53 Ophiuchi

53 Ophiuchi is a multiple star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with a combined apparent visual magnitude of 5.80.^[3] Located around 370 light years distant from the Sun based on parallax,^[1] it is moving closer to the Earth with a heliocentric radial velocity of −14 km/s.^[5] As of 2011, the visible components had an angular separation of 41.28″ along a position angle of 190°.^[12] The primary may itself be a close binary system with a separation of 0.3692″ and a magnitude difference of 3.97 at an infrared wavelength of 562 nm.^[13]

53 Ophiuchi

Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus
Right ascension	17h 34m 36.69409s[1]
Declination	+09° 35′ 12.1005″[1]
Apparent magnitude (V)	5.80[2] (5.82 + 7.8)[3]
Characteristics
Spectral type	A2 V + A8 IV[4]
Astrometry
53 Oph A
Radial velocity (Rv)	−13.9±2.9[5] km/s
Proper motion (μ)	RA: +2.126[1] mas/yr Dec.: −8.530[1] mas/yr
Parallax (π)	8.8060 ± 0.0978 mas[1]
Distance	370 ± 4 ly (114 ± 1 pc)
53 Oph B
Proper motion (μ)	RA: +1.794[6] mas/yr Dec.: −8.148[6] mas/yr
Parallax (π)	8.8979 ± 0.0413 mas[6]
Distance	367 ± 2 ly (112.4 ± 0.5 pc)
Details
53 Oph Aa
Mass	2.50±0.05[7] M☉
Radius	1.7[8] R☉
Luminosity	56.4+5.3 −4.9[7] L☉
Surface gravity (log g)	3.90[9] cgs
Temperature	9,311+173 −170[7] K
Metallicity [Fe/H]	0.21[9] dex
Rotational velocity (v sin i)	29[7] km/s
53 Oph B
Radius	1.72+0.06 −0.03[6] R☉
Luminosity	7.74±0.05[6] L☉
Temperature	7,344+124 −152[6] K
Rotational velocity (v sin i)	140[4] km/s
Other designations
f Oph, 53 Oph, HD 159480, HIP 85998, HR 6548, WDS J17346+0935[10]
53 Oph A: BD+09°3424, GC 23824, SAO 122526[10]
53 Oph B: BD+09°3423, GC 23823, SAO 122525[11]
Database references
SIMBAD	data

The magnitude 5.82^[3] primary, designated component Aa, is an A-type main-sequence star with a stellar classification of A2 V.^[4] It has 2.5^[7] times the mass of the Sun and about 1.7^[8] times the Sun's radius. The star is radiating 56 times the Sun's luminosity from its photosphere at an effective temperature of 9,311 K.^[7] The widely spaced secondary, designated component B, is a magnitude 7.8^[3] A-type subgiant star with a class of A8 IV.^[4]

References

1. 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. 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.
3. 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.
4. Levato, H. (1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics, 19: 91, Bibcode:1975A&AS...19...91L.
5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
6. 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.
7. Zorec, J.; Royer, F.; Asplund, Martin; Cassisi, Santi; Ramirez, Ivan; Melendez, Jorge; Bensby, Thomas; Feltzing, Sofia (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
8. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (2) (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
9. Lemke, M. (November 1989), "Abundance anomalies in main sequence A stars. I. Iron and titanium", Astronomy and Astrophysics, 225: 125–136, Bibcode:1989A&A...225..125L.
10. "f Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-21.
11. "BD+09 3423". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-21.
12. Mason, Brian D.; et al. (August 2011), "Speckle Interferometry at the U.S. Naval Observatory. XVII.", The Astronomical Journal, 142 (2): 4, Bibcode:2011AJ....142...46M, doi:10.1088/0004-6256/142/2/46, S2CID 250806722, 46.
13. Horch, Elliott P.; et al. (February 2011), "Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June", The Astronomical Journal, 141 (2): 13, Bibcode:2011AJ....141...45H, doi:10.1088/0004-6256/141/2/45, 45.