Astronomy:Phi Herculis
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Short description: Star in the constellation Hercules
 φ Herculis in optical light | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hercules |
| Right ascension | 16h 08m 46.17745s[1] |
| Declination | +44° 56′ 05.6663″[1] |
| Apparent magnitude (V) | 4.24[2] |
| Characteristics | |
| Spectral type | B9VspHgMn[3] + A8V[4] |
| U−B color index | −0.23[2] |
| B−V color index | −0.06[2] |
| Variable type | α2 CVn?[5] |
| Astrometry | |
| Radial velocity (Rv) | −16.3±0.4[6] km/s |
| Proper motion (μ) | RA: −26.63[1] mas/yr Dec.: +36.76[1] mas/yr |
| Parallax (π) | 15.99 ± 0.45[1] mas |
| Distance | 204 ± 6 ly (63 ± 2 pc) |
| Absolute magnitude (MV) | A: 0.100 ± 0.059 B: 2.670 ± 0.074[7] |
| Orbit[7] | |
| Period (P) | 564.834±0.038 d |
| Semi-major axis (a) | 32.027±0.028 mas |
| Eccentricity (e) | 0.52614±0.00086 |
| Inclination (i) | 9.1±0.4° |
| Longitude of the node (Ω) | 190.4±1.4° |
| Periastron epoch (T) | 2450121.43 ± 0.20 JD |
| Argument of periastron (ω) (secondary) | 350.3±1.4° |
| Semi-amplitude (K1) (primary) | 2.772±0.073 km/s |
| Semi-amplitude (K2) (secondary) | 8.1[4] km/s |
| Details | |
| φ Her A | |
| Mass | 3.05±0.24[7] M☉ |
| Luminosity | 72[8] L☉ |
| Surface gravity (log g) | 4.05±0.15[4] cgs |
| Temperature | 11,525±150[4] K |
| Metallicity [Fe/H] | −0.03[7] dex |
| Rotational velocity (v sin i) | 8.0±1.0[4] km/s |
| Age | 210[7] Myr |
| φ Her B | |
| Mass | 1.614±0.066[7] M☉ |
| Surface gravity (log g) | 4.30±0.15[4] cgs |
| Temperature | 8,000±150[4] K |
| Rotational velocity (v sin i) | 50.0±3.0[4] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Phi Herculis (φ Her) is a binary star[4] system in the northern constellation of Hercules. Based upon an annual parallax shift of 15.99 mas as seen from Earth,[1] it is located around 204 light years from the Sun. With a combined apparent visual magnitude of 4.24,[2] it is bright enough to be seen with the naked eye.
This is a single-lined spectroscopic binary star system with an orbital period of 564.8 days and an eccentricity of 0.526.[7] The primary, component A, is a B-type main sequence star with a stellar classification of B9VspHgMn.[3] It is a chemically peculiar star of the type called a mercury-manganese star.[4] The star is tentatively catalogued as an Alpha2 Canum Venaticorum variable, with brightness variations of just 0.01 magnitudes.[5][12]
The secondary, component B, was first separated via interferometry in 2004.[13] It is an A-type main sequence star of class A8V.[4] The magnitude difference between the two components is 2.64.[13]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M.
- ↑ 3.0 3.1 Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement 99: 135, doi:10.1086/192182, Bibcode: 1995ApJS...99..135A.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Zavala, R. T. et al. (February 2007), "The Mercury-Manganese Binary Star φ Herculis: Detection and Properties of the Secondary and Revision of the Elemental Abundances of the Primary", The Astrophysical Journal 655 (2): 1046–1057, doi:10.1086/510108, Bibcode: 2007ApJ...655.1046Z.
- ↑ 5.0 5.1 Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Torres, Guillermo (June 2007), "Astrometric-Spectroscopic Determination of the Absolute Masses of the HgMn Binary Star φ Herculis", The Astronomical Journal 133 (6): 2684–2695, doi:10.1086/516756, Bibcode: 2007AJ....133.2684T.
- ↑ McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ "phi Her". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=phi+Her.
- ↑ Kochukhov, O.; Khalack, V.; Kobzar, O.; Neiner, C.; Paunzen, E.; Labadie-Bartz, J.; David-Uraz, A. (October 2021), "TESS survey of rotational and pulsational variability of mercury–manganese stars", Monthly Notices of the Royal Astronomical Society 506 (4): 5328–5344, doi:10.1093/mnras/stab2107.
- ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 8 December 2021.
- ↑ Kazarovets, E. V. et al. (1999), "The 74th Special Name-list of Variable Stars", Information Bulletin on Variable Stars 4659 (4659): 1, Bibcode: 1999IBVS.4659....1K.
- ↑ 13.0 13.1 Zavala, R. T. et al. (December 2004), "Detection of the Secondary of the HgMn star Phi Herculis with the Navy Prototype Optical Interferometer", Bulletin of the American Astronomical Society 36: 1527, Bibcode: 2004AAS...20510715Z.
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