Delta Hydri

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δ Hydri
Hydrus constellation map.svg
Red circle.svg

Location of δ Hydri (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Hydrus
Right ascension 02h 21m 44.94286s[1]
Declination −68° 39′ 33.9038″[1]
Apparent magnitude (V) 4.09[2]
Spectral type A2V[3]
U−B color index +0.05[2]
B−V color index +0.03[2]
Radial velocity (Rv) +6.00[4] km/s
Proper motion (μ) RA: -49.95[1] mas/yr
Dec.: +2.48[1] mas/yr
Parallax (π) 23.35 ± 0.34[1] mas
Distance 140 ± 2 ly
(42.8 ± 0.6 pc)
Absolute magnitude (MV) 0.92[3]
Mass 2.25[5] M
Radius 2.3[5] R
Luminosity 39.52[3] L
Surface gravity (log g) 3.98[6] cgs
Temperature 9,880[6] K
Metallicity [Fe/H] +0.12[3] dex
Rotational velocity (v sin i) 162[6] km/s
Other designations
CPD−69° 113, FK5 1065, GC 2872, HIP 11001, HR 705, HD 15008, SAO 248545
Database references

Delta Hydri (δ Hyi) is a class A2V[3] (white main-sequence) star in the constellation Hydrus. Its apparent magnitude is 4.09[2] and it is approximately 140 light years away based on parallax.[1]


  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D. 
  3. ^ a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. Bibcode:2012AstL...38..331A. arXiv:1108.4971Freely accessible. doi:10.1134/S1063773712050015.  Vizier catalog entry
  4. ^ Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (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. Bibcode:2007AN....328..889K. arXiv:0705.0878Freely accessible. doi:10.1002/asna.200710776. 
  5. ^ a b 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. Bibcode:1999A&A...352..555A. arXiv:astro-ph/9911002Freely accessible.  Vizier catalog entry
  6. ^ a b c 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. Bibcode:2015ApJ...804..146D. arXiv:1501.03154Freely accessible. doi:10.1088/0004-637X/804/2/146.  Vizier catalog entry