9 Hydrae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 41m 43.33626s[1] |
| Declination | −15° 56′ 36.1846″[1] |
| Apparent magnitude (V) | 4.866[2] |
| Characteristics | |
| Spectral type | K0IIICNII[3] |
| U−B color index | +0.92[4] |
| B−V color index | +1.07[4] |
| Astrometry | |
| Radial velocity (Rv) | 0.17[5] km/s |
| Proper motion (μ) | RA: 3.71[1] mas/yr Dec.: -97.06[1] mas/yr |
| Parallax (π) | 15.40 ± 0.21 mas[1] |
| Distance | 212 ± 3 ly (64.9 ± 0.9 pc) |
| Details | |
| Mass | 1.72 ± 0.46[6] M☉ |
| Radius | 11[5] R☉ |
| Luminosity | 49[5] L☉ |
| Surface gravity (log g) | 2.8[5] cgs |
| Temperature | 4688 ± 5[5] K |
| Metallicity [Fe/H] | -0.01[5] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
9 Hydrae (9 Hya) is a star in the constellation Hydra. Its apparent magnitude is 4.87.
References
- ^ a b c d e van Leeuwen, F.; et al. (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.
- ^ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ Houk, N.; Smith-Moore, M. (1988). "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0". Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. 4. Bibcode:1988mcts.book.....H.
- ^ a b Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
- ^ a b c d e f Massarotti, Alessandro; Latham, David W.; Stefanik, Robert P.; Fogel, Jeffrey (2008). "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity". The Astronomical Journal. 135: 209. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209.
- ^ Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A.
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