Astronomy:HD 38029

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HD 38029
Location of HD 38029 (circled in red) near the Tarantula Nebula
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| Epoch J2000.0      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation Dorado
A
Right ascension  05h 36m 54.63s[1]
Declination −69° 11′ 38.1″[1]
Apparent magnitude (V) 12.18[2]
B
Right ascension  05h 36m 55.19s[3]
Declination −69° 11′ 37.6″[3]
Apparent magnitude (V) 11.56±0.01[4]
Characteristics
A
Evolutionary stage Wolf-Rayet[5]
Spectral type WC4 + O6–6.5III[5]
B
Evolutionary stage Hypergiant
Spectral type B1Ia+[6]
Astrometry
Radial velocity (Rv)265.2[6] km/s
Distance163,000[citation needed] ly
B
Proper motion (μ) RA: +1.878[3] mas/yr
Dec.: +0.661[3] mas/yr
Parallax (π)0.0360 ± 0.0178[3] mas
Distanceapprox. 90,000 ly
(approx. 30,000 pc){{{dist_ly2}}} ly
Details
B
Mass71[7] M☉
Radius74[8] R☉
Luminosity1,072,000[8] L☉
Surface gravity (log g)2.50[8] cgs
Temperature21,000[8] K
Rotational velocity (v sin i)48[7] km/s
Age2.9[8] Myr
Other designations
HD 38029, BAT99-85, Brey 67, CPD−69°429, TIC 277172073, 2MASS J05365516-6911376, AKARI-IRC-V1 J0536538-691140, WISE J053654.95-691137.9[9]
A: VFTS 2, SK −69 223[1]
B: VFTS 3, SK −69 224[10]
Database references
SIMBADAB
A
B

HD 38029 is a multiple star system located in the constellation of Dorado, in the Large Magellanic Cloud (LMC), one of the Milky Way's nearest satellite galaxies at a distance of approximately 163,000 light-years. The system lies near the prominent Tarantula Nebula star-forming region, a site of intense massive star formation. It consists of a carbon-sequence Wolf–Rayet (WR) primary star (HD 38029A) paired with a type O giant companion, along with a nearby luminous B supergiant (HD 38029B) that is likely part of the same small star cluster named BSDL 2586.[5][11] The combined magnitude of the three stars is 10.92.[12] HD 38029 is notable for its strong stellar winds and has been studied extensively for insights into massive star evolution, interstellar medium interactions, and diffuse interstellar bands (DIBs) in low-metallicity environments like the LMC.[13]

Charecterstics

HD 38029A is classified as a WC4 + O6–6.5 III binary, where the primary is a hot, helium and carbon-rich WR star exhibiting broad emission lines from its intense stellar winds, and the secondary is an O-type giant.[5] Earlier observations classified the WR component as WC5.[14] The WR star's spectrum shows prominent carbon lines (e.g., CIV, CIII) indicative of the carbon sequence (WC subtype), marking it as an evolved massive star (initial mass likely >25 solar masses) in a pre-supernova phase with high mass-loss rates. The system's radial velocity is approximately +265 km/s, consistent with LMC membership.[9]

The nearby HD 38029B is a B1 Ia+ hyper/supergiant with broad Balmer absorption lines potentially distorted by DIBs along the line of sight, located about 2.8 arcseconds (~0.8 parsecs at LMC distance) from HD 38029A.[5] The combined visual magnitude of the system is 11.55, with moderate reddening E(B−V) ≈ 0.32 due to LMC interstellar dust.[15] The WR winds drive an expanding interstellar bubble, contributing to feedback in the 30 Doradus region, analogous to structures in the Milky Way's Orion Nebula.[15]

Observation

HD 38029 has been observed with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) under program GO-12581, yielding far-ultraviolet spectra (G130M/1327 + G160M/1577/1589/1600) on 24 October 2012 to probe wind lines (e.g., SiIV λλ1393, 1402) and interstellar features.[16] These data support studies of massive star winds in low-metallicity settings and DIB properties in the LMC.[13] It is also part of the ULLYSES (Ultraviolet Legacy Library of Young Stars as Essential Standards) survey, providing archival UV data for evolutionary models.[15]

Ground-based spectroscopy from the VFTS has revealed broad Balmer wings in the B supergiant component, offering tests for atmospheric models distorted by foreground DIBs.[5]

References

  1. ↑ 1.0 1.1 1.2 "HD 38029A". https://simbad.cds.unistra.fr/mobile/object.html?object_name=HD%2038029A. 
  2. ↑ Neugent, Kathryn F.; Massey, Philip; Morrell, Nidia (2018). "A Modern Search for Wolf-Rayet Stars in the Magellanic Clouds. IV. A Final Census". The Astrophysical Journal 863 (2): 181. doi:10.3847/1538-4357/aad17d. Bibcode: 2018ApJ...863..181N. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. ↑ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (July 2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)" (in en). VizieR Online Data Catalog 1322: I/322A. Bibcode: 2012yCat.1322....0Z. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Walborn, Nolan R.; Sana, Hugues; Evans, Christopher J.; Taylor, William D.; Sabbi, Elena; Barbá, Rodolfo H.; Morrell, Nidia I.; Apellániz, Jesús Maíz et al. (2015-08-13). "Broad Balmer Wings in Ba Hyper/Supergiants Distorted by Diffuse Interstellar Bands: Five Examples in the 30 Doradus Region from the VLT-Flames Tarantula Survey". The Astrophysical Journal 809 (2): 109. doi:10.1088/0004-637X/809/2/109. ISSN 1538-4357. Bibcode: 2015ApJ...809..109W. 
  6. ↑ 6.0 6.1 Evans, C. J.; Kennedy, M. B.; Dufton, P. L.; Howarth, I. D.; Walborn, N. R.; Markova, N.; Clark, J. S.; De Mink, S. E. et al. (2015). "The VLT-FLAMES Tarantula Survey. XVIII. Classifications and radial velocities of the B-type stars". Astronomy and Astrophysics 574: A13. doi:10.1051/0004-6361/201424414. Bibcode: 2015A&A...574A..13E. 
  7. ↑ 7.0 7.1 McEvoy, C. M.; Dufton, P. L.; Evans, C. J.; Kalari, V. M.; Markova, N.; Simón-Díaz, S.; Vink, J. S.; Walborn, N. R. et al. (2015). "The VLT-FLAMES Tarantula Survey. XIX. B-type supergiants: Atmospheric parameters and nitrogen abundances to investigate the role of binarity and the width of the main sequence". Astronomy and Astrophysics 575: A70. doi:10.1051/0004-6361/201425202. Bibcode: 2015A&A...575A..70M. 
  8. ↑ 8.0 8.1 8.2 8.3 8.4 Schneider, F. R. N. et al. (2018). "An excess of massive stars in the local 30 Doradus starburst". Science 359 (6371): 69–71. doi:10.1126/science.aan0106. PMID 29302009. Bibcode: 2018Sci...359...69S. 
  9. ↑ 9.0 9.1 "HD 38029". https://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+38029. 
  10. ↑ "HD 38029B". https://simbad.cds.unistra.fr/mobile/object.html?object_name=HD%2038029B. 
  11. ↑ "BSDL 2586". https://simbad.cds.unistra.fr/mobile/object.html?object_name=BSDL%202586. 
  12. ↑ Lasker, Barry M.; Lattanzi, Mario G.; McLean, Brian J.; Bucciarelli, Beatrice; Drimmel, Ronald; Garcia, Jorge; Greene, Gretchen; Guglielmetti, Fabrizia et al. (2008). "The Second-Generation Guide Star Catalog: Description and Properties". The Astronomical Journal 136 (2): 735. doi:10.1088/0004-6256/136/2/735. Bibcode: 2008AJ....136..735L. 
  13. ↑ 13.0 13.1 Cox, N. L. J.; Cordiner, M. A.; Cami, J.; Foing, B. H.; Sarre, P. J.; Kaper, L.; Ehrenfreund, P. (March 2006). "The Large Magellanic Cloud: diffuse interstellar bands, atomic lines and the local environmental conditions". Astronomy & Astrophysics 447 (3): 991–1009. doi:10.1051/0004-6361:20053367. ISSN 0004-6361. 
  14. ↑ Morel, M. (1988). "LMC Wolf-rayet stars in the HD and HDE catalogues : A brief census". Bulletin d'Information du Centre de Donnees Stellaires 35: 31. Bibcode: 1988BICDS..35...31M. 
  15. ↑ 15.0 15.1 15.2 "ULLYSES LMC Targets". https://ullyses.stsci.edu/ullyses-targets-lmc.html. 
  16. ↑ Shepard, Katherine; Gies, Douglas R.; Lester, Kathryn V.; Wang, Luqian; Guo, Zhao; Kaper, Lex; De Koter, Alex; Sana, Hugues (2020-01-10). "HST/COS Spectra of the Wind Lines of VFTS 102 and 285". The Astrophysical Journal 888 (2): 82. doi:10.3847/1538-4357/ab5a82. ISSN 0004-637X. 



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