9 Hydrae

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[1] mas
Distance212 ± 3 ly
(64.9 ± 0.9 pc)
Details
Mass1.72 ± 0.46[6] M☉
Radius11[5] R☉
Luminosity49[5] L☉
Surface gravity (log g)2.8[5] cgs
Temperature4688 ± 5[5] K
Metallicity [Fe/H]-0.01[5] dex
Other designations
BD−15° 2554, FK5 2684, HD 74137, HIP 42662, HR 3441, SAO 154552
Database references
SIMBADdata

9 Hydrae (9 Hya) is a star in the constellation Hydra. Its apparent magnitude is 4.87.

References

  1. 1 2 3 4 5 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.
  2. ↑ 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.
  3. ↑ 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.
  4. 1 2 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  5. 1 2 3 4 5 6 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.
  6. ↑ 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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