HD 111395

HD 111395 is a single,[10] variable star in the northern constellation of Coma Berenices. It has the variable star designation LW Com, short for LW Comae Berenices;[4] HD 111395 is the Henry Draper Catalogue designation. The star has a yellow hue and is just bright enough to be barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.29.[2] Based upon parallax measurements, it is located at a distance of 55.8 light years from the Sun.[1] The star is drifting closer with a radial velocity of −8.9 km/s.[5] It is a member of the Eta Chamaeleontis stellar kinematic group.[11]

HD 111395
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension  12h 48m 47.04825s[1]
Declination +24° 50′ 24.8203″[1]
Apparent magnitude (V) 6.29[2]
Characteristics
Evolutionary stage main sequence
Spectral type G7V[3]
B−V color index 0.703±0.002[2]
Variable type BY Dra[4]
Astrometry
Radial velocity (Rv)−8.936±0.0064[5] km/s
Proper motion (μ) RA: −335.003[1] mas/yr
Dec.: −105.623[1] mas/yr
Parallax (π)58.4809 ± 0.0501[1] mas
Distance55.77 ± 0.05 ly
(17.10 ± 0.01 pc)
Absolute magnitude (MV)5.15[2]
Details
Mass1.08±0.04[6] M☉
Radius0.93±0.01[1] R☉
Luminosity0.799±0.001[1] L☉
Surface gravity (log g)4.543±0.05[6] cgs
Temperature5,649+38
−17[1] K
Metallicity [Fe/H]0.08±0.02[6] dex
Rotational velocity (v sin i)3.8±0.8[6] km/s
Age1.0[7] or 1.01−1.73[8] Gyr
Other designations
LW Com, BD+25°2568, FK5 3021, GJ 486.1, HD 111395, HIP 62523, HR 4864, SAO 82511[9]
Database references
SIMBADdata

This object is a G-type main-sequence star with a stellar classification of G7V.[3] It is a BY Draconis variable that varies in brightness by about 0.10 magnitude over a period of 15.8 days,[4] which is interpreted as the rotation period of the star. (Messina et al. (2003) suspect the actual rotation period may be half that: 7.9 days.[12]) It has an active chromosphere[13] and is a source for X-ray emission.[14]

The star is around a billion years old with a projected rotational velocity of 3.8 km/s.[6] It has slightly above solar metallicity − the term astronomers use for the relative abundance of elements other than hydrogen and helium. The mass of the star is 8% greater than the Sun,[6] but it has 93% of the Sun's radius.[1] It is radiating 80% of the luminosity of the Sun from its photosphere at an effective temperature of 5649 K.[1] An infrared excess indicates a cold debris disk is orbiting the star at a distance of 17.48 AU with a mean temperature of 60 K. The disk has an estimated mass of 5.86×10−6 M⊕.[7]

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. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  4. 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.
  5. Soubiran, C.; et al. (April 2013), "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release", Astronomy & Astrophysics, 552: 11, arXiv:1302.1905, Bibcode:2013A&A...552A..64S, doi:10.1051/0004-6361/201220927, A64
  6. McCarthy, Kyle; Wilhelm, Ronald J. (October 2014), "Characterizing the AB Doradus Moving Group via High-resolution Spectroscopy and Kinematic Traceback", The Astronomical Journal, 148 (4): 13, arXiv:1407.1076, Bibcode:2014AJ....148...70M, doi:10.1088/0004-6256/148/4/70, 70.
  7. Gáspár, András; et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637X/826/2/171.
  8. Vican, Laura (June 2012), "Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey", The Astronomical Journal, 143 (6): 135, arXiv:1203.1966, Bibcode:2012AJ....143..135V, doi:10.1088/0004-6256/143/6/135.
  9. "HD 111395". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-28.
  10. Fuhrmann, K.; et al. (2017), "Multiplicity among Solar-type Stars", The Astrophysical Journal, 836 (1): 139, Bibcode:2017ApJ...836..139F, doi:10.3847/1538-4357/836/1/139.
  11. Nakajima, Tadashi; Morino, Jun-Ichi (January 2012), "Potential Members of Stellar Kinematic Groups within 30 pc of the Sun", The Astronomical Journal, 143 (1): 2, Bibcode:2012AJ....143....2N, doi:10.1088/0004-6256/143/1/2.
  12. Messina, S.; et al. (November 2003), "Dependence of coronal X-ray emission on spot-induced brightness variations in cool main sequence stars", Astronomy and Astrophysics, 410: 671–684, Bibcode:2003A&A...410..671M, doi:10.1051/0004-6361:20031203.
  13. Strassmeier, K. G.; et al. (December 1997), "Photospheric and chromospheric activity of the bright and single G5 dwarf HR 4864 = HD 111395", Information Bulletin on Variable Stars, 4538: 1, Bibcode:1997IBVS.4538....1S.
  14. Greiner, J.; Richter, G. A. (March 2015), "Optical counterparts of ROSAT X-ray sources in two selected fields at low vs. high Galactic latitudes", Astronomy & Astrophysics, 575: 67, arXiv:1408.5529, Bibcode:2015A&A...575A..42G, doi:10.1051/0004-6361/201322844, A42.
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