88 Leonis

88 Leonis is a wide binary[5] star system in the equatorial constellation of Leo, the lion. The system is near the lower limit of visibility to the naked eye with an apparent visual magnitude of 6.27.[2] It is located at a distance of 77 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −4.8 km/s.[2] It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.379 arc seconds per annum.[11]

88 Leonis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Leo
Right ascension 11h 31m 44.94461s[1]
Declination +14° 21′ 52.2131″[1]
Apparent magnitude (V) 6.27[2] + 9.22[3]
Characteristics
Spectral type F9.5V[4] + G5[3]
B−V color index 0.570[2]
Astrometry
Radial velocity (Rv)−4.81±0.09[2] km/s
Proper motion (μ) RA: −330.279[1] mas/yr
Dec.: −190.081[1] mas/yr
Parallax (π)42.2619 ± 0.0812[1] mas
Distance77.2 ± 0.1 ly
(23.66 ± 0.05 pc)
Absolute magnitude (MV)4.46[2]
Details
88 Leo A
Mass1.06[5] M☉
Radius1.10+0.03
−0.05[1] R☉
Luminosity1.470±0.004[1] L☉
Surface gravity (log g)4.25[6] cgs
Temperature6,060+140
−76[1] K
Metallicity [Fe/H]−0.06±0.02[2] dex
Rotation14.32 days[7]
Age5.7+1.6
−3.1[2] Gyr
88 Leo B
Mass0.74[8] M☉
Other designations
STF 1547 AB, 88 Leonis, BD+15°2345, HD 100180, HIP 56242, HR 4437, WDS J11317+1422, Wolf 401[9]
88 Leo A: GJ 3669, SAO 99648, LTT 13145[9]
88 Leo B: GJ 3670, SAO 99647, LTT 13146[10]
Database references
SIMBADdata

The primary member of the system, component A, is a yellow-white hued F-type main-sequence star with a stellar classification of F9.5V.[4] It is an estimated 5.7[2] billion years old and is spinning with a rotation period of 14.3 days.[7] The star has a short magnetic activity cycle that averages around 3.5 years. A second cycle appears to vary over time, lasting 13.7 years at the start of observations then decreasing to 8.6 years over a span of 34 years of measurement.[7] The star has 1.06[5] times the mass of the Sun and 1.10[1] times the Sun's radius. It is radiating 1.47[1] times the luminosity of the Sun from its photosphere at an effective temperature of 6,060 K.[1]

The secondary, component B, is a magnitude 9.22[3] star at an angular separation of 15.46″ from the primary along a position angle of 326°.[8] It has a class of G5[3] and 74% of the Sun's mass. The pair share a common proper motion through space with a projected separation of 360.6 AU.[8]

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.
  3. Halbwachs, J. -L.; et al. (2017), "Double stars with wide separations in the AGK3 - II. The wide binaries and the multiple systems", Monthly Notices of the Royal Astronomical Society, 464 (4): 4966, arXiv:1610.04423, Bibcode:2017MNRAS.464.4966H, doi:10.1093/mnras/stw2683.
  4. Gray, R. O.; et al. (2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample", The Astronomical Journal, 132: 161, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  5. Halbwachs, J. -L; et al. (2018), "Multiplicity among solar-type stars. IV. The CORAVEL radial velocities and the spectroscopic orbits of nearby K dwarfs", Astronomy and Astrophysics, 619: A81, arXiv:1808.04605, Bibcode:2018A&A...619A..81H, doi:10.1051/0004-6361/201833377
  6. Hinkel, Natalie R.; et al. (October 2017), "A Catalog of Stellar Unified Properties (CATSUP) for 951 FGK-Stars within 30 pc", The Astrophysical Journal, 848 (1): 19, arXiv:1709.04465, Bibcode:2017ApJ...848...34H, doi:10.3847/1538-4357/aa8b0f, 34.
  7. Oláh, K.; et al. (July 2009), "Multiple and changing cycles of active stars. II. Results", Astronomy and Astrophysics, 501 (2): 703–713, arXiv:0904.1747, Bibcode:2009A&A...501..703O, doi:10.1051/0004-6361/200811304.
  8. Tokovinin, A.; Kiyaeva, O. (February 2016), "Eccentricity distribution of wide binaries", Monthly Notices of the Royal Astronomical Society, 456 (2): 2070–2079, arXiv:1512.00278, Bibcode:2016MNRAS.456.2070T, doi:10.1093/mnras/stv2825.
  9. "88 Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-05.
  10. "88 Leo B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-05.
  11. Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070, Bibcode:2005AJ....129.1483L, doi:10.1086/427854.
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