View source for Astronomy:OY Arae

{{short description|1910 nova in the constellation Ara}}
{{Starbox begin
| name = OY Arae
}}
{{Starbox image
| image=[[File:OYAraLightCurve.png|280px]]
| caption=A [[Astronomy:Light curve|light curve]] for OY Arae. The main plot (from data published by Walker and Shapley)<ref name="Walker"/> shows the 1910 eruption, and the inset plot (adapted from Zhao and McClintock)<ref name="Zhao"/> shows the eclipse light curve measured in 1995.
}}
{{Starbox observe
| epoch = J2000
| constell = [[Astronomy:Ara (constellation)|Ara]]
| ra = {{RA|16|40|50.456}}<ref name=GaiaDR3/>
| dec = {{DEC|-52|25|47.98}}<ref name=GaiaDR3/>
| appmag_v = 18.7<ref name=howell2018/>
}}
{{Starbox character
| class    = 
| b-v      = −0.15<ref name="Seitter"/>
| u-b      = 
| appmag_1_passband = B
| appmag_1 = 6.0{{snd}}18.6<ref name="IVSI"/>
| variable = [[Astronomy:Nova|Nova]] + [[Astronomy:Eclipsing binary|eclipsing]]<ref name="IVSI"/>
}}
{{Starbox astrometry
| prop_mo_ra = −3.689<ref name=GaiaDR3/>
| prop_mo_dec = −3.182<ref name=GaiaDR3/>
| parallax = 0.2676
| p_error = 0.0714
| parallax_footnote = <ref name=GaiaDR3/>
| absmag_v = −6.7 (at peak) 4.6 (quiescent)<ref name="Warner"/>
}}
{{Starbox orbit
| period_unitless = {{val|fmt=commas|3.72936|ul=hours}}<ref name=warren2021/>
| inclination = {{val|74.3|1.2}}<ref name="Zhao"/>
| axis_unitless = {{val|1.28|0.04|ul=solar radius}}<ref name="Zhao"/>
}}
{{Starbox detail
| component1 = white dwarf
| mass = {{val|0.82|0.12}}<ref name="Zhao"/>
| component2 = donor
| mass2 = {{val|0.34|0.01}}<ref name="Zhao"/>
}}
{{Starbox catalog
| names = {{odlist | name=Nova Arae 1910 |name2=HD 149990 |name3=[[Astronomy:2MASS|2MASS]] J16405045-5225479}} }}
{{Starbox reference
| Simbad = OY+Ara
}}
{{Starbox end}}

'''OY Arae''', also known as '''Nova Arae 1910''', is a [[Astronomy:Nova|nova]] in the constellation [[Astronomy:Ara (constellation)|Ara]]. It was discovered by Williamina Fleming on a [[Organization:Harvard College Observatory|Harvard Observatory]] [[Physics:Photographic plate#Astronomy|photographic plate]] taken on April 4, 1910.  At that time it had a magnitude of 6.0, making it faintly visible to the naked eye under ideal observing conditions. Examination of earlier plates showed that before the outburst it was a magnitude 17.5 object, and by March 19, 1910, it had reached magnitude 12.<ref name="Duerbeck"/><ref name="Zhao"/>

OY Arae is considered to be a moderately fast nova, because it faded by 3 magnitudes during the 83 days after discovery.<ref name="Duerbeck_2"/><ref name="Duerbeck"/> The light curve shows a secondary maximum in June 1910. The first spectrum of the nova was obtained on July 5, 1910, and resembled that of a gaseous nebula.<ref name="Cannon"/> An optical identification of the quiescent nova was made in 1994, and spectra taken at that time showed strong [[Physics:Balmer series|Balmer lines]] in [[Physics:Spectral line|emission]] atop a blue continuum.<ref name="Zhao"/>

All novae are binary stars, with a "donor" star orbiting a [[Astronomy:White dwarf|white dwarf]]. The two stars are so close to each other that material is transferred from the donor to the white dwarf. Because the distance between the two stars is comparable to the radius of the donor star, novae are often eclipsing binaries, and OY Arae does show eclipses. The primary eclipse, in which the donor star eclipses the white dwarf and its accretion disk, are about 2 magnitudes deep and last less than 30 minutes.  The orbital period is 3.73118 hours. The mass of the white dwarf is {{solar mass|{{val|0.82|0.12}}|link=y}}, and the mass of the donor star is {{solar mass|0.34±0.01|link=n}}. The two stars are separated by {{solar radius|{{val|1.28|0.04}}|link=y}}.<ref name="Zhao"/>

Most of the luminosity of the system is produced by the disk of material being stripped from the donor star.  This is estimated to be 7 magnitudes brighter than the donor star itself, with the white dwarf being even fainter.  The [[Astronomy:Absolute magnitude|absolute magnitude]] of the system is given as +4.6, but this value is distorted by the shape of the disk, seen nearly edge-on.  A mean absolute magnitude adjusted for viewing angle is +3.6.<ref name="Zhao"/>

==References==
{{reflist|refs=

<ref name=GaiaDR3>{{cite Gaia DR3|5931112341266390912}}</ref>

<ref name=howell2018>{{cite journal |bibcode=2018AJ....156..198H |title=On the M<SUB>V</SUB>-Inclination Relationship for Nova-like Variables |last1=Howell |first1=Steve B. |last2=Mason |first2=Elena |journal=The Astronomical Journal |year=2018 |volume=156 |issue=5 |page=198 |doi=10.3847/1538-3881/aadd13 |arxiv=1808.08170 |s2cid=54503839 |doi-access=free }}</ref>

<ref name="IVSI">{{cite web
 | title=OY Ara | url=https://www.aavso.org/vsx/index.php?view=detail.top&oid=3115
 | website=The International Variable Star Index | publisher=AAVSO | access-date=6 October 2022}}</ref>

<ref name=warren2021>{{cite journal |title=Nova-produced Common Envelope: Source of the Nonsolar Abundances and an Additional Frictional Angular Momentum Loss in Cataclysmic Variables |author1=Sparks, Warren M. |author2=Sion, Edward M. |journal=[[Astronomy:The Astrophysical Journal|The Astrophysical Journal]] |year=2021 |volume=914 |issue=1 |pages=16 |doi=10.3847/1538-4357/abf2bc |bibcode=2021ApJ...914....5S |arxiv=2103.14149 |s2cid=232380319 |doi-access=free }}</ref>

<ref name="Cannon">{{cite journal
 | last1=Cannon | first1=Annie Jump | last2=Pickering | first2=Edward Charles
 | title=Spectra having bright lines
 | journal=Annals of the Astronomical Observatory of Harvard College
 | date=1916 | volume=76 | issue=3 | pages=19–42 | bibcode=1916AnHar..76...19C }}</ref>

<ref name="Seitter">{{cite journal
 | last1=Duerbeck | first1=H. W. | last2=Seitter | first2=W. C.
 | title=A Survey of Nova Remnants
 | journal=Astrophysics and Space Science | date=March 1987 | volume=131
 | issue=1–2 | pages=467–473 | doi=10.1007/BF00668127 | bibcode=1987Ap&SS.131..467D }}</ref>

<ref name="Warner">{{cite journal
 | last1=Warner | first1=Brian
 | title=Absolute magnitudes of cataclysmic variables
 | journal=Monthly Notices of the Royal Astronomical Society
 | date=July 1987 | volume=227 | pages=23–73 | doi=10.1093/mnras/227.1.23 | bibcode=1987MNRAS.227...23W | doi-access=free }}</ref>

<ref name="Zhao">{{cite journal
 | last1=Zhao | first1=Ping | last2=McClintock | first2=Jeffrey E.
 | title=A Dynamical Study of the Eclipsing Nova OY Arae
 | journal=The Astrophysical Journal | date=July 1997 | volume=483 | issue=2
 | pages=899–906 | doi=10.1086/304283 | bibcode=1997ApJ...483..899Z | s2cid=119710755 | doi-access=free }}</ref>

<ref name="Walker">{{cite journal
 | last1=Walker | first1=Arville D. | last2=Shapley | first2=Harlow
 | title=The photographic light curves of thirteen novae
 | journal=Annals of Harvard College Observatory | bibcode=1933AnHar..84..189W
 | date=January 1933 | volume=84 | issue=7 | pages=189–206 }}</ref>

<ref name="Duerbeck">{{cite journal
 | title=A Reference Catalogue and Atlas of Galactic Novae
 | journal=Space Science Reviews | date=March 1987 | volume=45 | issue=1–2 | pages=1–14
 | doi=10.1007/BF00187826 | bibcode=1987SSRv...45....1D | s2cid=115854775 }}</ref>

<ref name="Duerbeck_2">{{cite journal
 | last1=Duerbeck | first1=H. W.
 | title=Light curve types, absolute magnitudes, and physical properties of galactic novae
 | journal=Publications of the Astronomical Society of the Pacific
 | date=April 1981 | volume=93 | pages=165–175 | doi=10.1086/130799 | bibcode=1981PASP...93..165D
 | s2cid=121397724 | doi-access=free }}</ref>

}}

{{Stars of Ara}}

[[Category:Novae]]
[[Category:Ara (constellation)]]
[[Category:Objects with variable star designations|Arae, OY]]

{{Sourceattribution|OY Arae}}