Astronomy:HD 49976
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Monoceros |
| Right ascension | 06h 50m 42.30314s[2] |
| Declination | –08° 02′ 27.5937″[2] |
| Apparent magnitude (V) | 6.16 to 6.32[3] |
| Characteristics | |
| Spectral type | A2p Sr Cr Eu[4] or B9V[5] |
| U−B color index | +0.02[6] |
| B−V color index | +0.00[6] |
| Variable type | α2 CVn[3] |
| Astrometry | |
| Radial velocity (Rv) | +19.2±2.4[7] km/s |
| Proper motion (μ) | RA: –9.794[2] mas/yr Dec.: +2.720[2] mas/yr |
| Parallax (π) | 9.6666 ± 0.0529[2] mas |
| Distance | 337 ± 2 ly (103.4 ± 0.6 pc) |
| Absolute magnitude (MV) | +1.13[8] |
| Details[8] | |
| Mass | 2.21±0.11 M☉ |
| Radius | 2.3±0.3 R☉ |
| Luminosity | 32 L☉ |
| Surface gravity (log g) | 4.04±0.13 cgs |
| Temperature | 9,016 K |
| Rotation | 2.976 days |
| Rotational velocity (v sin i) | 31[9] km/s |
| Age | 209[10] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 49976 is a variable star in the constellation of Monoceros (the Unicorn). It has the variable star designation V592 Monocerotis, while HD 49976 is the identifier from the Henry Draper Catalogue.[11] It has a white hue and is near the lower limit of visibility to the naked eye, having an apparent visual magnitude that fluctuates from 6.16 down to 6.32 with a 2.976 day period.[3] Based upon parallax measurements, it is located at a distance of approximately 337 light years from the Sun.[2] The star is drifting further away with a radial velocity of +19 km/s.[7]
This is a magnetic chemically peculiar star with a stellar classification of A2p Sr Cr Eu,[4] showing excesses in strontium and the rare earth elements in the photosphere, among others. Houk and Swift (1999) assigned it a class of B9V, matching a B-type main sequence star.[5] It is an Alpha2 Canum Venaticorum variable;[3] the magnetic field is complex; not corresponding to a simple dipole.[12]
HD 49976 is an estimated 209[10] million years old and is spinning with a period of 2.976 days.[8] The star has 2.2 times the mass of the Sun and 2.3 times the Sun's radius. It is radiating 32 times the luminosity of the Sun from its photosphere at an effective temperature of 9,016 K.[8]
References
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ 3.0 3.1 3.2 3.3 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.
- ↑ 4.0 4.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C
- ↑ 5.0 5.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode: 1999MSS...C05....0H.
- ↑ 6.0 6.1 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J
- ↑ 7.0 7.1 Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 8.0 8.1 8.2 8.3 North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics 334: 181–187, Bibcode: 1998A&A...334..181N
- ↑ Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, doi:10.1051/0004-6361:20020943, Bibcode: 2002A&A...393..897R
- ↑ 10.0 10.1 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal 804 (2): 146, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 11.0 11.1 "V592 Mon". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V592+Mon.
- ↑ Glagolevskij, Yu. V. et al. (October 2013), "Features of calcium and strontium distribution on the surface of CP star HD49976", Astrophysical Bulletin 68 (4): 454–460, doi:10.1134/S1990341313040068, Bibcode: 2013AstBu..68..454G
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