1 Boötis

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1 Boötis
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension  13h 40m 40.46926s[1]
Declination +19° 57′ 20.5839″[1]
Apparent magnitude (V) 5.71[2] (5.78 + 9.60)[3]
Spectral type A1 V[4] + Am[3]
U−B color index +0.02[2]
B−V color index +0.02[2]
Radial velocity (Rv)−26[5] km/s
Proper motion (μ) RA: −46.759[1] mas/yr
Dec.: +23.302[1] mas/yr
Parallax (π)10.2412 ± 0.0898[1] mas
Distance318 ± 3 ly
(97.6 ± 0.9 pc)
Absolute magnitude (MV)+0.79[6]
1 Boö A
Mass2.54 ± 0.09[6] M
Luminosity56[6] L
Temperature9,863[6] K
Rotational velocity (v sin i)60[4] km/s
Age323[6] Myr
1 Boö B
Mass1.02[6] M
Luminosity0.76[6] L
Temperature5,370[6] K
Other designations
BD+20°2858, HD 119055, HIP 66727, HR 5144, SAO 82942, CCDM J13407+1958, WDS J13407+1957[7]
Database references

1 Boötis (1 Boo) is a binary star[3] system in the northern constellation of Boötes, located 318 light years away from the Sun. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.71.[2] The pair had an angular separation of 4.660 as of 2008. It is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.[5]

The magnitude 5.78[3] primary component is an A-type main-sequence star with a stellar classification of A1 V.[4] This star has 2.5[6] times the mass of the Sun and is radiating 56[6] times the Sun's luminosity from its photosphere at an effective temperature of 9,863 K.[6] It is 323[6] million years old and is spinning with a projected rotational velocity of 60 km/s.[4]

The system is a source for X-ray emission, which is most likely coming from the companion star; this magnitude 9.60[3] component is a possible pre-main sequence star with a mass similar to the Sun. It is radiating 76% of the Sun's luminosity at an effective temperature of 6,370 K.[6]


  1. ^ a b c d e 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.
  2. ^ a b c d Lutz, T. E.; Lutz, J. H. (June 1977), "Spectral classification and UBV photometry of bright visual double stars", Astronomical Journal, 82: 431–434, Bibcode:1977AJ.....82..431L, doi:10.1086/112066
  3. ^ a b c d e 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.
  4. ^ a b c d Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224
  5. ^ a b Evans, D. S. (June 24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), The Revision of the General Catalogue of Radial Velocities, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
  6. ^ a b c d e f g h i j k l m Hubrig, S.; et al. (June 2001), "Search for low-mass PMS companions around X-ray selected late B stars", Astronomy and Astrophysics, 372: 152–164, arXiv:astro-ph/0103201, Bibcode:2001A&A...372..152H, doi:10.1051/0004-6361:20010452
  7. ^ "1 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-04-01.

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