69 Herculis
69 Herculis is a binary star[2] system in the northern constellation Hercules. It has the Bayer designation e Herculis, while 69 Herculis is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.63.[2] The distance to this system can be estimated from parallax measurements, which yields a range of 175 light years. It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 17h 17m 40.25427s[1] |
| Declination | +37° 17′ 29.3995″[1] |
| Apparent magnitude (V) | 4.63 (4.66 + 8.68)[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | A2V[3] |
| B−V color index | 0.043±0.003[4] |
| Astrometry | |
| Radial velocity (Rv) | −9.90±1.78[5] km/s |
| Proper motion (μ) | RA: −43.05[1] mas/yr Dec.: +64.36[1] mas/yr |
| Parallax (π) | 18.59 ± 0.33 mas[1] |
| Distance | 175 ± 3 ly (53.8 ± 1.0 pc) |
| Absolute magnitude (MV) | 0.99[4] |
| Details | |
| 69 Her A | |
| Mass | 2.12[6] M☉ |
| Radius | 2.2[7] R☉ |
| Luminosity | 36.64[4] L☉ |
| Surface gravity (log g) | 4.02[8] cgs |
| Temperature | 9,141[8] K |
| Metallicity [Fe/H] | 0.29[8] dex |
| Rotational velocity (v sin i) | 141[8] km/s |
| Age | 155[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The magnitude 4.66[2] primary, designated component A, is an A-type main-sequence star with a stellar classification of A2V.[3] It is 155[9] million years old with 2.12[6] times the mass of the Sun. The star is spinning with a projected rotational velocity of 155 km/s, which is creating an equatorial bulge that is 5% larger than the star's polar radius.[9] It is about 2.2[7] times the size of the Sun and is radiating 37[4] times the Sun's luminosity from its photosphere at an effective temperature of 9,141 K.[8]
The secondary, component B, is magnitude 8.68 star with an angular separation of 0.840″ from the primary, as of 2008.[2] X-ray emission has been detected from this system. As A-type stars are not expected to be X-ray sources, this emission is most likely coming from the companion.[11]
References edit
- ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d e Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- ^ 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 de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b 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, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (2) (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b c d e Erspamer, D.; North, P. (February 2003), "Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE", Astronomy and Astrophysics, 398 (3): 1121–1135, arXiv:astro-ph/0210065, Bibcode:2003A&A...398.1121E, doi:10.1051/0004-6361:20021711, S2CID 1109164.
- ^ a b c van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
- ^ "69 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-15.
- ^ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677−684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.