Astronomy:HD 111395
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[2] mas/yr Dec.: −105.517[2] mas/yr |
| Parallax (π) | 58.4858 ± 0.0293[2] mas |
| 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 |
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]
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 astronomical unit|AU with a mean temperature of 60 K. The disk has an estimated mass of 5.86×10−6 M⊕.[9]
References
- ↑ 1.0 1.1 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.
- ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 4.0 4.1 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, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ 5.0 5.1 5.2 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 6.0 6.1 Soubiran, C. et al. (April 2013), "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release", Astronomy & Astrophysics 552: 11, doi:10.1051/0004-6361/201220927, A64, Bibcode: 2013A&A...552A..64S
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 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, doi:10.1088/0004-6256/148/4/70, 70, Bibcode: 2014AJ....148...70M.
- ↑ 8.0 8.1 8.2 8.3 8.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 9.0 9.1 Gáspár, András et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal 826 (2): 171, doi:10.3847/0004-637X/826/2/171, Bibcode: 2016ApJ...826..171G.
- ↑ Vican, Laura (June 2012), "Age Determination for 346 Nearby Stars in the Herschel DEBRIS Survey", The Astronomical Journal 143 (6): 135, doi:10.1088/0004-6256/143/6/135, Bibcode: 2012AJ....143..135V.
- ↑ "HD 111395". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+111395.
- ↑ Fuhrmann, K. et al. (2017), "Multiplicity among Solar-type Stars", The Astrophysical Journal 836 (1): 139, doi:10.3847/1538-4357/836/1/139, Bibcode: 2017ApJ...836..139F.
- ↑ 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, doi:10.1088/0004-6256/143/1/2, Bibcode: 2012AJ....143....2N.
- ↑ 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, doi:10.1051/0004-6361:20031203, Bibcode: 2003A&A...410..671M.
- ↑ 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, doi:10.1051/0004-6361/201322844, A42, Bibcode: 2015A&A...575A..42G.
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