6 Hydrae
{{Short description|Star in the constellation Hydra}}
{{about-distinguish|a Hydrae|33 Hydrae{{!}}A Hydrae|Alpha Hydrae{{!}}α Hydrae}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000.0
| constell = Hydra
| dec = {{DEC|−12|28|31.3433}}
}}
{{Starbox character
| type = giant
| variable =
}}
{{Starbox astrometry
| parallax = 8.7394
| p_error = 0.1769
}}
{{Starbox detail
| source =
| mass =
| radius = {{Val|32.7|0.5|2.6}}
| temperature = {{Val|4080|173|30|fmt=commas}}
| rotational_velocity =
| age_myr =
}}
{{Starbox catalog
| names = {{odlist | B=a Hya | F=6 Hya | BD=-11°2420 | HD=73840 | HIP=42509 | HR=3431 | SAO=154515 }}
}}
{{Starbox reference
| Simbad = 6+Hya
}}
{{Starbox end}}
6 Hydrae is a single star in the equatorial constellation of Hydra, located 373 light-years away from the Sun. It has the Bayer designation a Hydrae; 6 Hydrae is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.98. It is moving closer to the Earth with a heliocentric radial velocity of −8 km/s. Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.
This is an aging giant star with a stellar classification of K3 III, which indicates it has exhausted the hydrogen at its core and evolved away from the main sequence. As a consequence, it has expanded to 33 times the radius of the Sun. The star is radiating 267 times the luminosity of the Sun from its swollen photosphere at an effective temperature of {{val|4080|ul=K|fmt=commas}}.
References
{{reflist|refs=
{{cite DR2|5747442879511136640}}
{{cite simbad | title=6 Hya | access-date=2019-04-23 }}
| title=XHIP: An extended hipparcos compilation
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| journal=Astronomy Letters | postscript=.
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
| last=McWilliam | first=Andrew | postscript=.
| title=High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances
| journal=Astrophysical Journal Supplement Series
| volume=74 | pages=1075–1128 | date=December 1990
| doi=10.1086/191527 | bibcode=1990ApJS...74.1075M | doi-access=free }}
| last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C.
| title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project
| journal=Astronomy & Astrophysics
| volume=546 | id=A61 | pages=14 | date=October 2012
| doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D
| arxiv=1208.3048 | s2cid=59451347 | postscript=. }}
| title=A catalogue of multiplicity among bright stellar systems
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=389 | issue=2 | pages=869 | date=2008
| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | arxiv=0806.2878
| bibcode=2008MNRAS.389..869E | s2cid=14878976 | postscript=. }}
| title=Reality Tests of Superclusters in the Young Disk Population
| last1=Eggen | first1=Olin J.
| journal=Astronomical Journal | postscript=.
| volume=110 | page=2862 | date=December 1995
| doi=10.1086/117734 | bibcode=1995AJ....110.2862E }}
| last1=Houk | first1=Nancy | last2=Smith-Moore | first2=M.
| title=Michigan catalogue of two-dimensional spectral types for the HD stars
| volume=4 | publication-place=Ann Arbor | year=1978
| publisher=Dept. of Astronomy, University of Michigan
| bibcode=1988mcts.book.....H | postscript=. }}
}}
{{Stars of Hydra}}
{{DEFAULTSORT:6 Hydrae}}
Category:Hydra (constellation)