Astronomy:Phi3 Hydrae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 10h 38m 34.95281s[1] |
| Declination | −16° 52′ 35.6665″[1] |
| Apparent magnitude (V) | 4.90[2] |
| Characteristics | |
| Spectral type | G8 III[3] |
| B−V color index | 0.912[4] |
| Astrometry | |
| Radial velocity (Rv) | +17.45±0.70[5] km/s |
| Proper motion (μ) | RA: −98.92[1] mas/yr Dec.: +25.84[1] mas/yr |
| Parallax (π) | 15.49 ± 0.57[1] mas |
| Distance | 211 ± 8 ly (65 ± 2 pc) |
| Absolute magnitude (MV) | +0.89[6] |
| Orbit[2] | |
| Period (P) | 1200 d |
| Eccentricity (e) | 0.1 |
| Periastron epoch (T) | 2420760 JD |
| Argument of periastron (ω) (secondary) | 270° |
| Semi-amplitude (K1) (primary) | 4.0 km/s |
| Details | |
| φ3 Hya | |
| Mass | 2.04[3] M☉ |
| Radius | 9[4] R☉ |
| Luminosity | 48[3] L☉ |
| Surface gravity (log g) | 2.95[6] cgs |
| Temperature | 4,952±17[3] K |
| Metallicity [Fe/H] | −0.22±0.12[6] dex |
| Rotational velocity (v sin i) | 3.6[4] km/s |
| Age | 1.17[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Phi3 Hydrae (φ3 Hya) is a binary star[2] in the equatorial constellation of Hydra. It originally received the Flamsteed designation of 2 Crateris before being placed in the Hydra constellation.[8] Based upon an annual parallax shift of 15.49 mas as seen from Earth, it is located around 211 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of 4.90.[2] It forms a triangle with the fainter φ1 Hydrae and φ2 Hydrae, between μ Hydrae and ν Hydrae.
This is a single-lined spectroscopic binary star system with an orbital period of about 1,200 days and an eccentricity of 0.1.[2] The primary, component A, is an evolved G-type giant star with a stellar classification of G8 III.[3] It is a red clump star,[9] which means it is generating energy through the fusion of helium at its core. The star has twice[3] the mass of the Sun and has expanded to 9[4] times the Sun's radius. It is 1.17[3] billion years old and is radiating 48[3] times the solar luminosity from its photosphere at an effective temperature of 4,952 K.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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 2.4 Pourbaix, D. et al. (September 2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics 424: 727–732, doi:10.1051/0004-6361:20041213, Bibcode: 2004A&A...424..727P.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal 150 (3): 23, doi:10.1088/0004-6256/150/3/88, 88, Bibcode: 2015AJ....150...88L.
- ↑ 4.0 4.1 4.2 4.3 Massarotti, Alessandro et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 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.
- ↑ 6.0 6.1 6.2 McWilliam, Andrew (1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", The Astrophysical Journal Supplement Series 74: 1075, doi:10.1086/191527, Bibcode: 1990ApJS...74.1075M.
- ↑ "phi Hya". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=phi+Hya.
- ↑ Wagman, M. (August 1987), "Flamsteed's Missing Stars", Journal for the History of Astronomy 18 (3): 216, doi:10.1177/002182868701800305, Bibcode: 1987JHA....18..209W.
- ↑ Laney, C. D. et al. (January 2012), "A new Large Magellanic Cloud K-band distance from precision measurements of nearby red clump stars", Monthly Notices of the Royal Astronomical Society 419 (2): 1637–1641, doi:10.1111/j.1365-2966.2011.19826.x, Bibcode: 2012MNRAS.419.1637L.
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