ρ Boötis
Diagram showing star positions and boundaries of the Boötes constellation and its surroundings
Location of ρ Boötes (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 14h 31m 49.78962s[1]
Declination +30° 22′ 17.1781″[1]
Apparent magnitude (V) 3.59[2]
Characteristics
Spectral type K4 III[3]
U−B color index +1.44[2]
B−V color index +1.30[2]
R−I color index 0.65
Astrometry
Radial velocity (Rv)−13.57±0.19[4] km/s
Proper motion (μ) RA: –100.90[1] mas/yr
Dec.: +120.73[1] mas/yr
Parallax (π)20.37 ± 0.18 mas[1]
Distance160 ± 1 ly
(49.1 ± 0.4 pc)
Absolute magnitude (MV)+0.27[3]
Details
Mass1.0–1.4[5] M☉
Radius21.57±0.25[5] R☉
Luminosity131.9±6.8[5] L☉
Surface gravity (log g)1.85±0.05[6] cgs
Temperature4,298±56[5] K
Metallicity [Fe/H]−0.19±0.10[6] dex
Age10.11±2.82[6] Gyr
Other designations
ρ Boo, 25 Boötis, BD+31°2628, FK5 534, HD 127665, HIP 71053, HR 5429, SAO 64202
Database references
SIMBADdata
ρ Boötis in optical light
A light curve for Rho Boötis, plotted from Hipparcos data[7]

Rho Boötis, Latinised from ρ Boötis, is a single,[8] orange-hued star in the northern constellation of Boötes. It is visible to the naked eye with an apparent visual magnitude of 3.59.[2] Based upon parallax measurements, it is located at a distance of approximately 160 light-years (49 parsecs) from Earth. It is moving toward the Sun with a radial velocity of −13.6 km/s.[4] There is an optical companion, a magnitude 11.5 star, located 34.7 arcseconds away along a position angle of 345° (as of 2013).[9]

This is an evolved K-type giant star, currently on the red-giant branch, with a stellar classification of K4 III[3] and an estimated age of 10[6] billion years. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[10] It has around 1.2[5] times the mass of the Sun and has expanded to 22[5] times the Sun's girth. The star is radiating 132[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 4,300 K.[5] Rho Boötis is classified as a RS Canum Venaticorum variable.[11] Koen and Eyer examined the Hipparcos data for this star, and found that it varied with a period of 5.214 days, and an amplitude of 0.0027 magnitudes.[12]

Nomenclature

Rho Boötis is known by several different names, including ρ Boo, 25 Boötis, BD+31° 2628, FK5 534, HD 127665, HIP 71053, HR 5429, and SAO 64202.[13] In Chinese, 梗河 (Gěng Hé), meaning Celestial Lance, refers to an asterism consisting of ρ Boötis, ε Boötis and σ Boötis.[14] Consequently, the Chinese name for ρ Boötis itself is 梗河三 (Gěng Hé sān, English: the Third Star of Celestial Lance).[15]

References

  1. 1 2 3 4 5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. 1 2 3 4 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
  3. 1 2 3 Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
  4. 1 2 Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209, S2CID 121883397.
  5. 1 2 3 4 5 6 7 8 Berio, P.; et al. (November 2011), "Chromosphere of K giant stars. Geometrical extent and spatial structure detection", Astronomy & Astrophysics, 535: A59, arXiv:1109.5476, Bibcode:2011A&A...535A..59B, doi:10.1051/0004-6361/201117479, S2CID 17171848.
  6. 1 2 3 4 Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy & Astrophysics, 574: A116, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360, hdl:10722/215277, S2CID 59334290.
  7. ↑ "/ftp/cats/more/HIP/cdroms/cats", Centre de Données astronomiques de Strasbourg, Strasbourg astronomical Data Center, retrieved 15 October 2022.
  8. ↑ 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.
  9. ↑ Mason, Brian D.; et al. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  10. ↑ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, archived from the original on June 25, 2019, retrieved February 4, 2012.
  11. ↑ "NSV 6697", The International Variable Star Index, AAVSO, retrieved 15 October 2022.
  12. ↑ Koen, Chris; Eyer, Laurent (March 2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. arXiv:astro-ph/0112194. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x.
  13. ↑ "HD 127665". SIMBAD. Archived from the original on July 30, 2021. Retrieved August 9, 2021.
  14. ↑ 陳久金 (2005), 中國星座神話 [Chinese Horoscope Myths] (in Chinese), 台灣書房出版有限公司, ISBN 978-986-7332-25-7.
  15. ↑ AEEA 天文教育資訊網 2006年6月29日 [AEEA Astronomy Education Information Network June 29, 2006] (in Chinese), AEEA Astronomy Education Information Network, June 29, 2006, archived from the original on June 5, 2021, retrieved August 9, 2021.
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