Astronomy:HD 199942
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 00m 03.99267s[1] |
| Declination | +07° 30′ 58.3018″[1] |
| Apparent magnitude (V) | 5.98[2] (6.23 + 8.13)[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[4] |
| Spectral type | F1Vp[3] or F1VgF1mA8[5] |
| B−V color index | 0.283±0.006[2] |
| Astrometry | |
| Radial velocity (Rv) | −26.2[2] km/s |
| Proper motion (μ) | RA: +40.810[1] mas/yr Dec.: +30.445[1] mas/yr |
| Parallax (π) | 17.7360 ± 0.4820[1] mas |
| Distance | 184 ± 5 ly (56 ± 2 pc) |
| Absolute magnitude (MV) | 1.59[2] |
| Orbit[6] | |
| Period (P) | 58.40 yr |
| Semi-major axis (a) | 0.295″ |
| Eccentricity (e) | 0.295 |
| Inclination (i) | 130.8° |
| Longitude of the node (Ω) | 192.0° |
| Periastron epoch (T) | 1959.09 |
| Argument of periastron (ω) (secondary) | 318.1° |
| Details | |
| A | |
| Mass | 1.65[7] M☉ |
| Radius | 1.97+0.07 −0.09[1] R☉ |
| Luminosity | 10.2±0.3[1] L☉ |
| Surface gravity (log g) | 3.94[7] cgs |
| Temperature | 7342+181 −115[1] K |
| Rotational velocity (v sin i) | 159[4] km/s |
| Age | 1.016[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 199942 is a binary star system in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.98.[2] The system is located at a distance of approximately 184 light years based on parallax, and it has an absolute magnitude of 1.59.[2] It is drifting closer with a radial velocity of −26 km/s.[2]
This system is moving through the galaxy at a velocity of 30.3 km/s relative to the Sun. Its galactic orbit carry it somewhere between 25100-22000 light years from the galactic core, and it'll come at its closest to the Sun 2.1 million years from now, at a distance of 124.0 light-years.[2]
The binary nature of this system was discovered in 1934 by G. P. Kuiper, who found the pair had an angular separation of 0.3″.[3] The pair orbit each other with a period of 58.4 years and an eccentricity of 0.295.[6] The primary component is of visual magnitude 6.23 and is a chemically-peculiar F-type main-sequence star with a class of F1Vp.[3] The companion is of magnitude 8.13.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 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.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 3.4 Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M
- ↑ 4.0 4.1 Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ Abt, H. A. (1981), "Visual multiples. VII - MK classifications", The Astrophysical Journal Supplement Series 45: 437, doi:10.1086/190719, Bibcode: 1981ApJS...45..437A.
- ↑ 6.0 6.1 Hartkopf, W. I. et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, http://www.astro.gsu.edu/wds/orb6.html, retrieved 2020-02-11.
- ↑ 7.0 7.1 7.2 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.
- ↑ "HD 199942". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+199942.
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