Epsilon Hydri
 
| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydrus |
| Right ascension | 02h 39m 35.36121s[1] |
| Declination | −68° 16′ 01.0103″[1] |
| Apparent magnitude (V) | 4.12[2] |
| Characteristics | |
| Spectral type | B9Va[2] |
| U−B color index | -0.14[3] |
| B−V color index | -0.06[3] |
| Astrometry | |
| Radial velocity (Rv) | +13.60[4] km/s |
| Proper motion (μ) | RA: +87.30[1] mas/yr Dec.: +0.09[1] mas/yr |
| Parallax (π) | 21.48 ± 0.09[1] mas |
| Distance | 151.8 ± 0.6 ly (46.6 ± 0.2 pc) |
| Absolute magnitude (MV) | 0.78[2] |
| Details | |
| Mass | 2.64[5] M☉ |
| Radius | 2.2[6] R☉ |
| Luminosity | 60[5] L☉ |
| Surface gravity (log g) | 4.33[7] cgs |
| Temperature | 10,970[7] K |
| Rotational velocity (v sin i) | 96[5] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Hydri (ε Hyi) is a class B9V[2] (blue main-sequence) star in the constellation Hydrus. Its apparent magnitude is 4.12[2] and it is approximately 151.8 light years away based on parallax.[1]
References
- 1 2 3 4 5 6 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752
. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry - 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. Vizier catalog entry
- 1 2 Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42: 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
- ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
- 1 2 3 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. Vizier catalog entry
- ↑ 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. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
- 1 2 David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. Vizier catalog entry
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