51 Hydrae

{{Short description|Star in the constellation Hydra}}

{{about-distinguish2|k Hydrae|κ (kappa) Hydrae}}

{{Starbox begin}}

{{Starbox observe

| epoch = J2000

| constell = Hydra

| ra = {{RA|14|23|05.77393}}

| dec = {{DEC|−27|45|14.4609}}

| appmag_v = 4.78

}}

{{Starbox character

| type = giant

| class = K4 III

| b-v = {{Val|1.300|0.040}}

| u-b =

| variable =

}}

{{Starbox astrometry

| radial_v = {{Val|19.7|0.9}}

| prop_mo_ra = −202.476

| prop_mo_dec = −117.186

| parallax = 19.2042

| p_error = 0.2252

| parallax_footnote =

| absmag_v = 1.36

}}

{{Starbox detail

| source =

| mass = 1.31

| radius = {{Val|13.47|0.48|1.26}}

| luminosity = {{Val|54.9|0.8|1.5}}

| temperature = {{Val|4255|31|fmt=commas}}

| metal_fe = 0.08

| gravity = 2.25

| rotational_velocity =

| rotation =

| age_gyr =

}}

{{Starbox catalog

| names = {{odlist | B=k Hya | F=51 Hya | CD=-27°9803 | HD=125932 | HIP=70306 | HR=5381 | SAO=182483 | NSV=6648 }}

}}

{{Starbox reference

| Simbad=k+Hya

}}

{{Starbox end}}

51 Hydrae is a single star in the equatorial constellation of Hydra, located 170 light years away from the Sun. It has the Bayer designation k Hydrae; 51 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 4.78. It is moving further from the Earth with a heliocentric radial velocity of +20 km/s. Eggen (1971) listed it as a member of the η Cephei group of old-disk stars.

This is an evolved giant star with a stellar classification of K4 III, which indicates it has exhausted the supply of hydrogen at its core and expanded off the main sequence. It has 1.31 times the mass of the Sun but has swollen to 13.5 times the Sun's radius. The star is radiating 55 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,255 K.

References

{{reflist|refs=

{{cite DR2|6269720523431409536}}

{{cite simbad | title=k Hya | access-date=May 3, 2019 }}

{{citation

| 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 }}

{{citation

| title=Abundances in the Local Region. I. G and K Giants

| last1=Luck | first1=R. Earle

| journal=Astronomical Journal

| volume=150 | issue=3 | at=88 | year=2015

| arxiv=1507.01466 | bibcode=2015AJ....150...88L

| doi=10.1088/0004-6256/150/3/88 | s2cid=118505114 }}

{{citation

| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.

| title=A catalogue of multiplicity among bright stellar systems

| journal=Monthly Notices of the Royal Astronomical Society

| volume=389 | issue=2 | pages=869–879 | date=September 2008

| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | postscript=.

| bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}

{{citation

| last1=McWilliam | first1=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 }}

{{citation

| last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C.

| title=The Perkins Catalog of Revised MK Types for the Cooler Stars

| journal=The Astrophysical Journal Supplement Series

| volume=71 | pages=245 | year=1989

| bibcode=1989ApJS...71..245K | postscript=. | doi=10.1086/191373}}

{{citation

| title=The ζ Herculis, σ Puppis, ∈ Indi, and η Cephei Groups of Old Disk Population Stars

| last1=Eggen | first1=O. J. | postscript=.

| journal=Publications of the Astronomical Society of the Pacific

| volume=83 | issue=493 | page=251 | date=June 1971

| doi=10.1086/129119 | bibcode=1971PASP...83..251E | doi-access=free }}

}}

{{Stars of Hydra}}

{{DEFAULTSORT:51 Hydrae}}

Category:K-type giants

Category:Hydra (constellation)

Category:Durchmusterung objects