WY Geminorum
{{short description|Binary star in the constellation Gemini}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = A visual band light curve for WY Geminorum, plotted from ASAS-SN data
}}
{{Starbox observe
| epoch = J2000.0
| constell = Gemini
| appmag_v = {{val|7.263|to|7.513}}
}}
{{Starbox character
| type =
| u-b =
| variable = Irregular variable + eclipsing binary
}}
{{Starbox astrometry
| prop_mo_ra = 0.450
| prop_mo_dec = −2.380
| parallax = 0.5169
| p_error = 0.0343
| absmag_v =
}}
{{Starbox orbit
| primary =
| name =
| period_unitless = {{cvt|23550|±|250|days|years|disp=out}}
| axis =
| axis_unitless = {{val|4.09|0.19|e=9|u=km|p=≥ }}
| eccentricity = 0.61{{±|0.03}}
| inclination =
| node =
| periastron = {{val|2445620|130|ul=JD|fmt=commas}}
| periarg = 57.5{{±|4.5}}
| periarg_primary =
| k1 = 16.0{{±|0.9}}
| k2 =
}}
{{Starbox detail
| source =
| component1 = Primary
| mass =
| luminosity =
| rotation =
| rotational_velocity =
| age_gyr =
}}
{{Starbox catalog
| names = {{odlist | V=WY Gem | BD=+23° 1243 | HD=42474 | HIP=29425 | PPM=95591 | SAO=78094 }}
}}
{{Starbox reference
| Simbad = WY+Gem
}}
{{Starbox end}}
WY Geminorum is a binary star system in the northern constellation of Gemini, abbreviated WY Gem. It has an apparent visual magnitude that ranges from 7.26 down to 7.51, which is too faint to be readily viewed with the naked eye. This system is located at a distance of approximately 6,300 light years from the Sun based on parallax measurements, and is receding with a radial velocity of 19.5 km/s.
In 1922, M. L. Humason found the spectrum of HD 42474 matches an M-type star, but with the peculiarity of numerous bright lines. It appears similar to the spectrum of VV Cephei (HR 8383), an eclipsing binary. P. Swings and O. Struve in 1941 discovered emission lines in the ultraviolet spectrum. The presence of a B-type stellar spectrum from a companion star was confirmed by W. P. Bidelman in 1954. The primary spectrum matches an M-type supergiant star. A. Cowley in 1970 found evidence of an atmospheric eclipse of the companion. In 1981, A. Buzzoni determined the primary to be a semi-regular variable of the SRb type with a period of 169 days.
This is a double-lined spectroscopic binary star system with an approximate orbital period of {{convert|23550|±|250|days|years|disp=out|abbr=off}} and a high eccentricity (ovalness) of 0.61. The primary component is an M-type supergiant star with a stellar classification of M2Ia or b. The companion is most likely a hotter B-type main-sequence star with a class of B2V. The pair are classified as a VV Cephei-type star system. The companion may be accreting matter from the supergiant around the time of periastron passage, resulting in the formation of an intermittent accretion disk orbiting the hotter star. Radio emission has been detected, which is most likely coming from an ionized region in the stellar wind of the supergiant.
References
{{reflist|refs=
| title=WY Gem
| access-date=2024-02-09
| postscript=. | mode = cs2 }}
{{Cite Gaia DR3 | 3425216631648846208}}
{{Cite Gaia DR2 | 3425216631648846208}}
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| title=XHIP: An extended hipparcos compilation
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
{{Cite web|url=https://www.chara.gsu.edu/files/2023Meeting/Norris_NMT_Students_2023.pdf|publisher=CHARA|title=Student Science at NMT: Learning Optical Interferometry Through Projects on Evolved Stars|author=Ryan Norris}}
| title=General Catalogue of Variable Stars
| display-authors=1 | last1=Samus | first1=N. N.
| last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V.
| last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N.
| version=GCVS 5.1 | journal=Astronomy Reports
| year=2017 | volume=61 | issue=1 | pages=80–88
| doi=10.1134/S1063772917010085
| bibcode=2017ARep...61...80S | s2cid=255195566
}}
| title=An M-Type Star Whose Spectrum Contains Bright Lines
| last=Humason | first=M. L.
| journal=Publications of the Astronomical Society of the Pacific
| volume=34 | issue=198 | page=133 | date=April 1922
| doi=10.1086/123170 | bibcode=1922PASP...34..133H | s2cid=119888135
}}
| title=The Emission Lines in the Spectra of B 1985 and WY Geminorum
| last1=Swings | first1=P. | last2=Struve | first2=O.
| journal=Astrophysical Journal
| volume=93 | page=455 | date=May 1941
| doi=10.1086/144287 | bibcode=1941ApJ....93..455S }}
| title=The spectrum of W Y Gem in the years 1967-68
| last=Martini | first=A.
| journal=Memorie della Società Astronomia Italiana
| volume=40 | page=25 | year=1969
| bibcode=1969MmSAI..40...25M }}
| title=WY Geminorum-An Eclipsing System?
| last=Cowley | first=Anne
| journal=Publications of the Astronomical Society of the Pacific
| volume=82 | issue=485 | page=329 | date=April 1970
| doi=10.1086/128912 | bibcode=1970PASP...82..329C }}
| title=WY Gem: a new semi-regular variable with a period of 169 days
| last=Buzzoni | first=A.
| journal=GEOS Circular on Semi-Regular Variables
| volume=SR 2 | date=November 1981
| bibcode=1981GEOCS...2.....B }}
| title=A spectroscopic study of the long-period binary star WY Geminorum
| last=Leedjaerv | first=Laurits
| journal=Astronomy and Astrophysics
| volume=338 | pages=139–150 | date=October 1998
| bibcode=1998A&A...338..139L }}
| title=The Radio Emission of VV Cephei-type Binaries
| last=Hjellming | first=R. M.
| journal=Radio Stars
| editor1-first=Robert M. | editor1-last=Hjellming
| editor2-first=David M. | editor2-last=Gobson
| isbn=90-277-2063-0 | series=Astrophysics and Space Science Library
| volume=116 | page=151 | date=July 1985
| doi=10.1007/978-94-009-5420-5_23 | bibcode=1985ASSL..116..151H }}
| title=Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters
| display-authors=1 | last1=Cenarro | first1=A. J.
| last2=Peletier | first2=R. F. | last3=Sánchez-Blázquez | first3=P.
| last4=Selam | first4=S. O. | last5=Toloba | first5=E.
| last6=Cardiel | first6=N. | last7=Falcón-Barroso | first7=J.
| first8=Gorgas | last8=J. | last9=Jiménez-Vicente | first9=J.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=374 | issue=2 | pages=664–690 |date=January 2007
| doi=10.1111/j.1365-2966.2006.11196.x | doi-access=free
| bibcode=2007MNRAS.374..664C
| arxiv=astro-ph/0611618 | s2cid=119428437 }}
| title=Variability survey of brightest stars in selected OB associations
| display-authors=1 | last1=Laur | first1=Jaan
| last2=Kolka | first2=Indrek | last3=Eenmäe | first3=Tõnis
| last4=Tuvikene | first4=Taavi | last5=Leedjärv | first5=Laurits
| journal=Astronomy & Astrophysics
| volume=598 | id=A108 | pages=27 | date=February 2017
| doi=10.1051/0004-6361/201629395 | bibcode=2017A&A...598A.108L
| arxiv=1611.02452 | s2cid=119076598 }}
| url=https://asas-sn.osu.edu/variables/lookup
| website=ASAS-SN Variable Stars Database
| title=ASAS-SN Variable Stars Database|publisher=ASAS-SN
| access-date=21 June 2024}}
}}
{{Gemini (constellation)}}
{{DEFAULTSORT:WY Geminorum}}
Category:B-type main-sequence stars
Category:Semiregular variable stars
Category:Spectroscopic binaries
Category:Astronomical radio sources