HD 96819 is a single[9] star in the equatorial constellation of Hydra. It was formerly known by its designation 10 Crateris, but that name fell into disuse after constellations were redrawn and the star was no longer in Crater. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.43.[3] Parallax measurements put it at a distance of 182 light years away from the Sun.[1] This is most likely (98.7% chance) a member of the TW Hydrae association.[7]

HD 96819
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra
Right ascension 11h 08m 43.99954s[1]
Declination −28° 04′ 50.4127″[2]
Apparent magnitude (V) 5.43[3]
Spectral type A1V[4]
U−B color index +0.06[5]
B−V color index +0.07[5]
Radial velocity (Rv)16.0±7.4[6] km/s
Proper motion (μ) RA: −72.79[2] mas/yr
Dec.: −22.16[2] mas/yr
Parallax (π)17.97 ± 0.53 mas[2]
Distance182 ± 5 ly
(56 ± 2 pc)
Absolute magnitude (MV)1.61[3]
Mass2.06±0.03[4] M
Radius1.9[3] R
Luminosity20.66[4] L
Surface gravity (log g)4.22±0.08[3] cgs
Temperature8,954[4] K
Rotational velocity (v sin i)249[4] km/s
Age9±1[7] Myr
Other designations
NSV 5101, CD−27°7886, HD 96819, HIP 54477, HR 4334, SAO 179577[8]
Database references

This is a rapidly rotating A-type main-sequence star that is about double the mass of the Sun. It emits 20.66 times as much energy as the Sun, at an effective temperature of 8,954 K. HD 96819 is currently 31.5% through its life as a main-sequence star: after that it will swell up as a red giant.[4] It is a young star of around nine million years age,[7] and is a suspected variable star.[10]


  1. ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d 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. S2CID 18759600.
  3. ^ a b c d e 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.
  4. ^ a b c d e f Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789.
  5. ^ 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.
  6. ^ Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID 119323941.
  7. ^ a b c Gagné, Jonathan; et al. (February 2017), "BANYAN. IX. The Initial Mass Function and Planetary-mass Object Space Density of the TW HYA Association", The Astrophysical Journal Supplement Series, 228 (2): 51, arXiv:1612.02881, Bibcode:2017ApJS..228...18G, doi:10.3847/1538-4365/228/2/18, S2CID 118920136, 18.
  8. ^ "HD 96819". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 August 2017.
  9. ^ 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.
  10. ^ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80−88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.