core and evolved of the main sequence. As a consequence, its outer atmosphere has swollen to 55 times the radius of the Sun.[1] It is a suspected irregular variable that ranges in photographic magnitude from 6.1 down to 6.6.[4][9] 9 Boötis is considered mildly lithium-rich with a moderate level of chromospheric activity.[10] It is radiating 716[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,197 K.[6]
References
edit- ^ a b c d e f g h i Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f 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, S2CID 119257644.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373, ISSN 0067-0049.
- ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- ^ a b McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
- ^ a b c Rebull, Luisa M.; et al. (October 2015), "On Infrared Excesses Associated with Li-rich K Giants", The Astronomical Journal, 150 (4): 45, arXiv:1507.00708, Bibcode:2015AJ....150..123R, doi:10.1088/0004-6256/150/4/123, S2CID 46595131, 123.
- ^ a b "9 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 25, 2019.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ "NSV 6502", The International Variable Star Index, American Association of Variable Star Observers, retrieved 2019-04-26.
- ^ Fekel, Francis C.; Balachandran, Suchitra (February 1993), "Lithium and rapid rotation in chromospherically active single giants", Astrophysical Journal, Part 1, 403 (2): 708–721, Bibcode:1993ApJ...403..708F, doi:10.1086/172242.