HD 111395 is a single,[12] variable star in the northern constellation of Coma Berenices. It has the variable star designation LW Com, short for LW Comae Berenices;[5] 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.[3] Based upon parallax measurements, it is located at a distance of 55.8 light years from the Sun.[2] The star is drifting closer with a radial velocity of −8.9 km/s.[6] It is a member of the Eta Chamaeleontis stellar kinematic group.[13]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 12h 48m 47.048s[2] |
| Declination | +24° 50′ 24.82″[2] |
| Apparent magnitude (V) | 6.29[3] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | G7V[4] |
| B−V color index | 0.703±0.002[3] |
| Variable type | BY Dra[5] |
| Astrometry | |
| Radial velocity (Rv) | −8.936±0.0064[6] km/s |
| Proper motion (μ) | RA: −334.908 mas/yr[2] Dec.: −105.517 mas/yr[2] |
| Parallax (π) | 58.4858 ± 0.0293 mas[2] |
| Distance | 55.77 ± 0.03 ly (17.098 ± 0.009 pc) |
| Absolute magnitude (MV) | 5.15[3] |
| Details | |
| Mass | 1.08±0.04[7] M☉ |
| Radius | 0.93±0.01[8] R☉ |
| Luminosity | 0.799±0.001[8] L☉ |
| Surface gravity (log g) | 4.543±0.05[7] cgs |
| Temperature | 5,649+38 −17[8] K |
| Metallicity [Fe/H] | 0.08±0.02[7] dex |
| Rotational velocity (v sin i) | 3.8±0.8[7] km/s |
| Age | 1.0[9] or 1.01−1.73[10] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This object is a G-type main-sequence star with a stellar classification of G7V.[4] It is a BY Draconis variable that varies in brightness by about 0.10 magnitude over a period of 15.8 days,[5] 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.[14]) It has an active chromosphere[1] and is a source for X-ray emission.[15]
The star is around a billion years old with a projected rotational velocity of 3.8 km/s.[7] 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,[7] but it has 93% of the Sun's radius.[8] It is radiating 80% of the luminosity of the Sun from its photosphere at an effective temperature of 5649 K.[8] 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🜨.[9]
References
edit- ^ a b 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.
- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c d 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.
- ^ a b 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, S2CID 119476992.
- ^ a b c 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, S2CID 125853869.
- ^ a b 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, S2CID 56094559, A64
- ^ a b c d e f 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, S2CID 119296096, 70.
- ^ 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.
- ^ a b 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, S2CID 119241004.
- ^ 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, S2CID 118539505.
- ^ "HD 111395". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-28.
- ^ 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.
- ^ 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.
- ^ 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 (2): 671–684, Bibcode:2003A&A...410..671M, doi:10.1051/0004-6361:20031203.
- ^ 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, S2CID 59501196, A42.