WR 25

{{Short description|Binary star system in the constellation Carina}}

{{Starbox begin

| name = WR 25

}}

{{Starbox image

| image=

{{Location mark

|image=Carina Nebula by ESO.jpg|alt=|float=center|width=280

|label=|position=right

|mark=Red circle.svg|mark_width=12|mark_link=WR 25

|x=582|y=740

}}

|caption=Location of WR 25 (circled)

|credit=ESO

}}

{{Starbox observe

| epoch = J2000.0

| equinox = J2000.0

| constell = Carina

| ra = {{RA|10|44|10.337}}{{cite journal |bibcode=1988A&AS...74..449R |title=A new star catalogue of SAO type |journal=Astronomy and Astrophysics Supplement Series |issn=0365-0138 |volume=74 |pages=449 |last1=Roeser |first1=S. |last2=Bastian |first2=U. |date=1988}}

| dec = {{DEC|-59|43|11.41}}

| appmag_v = 8.80{{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 |last1=Ducati |first1=J. R. |date=2002}}

}}

{{Starbox character

| type = Wolf-Rayet star

| class = O2.5If*/WN6 + OB{{cite journal |bibcode=2014ApJS..211...10S |title=The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars |journal=The Astrophysical Journal Supplement |volume=211 |issue=1 |pages=10 |last1=Sota |first1=A. |last2=Maíz Apellániz |first2=J. |last3=Morrell |first3=N. I. |author-link3=Nidia Morrell |last4=Barbá |first4=R. H. |last5=Walborn |first5=N. R. |author5-link=Nolan R. Walborn |last6=Gamen |first6=R. C. |last7=Arias |first7=J. I. |last8=Alfaro |first8=E. J. |year=2014 |doi=10.1088/0067-0049/211/1/10|arxiv = 1312.6222 |s2cid=118847528 }}

}}

{{Starbox astrometry

| radial_v = −34.6

| prop_mo_ra = -6.918

| prop_mo_dec = 2.764

| parallax = 0.4450

| p_error = 0.0203

| parallax_footnote = {{Cite Gaia EDR3|5350357519345171200}}

| dist_ly =

| dist_pc = {{val|1,970|180|150|fmt=commas}}{{cite journal|arxiv=1912.10125|doi=10.1093/mnras/stz3614|title=Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes|year=2020|last1=Crowther|first1=Paul A.|last2=Rate|first2=Gemma|journal=Monthly Notices of the Royal Astronomical Society|volume=493|issue=1|pages=1512–1529|doi-access=free |bibcode=2020MNRAS.493.1512R|s2cid=209444955}}

| absmag_bol =

| absmag_v = –6.98

}}

{{Starbox orbit

| reference=

| period_unitless=207.85 days

| eccentricity=0.50

| inclination=

| axis_unitless={{solar radius|156}}

| k1=44

}}

{{Starbox detail

| component1 = WR

| mass = 98

| radius = 20.24

| luminosity_bolometric = 2,400,000

| temperature = 50,100{{cite journal|arxiv=1904.04687|last1=Sota|first1=A.|title=The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters|last2=Maíz Apellániz|first2=J.|last3=Morrell|first3=N. I.|author-link3=Nidia Morrell|last4=Barbá|first4=R. H.|last5=Walborn|first5=N. R.|last6=Gamen|first6=R. C.|last7=Arias|first7=J. I.|last8=Alfaro|first8=E. J.|last9=Oskinova|first9=L. M.|journal=Astronomy & Astrophysics|year=2019|volume=A57|page=625|doi=10.1051/0004-6361/201834850|bibcode=2019A&A...625A..57H|s2cid=104292503}}

| age_myr =

}}

{{Starbox catalog

| names = HD 93162, 2MASS J10441038-5943111, WR 25, XMMU J104410.3-594311, CD−59°3282, PPM 339385, SAO 238408, Trumpler 16 177, GSC 08626-01989, UBV 9882, Hen 3-478

}}

{{Starbox reference

| Simbad = HD+93162

}}

WR 25 (HD 93162) is a binary star system in the turbulent star-forming region of the Carina Nebula, about 6,800 light-years from Earth. It contains a Wolf-Rayet star and a hot luminous companion and is a member of the Trumpler 16 cluster. The name comes from the Catalogue of Galactic Wolf–Rayet Stars.

Spectrum

WR 25 was recognised as a Wolf–Rayet star in the 19th century, because of its brightness and a spectrum dominated by broad emission lines.{{cite journal |bibcode=1894AstAp..13..448C |title=The Wolf-Rayet stars |journal=Astronomy and Astro-Physics |volume=13 |pages=448 |last1=Campbell |first1=W. W. |year=1894}} The spectrum contains lines of hydrogen and is intermediate between a classical WN (Wolf-Rayet) star and an O-type supergiant. This led to early reports that it was a binary, for example a WN7 star plus an O7 star.{{cite journal |bibcode=1968MNRAS.138..109S |title=A revised spectral classification system and a new catalogue for galactic Wolf-Rayet stars |journal=Monthly Notices of the Royal Astronomical Society |volume=138 |pages=109–121 |last1=Smith |first1=Lindsey F. |year=1968 |doi=10.1093/mnras/138.1.109|doi-access=free }} It has also been described as WN7 + abs{{cite journal |bibcode=1993SSRv...66..271C |title=Tailored analyses of 24 Galactic WN stars |journal=Space Science Reviews |volume=66 |issue=1–4 |pages=271–275 |last1=Crowther |first1=Paul A. |last2=Smith |first2=Linda J. |last3=Hillier |first3=D. John |year=1993 |doi=10.1007/BF00771076|s2cid=122574673 }} (meaning a Wolf-Rayet star with absorption lines of unknown origin) and WN6ha.{{cite journal |bibcode=1998A&A...334..845S |title=The relationship between the WR classification and stellar models. II. The WN stars without hydrogen |journal=Astronomy and Astrophysics |volume=334 |pages=845 |last1=Smith |first1=Lindsey F. |last2=Maeder |first2=A. |year=1998}} With the introduction of specific classifications for hot slash stars, WR 25 was assigned the spectral type O2.5If^*/WN6. This recognises the presence of nitrogen, the intrinsic weakness of many emission lines, and the presence of some helium and hydrogen absorption lines. The classification represents a fine gradation of weaker emission and stronger absorption than a WN6ha spectral type.{{cite journal |bibcode=2011MNRAS.416.1311C |arxiv=1105.4757 |title=Spectral classification of O2-3.5 If*/WN5-7 stars |journal=Monthly Notices of the Royal Astronomical Society |volume=416 |issue=2 |pages=1311 |last1=Crowther |first1=Paul A. |last2=Walborn |first2=Nolan R. |year=2011 |doi=10.1111/j.1365-2966.2011.19129.x|doi-access=free |s2cid=118455138 }} Any contribution to the spectrum from the companion cannot be clearly detected.

Properties

File:WR 25 and Tr16-244 region (cropped).jpg

The primary star of the WR 25 system is approximately 2.4 million times brighter than the Sun and illuminates the far southern end of the Trumpler 16 cluster. The model used to derive the stellar parameters is unsuitable for use in binary systems with the authors noting that the companion contributes more than 15% of the system luminosity, so the luminosity is highly uncertain. Earlier estimates based on measurements of the ionising flux produced values around 1.5 million times the sun, with correspondingly lower estimates for other physical data.{{Cite journal |doi=10.1046/j.1365-8711.1998.01400.x |title=Quantitative spectroscopy of Wolf--Rayet stars in HD 97950 and R136a -- the cores of giant H II regions |journal=Monthly Notices of the Royal Astronomical Society |volume=296 |issue=3 |pages=622–642 |year=1998 |last1=Crowther |first1=P. A. |last2=Dessart |first2=L. |bibcode=1998MNRAS.296..622C|doi-access=free }}

The companion is assumed to be a young hot massive star, similar to other known WR+O or WR+WR binaries. It has been reported as an O4 supergiant, but later measurements are still uncertain about the exact spectral type. Colliding stellar winds between two such hot luminous stars produce the hard X-rays{{Cite journal |doi=10.1088/0004-637X/788/1/84 |title=Phase-Resolvedxmm-Newtonandswiftobservations of Wr 25 |journal=The Astrophysical Journal |volume=788 |issue=1 |pages=84 |year=2014 |last1=Pandey |first1=J. C. |last2=Pandey |first2=S. B. |last3=Karmakar |first3=S. |bibcode=2014ApJ...788...84P |arxiv=1405.7137|s2cid=119197173 }} that led to suspicion about the binary status long before the 208-day orbital period was detected.{{Cite journal |doi=10.1051/0004-6361:20065618 |title=The first orbital solution for the massive colliding-wind binary HD 93162 (≡WR 25) |journal=Astronomy and Astrophysics |volume=460 |issue=3 |pages=777–782 |year=2006 |last1=Gamen |first1=R. |last2=Gosset |first2=E. |last3=Morrell |first3=N. |author-link3=Nidia Morrell |last4=Niemela |first4=V. |last5=Sana |first5=H. |last6=Nazé |first6=Y. |last7=Rauw |first7=G. |last8=Barbá |first8=R. |last9=Solivella |first9=G. |bibcode=2006A&A...460..777G |arxiv=astro-ph/0609454|s2cid=17677713 }}

Although very luminous, WR 25 is beyond naked-eye visibility due to heavy dust extinction of clouds in the nebula, and because much of the emitted radiation is in the ultraviolet. With an absolute magnitude of −6.98 at a distance of 1970 parsecs, it would be visible to the naked eye with a stellar magnitude of 4.49 if there were nothing in the way, rather than the actual 8.80. It has been observed in X-rays and infra-red.{{Cite journal |doi=10.1086/510184 |title=An X-Ray and Near-Infrared Study of Young Stars in the Carina Nebula |journal=The Astrophysical Journal |volume=656 |issue=1 |pages=462–473 |year=2007 |last1=Sanchawala |first1=K. |last2=Chen |first2=W. P. |last3=Lee |first3=H. T. |last4=Chu |first4=Y. H. |last5=Nakajima |first5=Y. |last6=Tamura |first6=M. |last7=Baba |first7=D. |last8=Sato |first8=S. |bibcode=2007ApJ...656..462S|citeseerx=10.1.1.667.3955 |s2cid=53352850 }}

WR 25 lies at the western limit of the Trumpler 16 star cluster, part of Carina OB1, one of the largest stellar associations in the Milky Way Galaxy.{{cite journal |bibcode=2011ApJS..194...12W |arxiv=1103.1126 |title=The Chandra Carina Complex Project View of Trumpler 16 |journal=The Astrophysical Journal Supplement |volume=194 |issue=1 |pages=12 |last1=Wolk |first1=Scott J. |last2=Broos |first2=Patrick S. |last3=Getman |first3=Konstantin V. |last4=Feigelson |first4=Eric D. |last5=Preibisch |first5=Thomas |last6=Townsley |first6=Leisa K. |last7=Wang |first7=Junfeng |last8=Stassun |first8=Keivan G. |last9=King |first9=Robert R.|last10=McCaughrean|first10=Mark J. |last11=Moffat |first11=Anthony F. J. |last12=Zinnecker |first12=Hans |year=2011 |doi=10.1088/0067-0049/194/1/12|s2cid=13951142 }} Because of its extreme luminosity it greatly affects its stellar environment, seen in the thin long arcs and filaments moving away from the star, including the Finger Nebula.{{cite book |bibcode=2012ASSL..384...25W |title=Eta Carinae and the Supernova Impostors |volume=384 |pages=25–42 |last1=Walborn |first1=Nolan R. |chapter=The Company Eta Carinae Keeps: Stellar and Interstellar Content of the Carina Nebula |year=2012 |doi=10.1007/978-1-4614-2275-4_2 |series=Astrophysics and Space Science Library |isbn=978-1-4614-2274-7}}

References

Category:Carina Nebula

Category:Wolf–Rayet stars

Category:Carina (constellation)

093162

Category:O-type supergiants

Category:Spectroscopic binaries

J10441038-5943111

Category:Durchmusterung objects

Category:TIC objects

WR 25

Spectrum

Properties

See also

References