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{{Starbox observe
{{Starbox observe
| epoch = J2000
| epoch = J2000
| ra = {{RA|18|21|19.548}}<ref name=hipparcos/>
| ra = {{RA|18|21|19.548}}<ref name=hipparcos>{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653|author1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 }}</ref>
| dec = {{DEC|-16|22|16.0572}}<ref name=hipparcos/>
| dec = {{DEC|-16|22|16.0572}}<ref name=hipparcos/>
| appmag_v = 8.44<ref name=clark/>
| appmag_v = 8.44<ref name=clark>{{cite journal |journal = Astronomy & Astrophysics | date = 2012 |title=On the nature of the galactic early-B hypergiants | last1 = Clark | first1 = J. S. |last2 = Najarro |first2=F. |last3 = Negueruela | first3 = I. |last4 = Ritchie | first4 = B. W. |last5 = Urbaneja | first5 = M. A. |last6 = Howarth | first6 = I. D. | format = pdf | arxiv = 1202.3991v1 | doi = 10.1051/0004-6361/201117472 |volume = 541 | pages = A145 |bibcode = 2012A&A...541A.145C}}</ref>
| constell = [[Sagittarius (constellation)|Sagittarius]]
| constell = [[Sagittarius (constellation)|Sagittarius]]
}}
}}
{{Starbox character
{{Starbox character
| class = B6Ia<sup>+</sup><ref name=chentsov/> {{nowrap|(B2 - B8<ref name=mahy/>)}}
| class = B6Ia<sup>+</sup><ref name=chentsov>{{cite journal|last1=Chentsov|first1=E. L.|last2=Ermakov|first2=S. V.|last3=Klochkova|first3=V. G.|last4=Panchuk|first4=V. E.|last5=Bjorkman|first5=K. S.|last6=Miroshnichenko|first6=A. S.|title=An atlas of spectra of B6-A2 hypergiants and supergiants from 4800 to 6700Å|journal=Astronomy and Astrophysics|volume=397|issue=3|year=2003|pages=1035–1042|doi=10.1051/0004-6361:20021430|bibcode=2003A&A...397.1035C}}</ref> {{nowrap|(B2 - B8<ref name=mahy>{{cite journal|doi=10.1051/0004-6361/201628584|arxiv=1608.01087|title=Tracing back the evolution of the candidate LBV HD168625|journal=Astronomy & Astrophysics|year=2016|last1=Mahy|first1=L.|last2=Hutsemékers|first2=D.|last3=Royer|first3=P.|last4=Waelkens|first4=C.|bibcode = 2016A&A...594A..94M }}</ref>)}}
| b-v = +1.41<ref name=ducati/>
| b-v = +1.41<ref name=ducati/>
| u-b = +0.37<ref name=ducati/>
| u-b = +0.37<ref name=ducati>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|pages=0|author1=Ducati|first1=J. R.|year=2002}}</ref>
| j-k = 0.599
| j-k = 0.599
| variable = [[alpha cygni variable|alpha cygni]]<ref name=sterken/>
| variable = [[alpha cygni variable|alpha cygni]]<ref name=sterken>{{cite journal|bibcode=1999A&A...349..532S|title=Light variations of the blue hypergiants HD 168607 and HD 168625 (1973-1999)|journal=Astronomy and Astrophysics|volume=349|pages=532|author1=Sterken|first1=C.|last2=Arentoft|first2=T.|last3=Duerbeck|first3=H. W.|last4=Brogt|first4=E.|year=1999}}</ref>
}}
}}
{{Starbox astrometry
{{Starbox astrometry
| radial_v = -4.00<ref name=KharchenkoScholz2007/>
| radial_v = -4.00<ref name="KharchenkoScholz2007">{{cite journal|last1=Kharchenko|first1=N.V.|last2=Scholz|first2=R.-D.|last3=Piskunov|first3=A.E.|last4=Röser|first4=S.|last5=Schilbach|first5=E.|title=Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ∼55000 stars and mean radial velocities of 516 Galactic open clusters and associations|journal=Astronomische Nachrichten|volume=328|issue=9|year=2007|pages=889–896|doi=10.1002/asna.200710776|bibcode=2007AN....328..889K|arxiv = 0705.0878 }}</ref>
| prop_mo_ra = -0.71 ± 1.20<ref name=hipparcos/>
| prop_mo_ra = -0.71 ± 1.20<ref name=hipparcos/>
| prop_mo_dec = +0.01 ± 0.74<ref name=hipparcos/>
| prop_mo_dec = +0.01 ± 0.74<ref name=hipparcos/>
Line 43: Line 43:
'''HD 168625''' ('''V4030 Sgr''') is a blue [[hypergiant]] and candidate [[luminous blue variable]] located in the [[constellation]] of [[Sagittarius (constellation)|Sagittarius]] easy to see with [[amateur astronomy|amateur]] [[telescope]]s. It forms a [[double star|visual pair]] with the also blue hypergiant (and luminous blue variable) [[HD 168607]] and is located to the south-east of M17, the [[Omega Nebula]].
'''HD 168625''' ('''V4030 Sgr''') is a blue [[hypergiant]] and candidate [[luminous blue variable]] located in the [[constellation]] of [[Sagittarius (constellation)|Sagittarius]] easy to see with [[amateur astronomy|amateur]] [[telescope]]s. It forms a [[double star|visual pair]] with the also blue hypergiant (and luminous blue variable) [[HD 168607]] and is located to the south-east of M17, the [[Omega Nebula]].


Its distance and association with that nebula and the mentioned star is dubious; while some authors think both stars are physically associated and belong to the [[stellar association]] [[Serpens OB1]],<ref name=Chentsov2004>
Its distance and association with that nebula and the mentioned star is dubious; while some authors think both stars are physically associated and belong to the [[stellar association]] [[Serpens OB1]],<ref name=Chentsov2004/> at a distance to the [[Sun]] of 2.2 kilo[[parsec]]s (7.200 [[light year]]s),<ref name=Naze2011/> others think HD 168625 is farther, at a distance estimated to be 2.8 kilo[[parsec]]s (9,100 [[light year]]s) and unrelated to the former objects.<ref name=Pasquali2002/>

== Physical characteristics ==

Assuming a distance of 2.2 kilo[[parsec]]s, HD 168625 is 220,000 times brighter than the [[Sun luminosity|Sun]], having a [[surface temperature (star)|surface temperature]] of 12,000 [[Kelvin|K]].<ref name=Naze2011/> It is losing mass through a very strong [[stellar wind]] at a rate of roughly 1.46×10<sup>−6</sup> [[solar mass]]es per year<ref name=Umana2010/> and observations realized in 2012 with the help of the [[Very Large Telescope|VLT]] show it's actually a [[binary star]],<ref name=Martayan2012/> with the companion being around 4.5 [[magnitude (astronomy)|magnitude]]s fainter than the primary.<ref name=Martayan2016/>

However, its most notable characteristic is the presence of a [[nebula]] surrounding it that was discovered in 1994<ref name=Hutsemekers1994/> and that has been studied with the help of several instruments and observatories and telescopes that include among others the [[Hubble Space Telescope]]<ref name=Pasquali2002/> and the [[Very Large Telescope|VLT]].<ref name=Umana2010/>

Said studies show that HD 168625 is actually surrounded by two nebulae: an inner one that has an elliptical shape and a very complex structure that includes arcs and filaments,<ref name=Pasquali2002/> and a much larger outer one discovered with the help of the [[Spitzer Space Telescope]] that has a [[Bipolar nebula|bipolar shape]] and that looks like a clone of the one surrounding [[Sanduleak -69° 202]], the progenitor of the [[supernova]] [[1987A]] in the [[Large Magellanic Cloud]].<ref name=Smith2007/> This suggests Sanduleak -69° 202 was also a luminous blue variable as well as the possibility of HD 168625 exploding as a [[Type II supernova]] in the near future.<ref name=Smith2007/>

== References ==
{{reflist|refs=

<ref name=hipparcos>{{cite journal|bibcode=2007A&A...474..653V|title=Validation of the new Hipparcos reduction|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653|author1=Van Leeuwen|first1=F.|year=2007|doi=10.1051/0004-6361:20078357|arxiv = 0708.1752 }}</ref>

<ref name=clark>{{cite journal |journal = Astronomy & Astrophysics | date = 2012 |title=On the nature of the galactic early-B hypergiants | last1 = Clark | first1 = J. S. |last2 = Najarro |first2=F. |last3 = Negueruela | first3 = I. |last4 = Ritchie | first4 = B. W. |last5 = Urbaneja | first5 = M. A. |last6 = Howarth | first6 = I. D. | format = pdf | arxiv = 1202.3991v1 | doi = 10.1051/0004-6361/201117472 |volume = 541 | pages = A145 |bibcode = 2012A&A...541A.145C}}</ref>

<ref name=chentsov>{{cite journal|last1=Chentsov|first1=E. L.|last2=Ermakov|first2=S. V.|last3=Klochkova|first3=V. G.|last4=Panchuk|first4=V. E.|last5=Bjorkman|first5=K. S.|last6=Miroshnichenko|first6=A. S.|title=An atlas of spectra of B6-A2 hypergiants and supergiants from 4800 to 6700Å|journal=Astronomy and Astrophysics|volume=397|issue=3|year=2003|pages=1035–1042|doi=10.1051/0004-6361:20021430|bibcode=2003A&A...397.1035C}}</ref>

<ref name=mahy>{{cite journal|doi=10.1051/0004-6361/201628584|arxiv=1608.01087|title=Tracing back the evolution of the candidate LBV HD168625|journal=Astronomy & Astrophysics|year=2016|last1=Mahy|first1=L.|last2=Hutsemékers|first2=D.|last3=Royer|first3=P.|last4=Waelkens|first4=C.|bibcode = 2016A&A...594A..94M }}</ref>

<ref name=ducati>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|pages=0|author1=Ducati|first1=J. R.|year=2002}}</ref>

<ref name=sterken>{{cite journal|bibcode=1999A&A...349..532S|title=Light variations of the blue hypergiants HD 168607 and HD 168625 (1973-1999)|journal=Astronomy and Astrophysics|volume=349|pages=532|author1=Sterken|first1=C.|last2=Arentoft|first2=T.|last3=Duerbeck|first3=H. W.|last4=Brogt|first4=E.|year=1999}}</ref>

<ref name=KharchenkoScholz2007>{{cite journal|last1=Kharchenko|first1=N.V.|last2=Scholz|first2=R.-D.|last3=Piskunov|first3=A.E.|last4=Röser|first4=S.|last5=Schilbach|first5=E.|title=Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ∼55000 stars and mean radial velocities of 516 Galactic open clusters and associations|journal=Astronomische Nachrichten|volume=328|issue=9|year=2007|pages=889–896|doi=10.1002/asna.200710776|bibcode=2007AN....328..889K|arxiv = 0705.0878 }}</ref>

<ref name=Chentsov2004>
{{cite journal
{{cite journal
|last1=Chentsov |first1=E.L. |last2=Gorda |first2=E.S.
|last1=Chentsov |first1=E.L. |last2=Gorda |first2=E.S.
Line 52: Line 79:
|bibcode=2004AstL...30..461C
|bibcode=2004AstL...30..461C
|doi=10.1134/1.1774398
|doi=10.1134/1.1774398
}}</ref>
}}</ref> at a distance to the [[Sun]] of 2.2 kilo[[parsec]]s (7.200 [[light year]]s),<ref name=Naze2011>

<ref name=Naze2011>
{{cite journal
{{cite journal
|last1=Nazé |first1=Y. |last2=Rauw |first2=G. |last3=Hutsemékers |first3=D.
|last1=Nazé |first1=Y. |last2=Rauw |first2=G. |last3=Hutsemékers |first3=D.
Line 61: Line 90:
|bibcode=2012A&A...538A..47N
|bibcode=2012A&A...538A..47N
|doi=10.1051/0004-6361/201118040
|doi=10.1051/0004-6361/201118040
|arxiv = 1111.6375 }}</ref>
|arxiv = 1111.6375 }}</ref> others think HD 168625 is farther, at a distance estimated to be 2.8 kilo[[parsec]]s (9,100 [[light year]]s) and unrelated to the former objects.<ref name=Pasquali2002>

<ref name=Pasquali2002>
{{cite journal
{{cite journal
|last1=Pasquali |first1=A. |last2=Nota |first2=A. |last3=Smith |first3=L.J. |last4=Akiyama |first4=S. |last5=Messineo |first5=M. |last6=Clampin |first6=M.
|last1=Pasquali |first1=A. |last2=Nota |first2=A. |last3=Smith |first3=L.J. |last4=Akiyama |first4=S. |last5=Messineo |first5=M. |last6=Clampin |first6=M.
Line 72: Line 103:
|arxiv = astro-ph/0207613 }}</ref>
|arxiv = astro-ph/0207613 }}</ref>


<ref name=Martayan2012>
== Physical characteristics ==

Assuming a distance of 2.2 kilo[[parsec]]s, HD 168625 is 220,000 times brighter than the [[Sun luminosity|Sun]], having a [[surface temperature (star)|surface temperature]] of 12,000 [[Kelvin|K]].<ref name=Naze2011/> It is losing mass through a very strong [[stellar wind]] at a rate of roughly 1.46×10<sup>−6</sup> [[solar mass]]es per year<ref name=Umana2010/> and observations realized in 2012 with the help of the [[Very Large Telescope|VLT]] show it's actually a [[binary star]],<ref name=Martayan2012>
{{cite journal
{{cite journal
|last1=Martayan |first1=C. |last2=Lobel |first2=A. |last3=Baade |first3=D. |last4=Blomme |first4=R. |last5=Frémat |first5=Y. |last6=Lebouquin |first6=J.-B. |last7=Selman |first7=F. |last8=Girard |first8=J. |last9=Mérand |first9=A. |last10=Montagnier |first10=G. |last11=Patru |first11=F. |last12=Mawet |first12=D. |last13=Martins |first13=F. |last14=Rivinius |first14=Th. |last15=Štefl |first15=S. |last16=Zorec |first16=J. |last17=Semaan |first17=T. |last18=Mehner |first18=A. |last19=Kervella |first19=P. |last20=Sana |first20=H. |last21=Schödel |first21=R. |date=2012
|last1=Martayan |first1=C. |last2=Lobel |first2=A. |last3=Baade |first3=D. |last4=Blomme |first4=R. |last5=Frémat |first5=Y. |last6=Lebouquin |first6=J.-B. |last7=Selman |first7=F. |last8=Girard |first8=J. |last9=Mérand |first9=A. |last10=Montagnier |first10=G. |last11=Patru |first11=F. |last12=Mawet |first12=D. |last13=Martins |first13=F. |last14=Rivinius |first14=Th. |last15=Štefl |first15=S. |last16=Zorec |first16=J. |last17=Semaan |first17=T. |last18=Mehner |first18=A. |last19=Kervella |first19=P. |last20=Sana |first20=H. |last21=Schödel |first21=R. |date=2012
Line 81: Line 110:
|volume=464 |pages=293
|volume=464 |pages=293
|bibcode=2012ASPC..464..293M
|bibcode=2012ASPC..464..293M
}}</ref>
}}</ref> with the companion being around 4.5 [[magnitude (astronomy)|magnitude]]s fainter than the primary.<ref name=Martayan2016>{{cite journal

<ref name=Martayan2016>{{cite journal
|last1=Martayan |first1=C. |last2=Lobel |first2=A. |last3=Baade |first3=D. |last4=Mehner |first4=A. |last5=Rivinius |first5=T. |last6=Boffin |first6=Henry M. J. |last7= Ronny |first7= B. |last8=Girard |first8=J. |last9=Mérand |first9=A. |last10=Montagnier |first10=G. |last11=Patru |first11=F. |last12=Mawet |first12=D. |last13=Martins |first13=F. |last14=Rivinius |first14=Th. |last15=Štefl |first15=S. |last16=Zorec |first16=J. |last17=Semaan |first17=T. |last18=Mehner |first18=A. |last19=Kervella |first19=P. |last20=Sana |first20=H. |last21=Schödel |first21=R. |date=2016
|last1=Martayan |first1=C. |last2=Lobel |first2=A. |last3=Baade |first3=D. |last4=Mehner |first4=A. |last5=Rivinius |first5=T. |last6=Boffin |first6=Henry M. J. |last7= Ronny |first7= B. |last8=Girard |first8=J. |last9=Mérand |first9=A. |last10=Montagnier |first10=G. |last11=Patru |first11=F. |last12=Mawet |first12=D. |last13=Martins |first13=F. |last14=Rivinius |first14=Th. |last15=Štefl |first15=S. |last16=Zorec |first16=J. |last17=Semaan |first17=T. |last18=Mehner |first18=A. |last19=Kervella |first19=P. |last20=Sana |first20=H. |last21=Schödel |first21=R. |date=2016
|title=Luminous blue variables: An imaging perspective on their binarity and near environment
|title=Luminous blue variables: An imaging perspective on their binarity and near environment
Line 89: Line 120:
|arxiv = 1601.03542 |doi = 10.1051/0004-6361/201526578 }}</ref>
|arxiv = 1601.03542 |doi = 10.1051/0004-6361/201526578 }}</ref>


<ref name=Hutsemekers1994>
However, its most notable characteristic is the presence of a [[nebula]] surrounding it that was discovered in 1994<ref name=Hutsemekers1994>
{{cite journal
{{cite journal
|last1=Hutsemekers |first1=D. |last2=vanDrom |first2=E. |last3=Gosset |first3=E. |last4=Melnick |first4=J.
|last1=Hutsemekers |first1=D. |last2=vanDrom |first2=E. |last3=Gosset |first3=E. |last4=Melnick |first4=J.
Line 97: Line 128:
|volume=2904 |pages=906–914
|volume=2904 |pages=906–914
|bibcode=1994A&A...290..906H
|bibcode=1994A&A...290..906H
}}</ref>
}}</ref> and that has been studied with the help of several instruments and observatories and telescopes that include among others the [[Hubble Space Telescope]]<ref name=Pasquali2002/> and the [[Very Large Telescope|VLT]].<ref name=Umana2010>

<ref name=Umana2010>
{{cite journal
{{cite journal
|last1=Umana |first1=G. |last2=Buemi |first2=C.S. |last3=Trigilio |first3=C. |last4=Leto |first4=P. |last5=Hora |first5=J.L.
|last1=Umana |first1=G. |last2=Buemi |first2=C.S. |last3=Trigilio |first3=C. |last4=Leto |first4=P. |last5=Hora |first5=J.L.
Line 108: Line 141:
}}</ref>
}}</ref>


<ref name=Smith2007>
Said studies show that HD 168625 is actually surrounded by two nebulae: an inner one that has an elliptical shape and a very complex structure that includes arcs and filaments,<ref name=Pasquali2002/> and a much larger outer one discovered with the help of the [[Spitzer Space Telescope]] that has a [[Bipolar nebula|bipolar shape]] and that looks like a clone of the one surrounding [[Sanduleak -69° 202]], the progenitor of the [[supernova]] [[1987A]] in the [[Large Magellanic Cloud]].<ref name=Smith2007>
{{cite journal
{{cite journal
|last1=Smith |first1=Nathan
|last1=Smith |first1=Nathan
Line 117: Line 150:
|bibcode=2007AJ....133.1034S
|bibcode=2007AJ....133.1034S
|doi=10.1086/510838
|doi=10.1086/510838
|arxiv = astro-ph/0611544 }}</ref>
|arxiv = astro-ph/0611544 }}</ref> This suggests Sanduleak -69° 202 was also a luminous blue variable as well as the possibility of HD 168625 exploding as a [[Type II supernova]] in the near future.<ref name=Smith2007/>


}}
== References ==
{{reflist}}


{{Stars of Sagittarius}}
{{Stars of Sagittarius}}

Revision as of 13:44, 3 August 2018

HD 168625
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 18h 21m 19.548s[1]
Declination −16° 22′ 16.0572″[1]
Apparent magnitude (V) 8.44[2]
Characteristics
Spectral type B6Ia+[3] (B2 - B8[4])
U−B color index +0.37[5]
B−V color index +1.41[5]
J−K color index 0.599
Variable type alpha cygni[6]
Astrometry
Radial velocity (Rv)-4.00[7] km/s
Proper motion (μ) RA: -0.71 ± 1.20[1] mas/yr
Dec.: +0.01 ± 0.74[1] mas/yr
Parallax (π)2.52 ± 1.10 mas[1]
Distance2,800[4] pc
Absolute magnitude (MV)−8.39[4]
Details[4]
Luminosity380,000 L
Surface gravity (log g)1.74 cgs
Temperature14,000 K
Rotational velocity (v sin i)60 km/s
Other designations
V4030 Sgr, HD 168625, BD -16°4830, SAO 161375, HIP 89963, AAVSO 1815-168
Database references
SIMBADdata
HD 168625 is the left star of the pair below the Omega Nebula. The other is the hypergiant HD 168607.

HD 168625 (V4030 Sgr) is a blue hypergiant and candidate luminous blue variable located in the constellation of Sagittarius easy to see with amateur telescopes. It forms a visual pair with the also blue hypergiant (and luminous blue variable) HD 168607 and is located to the south-east of M17, the Omega Nebula.

Its distance and association with that nebula and the mentioned star is dubious; while some authors think both stars are physically associated and belong to the stellar association Serpens OB1,[8] at a distance to the Sun of 2.2 kiloparsecs (7.200 light years),[9] others think HD 168625 is farther, at a distance estimated to be 2.8 kiloparsecs (9,100 light years) and unrelated to the former objects.[10]

Physical characteristics

Assuming a distance of 2.2 kiloparsecs, HD 168625 is 220,000 times brighter than the Sun, having a surface temperature of 12,000 K.[9] It is losing mass through a very strong stellar wind at a rate of roughly 1.46×10−6 solar masses per year[11] and observations realized in 2012 with the help of the VLT show it's actually a binary star,[12] with the companion being around 4.5 magnitudes fainter than the primary.[13]

However, its most notable characteristic is the presence of a nebula surrounding it that was discovered in 1994[14] and that has been studied with the help of several instruments and observatories and telescopes that include among others the Hubble Space Telescope[10] and the VLT.[11]

Said studies show that HD 168625 is actually surrounded by two nebulae: an inner one that has an elliptical shape and a very complex structure that includes arcs and filaments,[10] and a much larger outer one discovered with the help of the Spitzer Space Telescope that has a bipolar shape and that looks like a clone of the one surrounding Sanduleak -69° 202, the progenitor of the supernova 1987A in the Large Magellanic Cloud.[15] This suggests Sanduleak -69° 202 was also a luminous blue variable as well as the possibility of HD 168625 exploding as a Type II supernova in the near future.[15]

References

  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. ^ Clark, J. S.; Najarro, F.; Negueruela, I.; Ritchie, B. W.; Urbaneja, M. A.; Howarth, I. D. (2012). "On the nature of the galactic early-B hypergiants". Astronomy & Astrophysics. 541: A145. arXiv:1202.3991v1. Bibcode:2012A&A...541A.145C. doi:10.1051/0004-6361/201117472. {{cite journal}}: |format= requires |url= (help)
  3. ^ Chentsov, E. L.; Ermakov, S. V.; Klochkova, V. G.; Panchuk, V. E.; Bjorkman, K. S.; Miroshnichenko, A. S. (2003). "An atlas of spectra of B6-A2 hypergiants and supergiants from 4800 to 6700Å". Astronomy and Astrophysics. 397 (3): 1035–1042. Bibcode:2003A&A...397.1035C. doi:10.1051/0004-6361:20021430.
  4. ^ a b c d Mahy, L.; Hutsemékers, D.; Royer, P.; Waelkens, C. (2016). "Tracing back the evolution of the candidate LBV HD168625". Astronomy & Astrophysics. arXiv:1608.01087. Bibcode:2016A&A...594A..94M. doi:10.1051/0004-6361/201628584.
  5. ^ a b Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
  6. ^ Sterken, C.; Arentoft, T.; Duerbeck, H. W.; Brogt, E. (1999). "Light variations of the blue hypergiants HD 168607 and HD 168625 (1973-1999)". Astronomy and Astrophysics. 349: 532. Bibcode:1999A&A...349..532S.
  7. ^ Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ∼55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776.
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