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{{short description|Star in the constellation Scutum}}
{{short description|Binary star system in the constellation Scutum}}
{{Starbox begin
{{Starbox begin
|name=WR 120
|name=WR 120
}}<!--
}}
{{Starbox image
{{Starbox image
| image = [[Image:V462SctLightCurve.png|250px]]
|image =
| caption = A near-infrared (2.033 micron) [[light curve]] for V462 Scuti, adapted from Chené and St-Louis (2007).<ref name="Chene"/> The left-most point shows the 3 sigma error bar.
|caption =
}}
}}
-->
{{Starbox observe
{{Starbox observe
|epoch=J2000
|epoch=J2000
|ra={{RA|18|41|00.86698}}<ref name=gaia/>
|ra={{RA|18|41|00.86698}}<ref name=gaia/>
|dec={{DEC|-4|26|14.47345}}<ref name=gaia/>
|dec={{DEC|-4|26|14.47345}}<ref name=gaia/>
|appmag_v=11.93
|appmag_v=11.93<ref name=UCAC4/>
|constell=[[Scutum]]}}
|constell=[[Scutum]]}}
{{Starbox character
{{Starbox character
|type=[[Wolf-Rayet star|Wolf-Rayet]]
|type=[[Wolf-Rayet star|Wolf-Rayet]]
|class=WN7w<ref name=hamann/>
|class=WN7w<ref name=hamann/> + WN3/4<ref name=shara/>
|b-v=1.04<ref name=ducati/>
|b-v=1.04<ref name=ducati/>
|u-b=0.13<ref name=ducati/>
|u-b=0.13<ref name=ducati/>
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{{Starbox astrometry
{{Starbox astrometry
|radial_v=
|radial_v=
|prop_mo_ra=
|prop_mo_ra=−0.489<ref name=edr3/>
|prop_mo_dec=
|prop_mo_dec=−2.524<ref name=edr3/>
|parallax=0.6369
|parallax=0.3246
|p_error=0.1552
|p_error=0.0541
|parallax_footnote=<ref name=gaia/>
|parallax_footnote=<ref name=edr3/>
|dist_pc=
|dist_pc={{val|1,500|640|360|fmt=commas}}<ref name=gemma/>
|absmag_v=−3.81<ref name=hamann/>}}
|absmag_v=−3.81<ref name=hamann/>
}}
{{Starbox detail
{{Starbox detail
|mass=7<ref name=hamann/>
|mass=7<ref name=hamann/>
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{{Starbox end}}
{{Starbox end}}


'''WR 120''' is a [[Wolf-Rayet star]] in the constellation of [[Scutum]], around 4,900 light years away. It is a hydrogen-free weak-lined WN7 star, and is a possible member of the cluster Dolidze 33.<ref name=":0"/> From our point of view, WR 120 is reddened by 4.82 magnitudes.<ref name="gemma"/>
'''WR 120''' is a binary containing two [[Wolf-Rayet star]]s in the constellation of [[Scutum]], around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33.<ref name=":0"/> From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.<ref name="gemma"/>


== Properties ==
== Properties ==
Analysis of WR 120's spectrum with PoWR shows that it has a temperature of around 50,000 Kelvins, and is losing mass at a rate of {{solar mass|{{val|10|e=-4.9}}}}/year, or 1 solar mass every 80,000 years, which is being carried away from the surface at a speed of 1,225 kilometres per second.<ref name="hamann" /> Taking its close distance into account, WR 120's luminosity turns out to be a mere {{solar luminosity|83,200|link=y}}, which would make it one of the dimmest WN stars known, and one of the only WN stars with a luminosity below {{solar luminosity|100,000|link=y}}. Using the Stefan-Boltzmann Law, a radius of {{solar radius|3.78}} is derived, and a "transformed" radius at an optical depth of 2/3, more comparable to other types of stars, is at about {{solar radius|6}}. Using the WR Luminosity-Mass ratio, WR 120 may have a mass of just {{solar mass|7}}, one of the lowest masses of any WR star. WR 120’s visual luminosity is {{solar luminosity|2,858|link=y}}, which is also on the lower end of WR visual luminosities.<ref name="hamann" />
Analysis of the primary's spectrum with PoWR shows that it has a temperature of around 50,000 Kelvins, and is losing mass at a rate of {{solar mass|{{val||e=-4.9}}}}/year, or 1 solar mass every 80,000 years, which is being carried away from the surface at a speed of 1,225 kilometres per second.<ref name="hamann" /> Taking its close distance into account, WR 120 A's luminosity turns out to be a mere {{solar luminosity|83,200|link=y}}, which would make it one of the dimmest WN stars known, and one of the only WN stars with a luminosity below {{solar luminosity|100,000|link=y}}. Using the Stefan-Boltzmann Law, a radius of {{solar radius|3.78}} is derived, and a "transformed" radius at an optical depth of 2/3, more comparable to other types of stars, is at about {{solar radius|6}}. Using the WR Luminosity-Mass ratio, WR 120 may have a mass of just {{solar mass|7}}, one of the lowest masses of any WR star. WR 120 A’s visual luminosity is {{solar luminosity|2,858|link=y}}, which is also on the lower end of WR visual luminosities.<ref name="hamann" />


WR 120 may be further away than just 1,500 pc from the Sun, as the distance measurement for the cluster of which it may be a member of, Dolidze 33, sits at nearly 3,000 pc.<ref name=":0" />
WR 120 is thought to be a member of Dolidze 33, an [[open cluster]] nearly 3,000 pc away.<ref name=":0" />

== Binarity ==
In 2021, WR 120 was revealed to be a binary star. Previously, it was thought to be a single WR star, but it is in fact a rare double Wolf-Rayet star. The companion (a WN3/4 WR star) is located approximately 1700 AU from the primary WN7 WR, and is about 2.1 magnitudes fainter than WR 120.


== References ==
== References ==
{{reflist|refs=<ref name=hamann>{{Cite journal|last=Hamann|first=W.-R.|last2=Gräfener|first2=G.|last3=Liermann|first3=A.|last4=Hainich|first4=R.|last5=Sander|first5=A. A. C.|last6=Shenar|first6=T.|last7=Ramachandran|first7=V.|last8=Todt|first8=H.|last9=Oskinova|first9=L. M.|date=2019-05-01|title=The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters|journal=Astronomy and Astrophysics|volume=625|pages=A57|arxiv=1904.04687|bibcode=2019A&A...625A..57H|doi=10.1051/0004-6361/201834850|issn=0004-6361}}</ref>
{{reflist|refs=<ref name=hamann>{{Cite journal|last1=Hamann|first1=W.-R.|last2=Gräfener|first2=G.|last3=Liermann|first3=A.|last4=Hainich|first4=R.|last5=Sander|first5=A. A. C.|last6=Shenar|first6=T.|last7=Ramachandran|first7=V.|last8=Todt|first8=H.|last9=Oskinova|first9=L. M.|date=2019-05-01|title=The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters|journal=Astronomy and Astrophysics|volume=625|pages=A57|arxiv=1904.04687|bibcode=2019A&A...625A..57H|doi=10.1051/0004-6361/201834850|s2cid=104292503 |issn=0004-6361}}</ref>


<ref name="gemma">{{cite journal|last1=Crowther|first1=Paul A.|last2=Rate|first2=Gemma|year=2020|title=Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes|journal=Monthly Notices of the Royal Astronomical Society|volume=493|issue=1|pages=1512–1529|arxiv=1912.10125|bibcode=2020MNRAS.493.1512R|doi=10.1093/mnras/stz3614|s2cid=209444955}}</ref>
<ref name="gemma">{{cite journal|last1=Crowther|first1=Paul A.|last2=Rate|first2=Gemma|year=2020|title=Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes|journal=Monthly Notices of the Royal Astronomical Society|volume=493|issue=1|pages=1512–1529|arxiv=1912.10125|bibcode=2020MNRAS.493.1512R|doi=10.1093/mnras/stz3614|doi-access=free |s2cid=209444955}}</ref>


<ref name="gaia">{{Cite journal|last=Gaia Collaboration|date=2018-04-01|title=VizieR Online Data Catalog: Gaia DR2 (Gaia Collaboration, 2018)|journal=VizieR Online Data Catalog|volume=1345|bibcode=2018yCat.1345....0G}}</ref>
<ref name=UCAC4>{{cite journal|author1=Zacharias, N.|title=The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)|journal=VizieR On-line Data Catalog|date=2012|bibcode=2012yCat.1322....0Z}}</ref>

<ref name="Chene">{{cite journal |last1=Chené |first1=André-Nicolas |title=The First Determination of the Rotation Rates of Wolf-Rayet Stars |journal=Massive Stars as Cosmic Engines, Proceedings IAU Symposium |date=2007 |volume=250 |pages=139–144 |doi=10.1017/S1743921308020425 |doi-access=free }}</ref>

<ref name="gaia">{{Cite journal|last=Gaia Collaboration|date=2018-04-01|title=VizieR Online Data Catalog: Gaia DR2 (Gaia Collaboration, 2018)|journal=VizieR Online Data Catalog|volume=1345|doi=10.26093/cds/vizier.1345 |bibcode=2018yCat.1345....0G}}</ref>

<ref name=edr3>{{cite Gaia EDR3|4256734875858811904}}</ref>


<ref name="ducati">{{Cite journal|last=Ducati|first=J. R.|date=2002|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system.|journal=VizieR Online Data Catalog|volume=2237|bibcode=2002yCat.2237....0D}}</ref>
<ref name="ducati">{{Cite journal|last=Ducati|first=J. R.|date=2002|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system.|journal=VizieR Online Data Catalog|volume=2237|bibcode=2002yCat.2237....0D}}</ref>


<ref name=":0">{{Cite journal|last=Rate|first=Gemma|last2=Crowther|first2=Paul A.|last3=Parker|first3=Richard J.|date=2020-06-01|title=Unlocking Galactic Wolf-Rayet stars with Gaia DR2 - II. Cluster and association membership|bibcode=2020MNRAS.495.1209R|journal=Monthly Notices of the Royal Astronomical Society|volume=495|pages=1209–1226|doi=10.1093/mnras/staa1290|issn=0035-8711}}</ref>
<ref name=":0">{{Cite journal|last1=Rate|first1=Gemma|last2=Crowther|first2=Paul A.|last3=Parker|first3=Richard J.|date=2020-06-01|title=Unlocking Galactic Wolf-Rayet stars with Gaia DR2 - II. Cluster and association membership|bibcode=2020MNRAS.495.1209R|journal=Monthly Notices of the Royal Astronomical Society|volume=495|issue=1 |pages=1209–1226|doi=10.1093/mnras/staa1290|doi-access=free |arxiv=2005.02533 |issn=0035-8711}}</ref>

<ref name=shara>{{Cite journal|last1=Shara|first1=Michael M.|last2=Howell|first2=Steve B.|last3=Furlan|first3=Elise|last4=Gnilka|first4=Crystal L.|last5=Moffat|first5=Anthony F. J.|last6=Scott|first6=Nicholas J.|last7=Zurek|first7=David|date=2022-01-01|title=A speckle-imaging search for close and very faint companions to the nearest and brightest Wolf-Rayet stars|bibcode=2022MNRAS.509.2897S|journal=Monthly Notices of the Royal Astronomical Society|volume=509|issue=2 |pages=2897–2907|doi=10.1093/mnras/stab2666|doi-access=free |arxiv=2109.06975 |issn=0035-8711}}</ref>



}}
}}
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[[Category:Wolf–Rayet stars]]
[[Category:Wolf–Rayet stars]]
[[Category:Objects with variable star designations]]
[[Category:Objects with variable star designations|Scuti, V462]]
[[Category:Scutum (constellation)]]
[[Category:Scutum (constellation)]]

Latest revision as of 02:40, 19 July 2024

WR 120

A near-infrared (2.033 micron) light curve for V462 Scuti, adapted from Chené and St-Louis (2007).[1] The left-most point shows the 3 sigma error bar.
Observation data
Epoch J2000      Equinox J2000
Constellation Scutum
Right ascension 18h 41m 00.86698s[2]
Declination −4° 26′ 14.47345″[2]
Apparent magnitude (V) 11.93[3]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WN7w[4] + WN3/4[5]
U−B color index 0.13[6]
B−V color index 1.04[6]
Astrometry
Proper motion (μ) RA: −0.489[7] mas/yr
Dec.: −2.524[7] mas/yr
Parallax (π)0.3246 ± 0.0541 mas[7]
Distanceapprox. 10,000 ly
(approx. 3,100 pc)
Absolute magnitude (MV)−3.81[4]
Details
Mass7[4] M☉
Radius3.78[4] R☉
Luminosity83,200[4] L☉
Temperature50,100[4] K
Other designations
MR 89, V462 Scuti, 2MASS J18410086-0426145
Database references
SIMBADdata

WR 120 is a binary containing two Wolf-Rayet stars in the constellation of Scutum, around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33.[8] From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.[9]

Properties

[edit]

Analysis of the primary's spectrum with PoWR shows that it has a temperature of around 50,000 Kelvins, and is losing mass at a rate of 10−4.9 M☉/year, or 1 solar mass every 80,000 years, which is being carried away from the surface at a speed of 1,225 kilometres per second.[4] Taking its close distance into account, WR 120 A's luminosity turns out to be a mere 83,200 L☉, which would make it one of the dimmest WN stars known, and one of the only WN stars with a luminosity below 100,000 L☉. Using the Stefan-Boltzmann Law, a radius of 3.78 R☉ is derived, and a "transformed" radius at an optical depth of 2/3, more comparable to other types of stars, is at about 6 R☉. Using the WR Luminosity-Mass ratio, WR 120 may have a mass of just 7 M☉, one of the lowest masses of any WR star. WR 120 A’s visual luminosity is 2,858 L☉, which is also on the lower end of WR visual luminosities.[4]

WR 120 is thought to be a member of Dolidze 33, an open cluster nearly 3,000 pc away.[8]

Binarity

[edit]

In 2021, WR 120 was revealed to be a binary star. Previously, it was thought to be a single WR star, but it is in fact a rare double Wolf-Rayet star. The companion (a WN3/4 WR star) is located approximately 1700 AU from the primary WN7 WR, and is about 2.1 magnitudes fainter than WR 120.

References

[edit]
  1. ^ Chené, André-Nicolas (2007). "The First Determination of the Rotation Rates of Wolf-Rayet Stars". Massive Stars as Cosmic Engines, Proceedings IAU Symposium. 250: 139–144. doi:10.1017/S1743921308020425.
  2. ^ a b Gaia Collaboration (2018-04-01). "VizieR Online Data Catalog: Gaia DR2 (Gaia Collaboration, 2018)". VizieR Online Data Catalog. 1345. Bibcode:2018yCat.1345....0G. doi:10.26093/cds/vizier.1345.
  3. ^ Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
  4. ^ a b c d e f g h Hamann, W.-R.; Gräfener, G.; Liermann, A.; Hainich, R.; Sander, A. A. C.; Shenar, T.; Ramachandran, V.; Todt, H.; Oskinova, L. M. (2019-05-01). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy and Astrophysics. 625: A57. arXiv:1904.04687. Bibcode:2019A&A...625A..57H. doi:10.1051/0004-6361/201834850. ISSN 0004-6361. S2CID 104292503.
  5. ^ Shara, Michael M.; Howell, Steve B.; Furlan, Elise; Gnilka, Crystal L.; Moffat, Anthony F. J.; Scott, Nicholas J.; Zurek, David (2022-01-01). "A speckle-imaging search for close and very faint companions to the nearest and brightest Wolf-Rayet stars". Monthly Notices of the Royal Astronomical Society. 509 (2): 2897–2907. arXiv:2109.06975. Bibcode:2022MNRAS.509.2897S. doi:10.1093/mnras/stab2666. ISSN 0035-8711.
  6. ^ a b Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D.
  7. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  8. ^ a b Rate, Gemma; Crowther, Paul A.; Parker, Richard J. (2020-06-01). "Unlocking Galactic Wolf-Rayet stars with Gaia DR2 - II. Cluster and association membership". Monthly Notices of the Royal Astronomical Society. 495 (1): 1209–1226. arXiv:2005.02533. Bibcode:2020MNRAS.495.1209R. doi:10.1093/mnras/staa1290. ISSN 0035-8711.
  9. ^ Crowther, Paul A.; Rate, Gemma (2020). "Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes". Monthly Notices of the Royal Astronomical Society. 493 (1): 1512–1529. arXiv:1912.10125. Bibcode:2020MNRAS.493.1512R. doi:10.1093/mnras/stz3614. S2CID 209444955.
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