Westerlund 1 W237

Last updated
Westerlund 1 W237
Westerlund 1 - Hubble Space Telescope - Potw1710a.jpg
Red circle.svg
Westerlund 1 super star cluster (north is towards top left). The location of Wd 1-237 is circled.
Credit: ESO
Observation data
Epoch J2000       Equinox J2000
Constellation Ara [1]
Right ascension 16h 47m 03.1075s [2]
Declination −45° 52′ 18.957″ [2]
Apparent magnitude  (V)19.008 [3]
Characteristics
Evolutionary stage either a red supergiant or a foreground giant [4]
Spectral type M3Ia [5] or M6+ III [6]
Apparent magnitude  (B)22.8[ citation needed ]
Apparent magnitude  (R)13.634 [3]
Apparent magnitude  (G)11.259 [2]
Apparent magnitude  (J)5.075 [7]
Apparent magnitude  (H)3.01 [7]
Apparent magnitude  (K)2.18 [7]
Astrometry
Proper motion (μ)RA: -3.09±0.15 [2] mas/yr
Dec.: -4.12±0.12 [2] mas/yr
Parallax (π)0.3370±0.1235  mas [2]
Distance 3,000 [8] or 623 [9]   pc
Absolute magnitude  (MV)–6.96 [10]
Details
if a supergiant
Radius 1,241±70 [10]   R☉
Luminosity 219,000±26,000 [10]   L☉
Temperature 3,550 [10] - 3,605 [9]   K
Age 7.9 [10]   Myr
if a foreground giant
Radius 216 [9]   R☉
Luminosity1,000 [4] or 7,178 – 7,379 [9]   L☉
Temperature 3,605 [9]   K
Other designations
Westerlund 1 W237, Westerlund 1 BKS B, 2MASS J16470309-4552189, Gaia DR3 5940105904023386752
Database references
SIMBAD data

Westerlund 1 W237, also known as Wd 1-237 or Westerlund 1 BKS B, is a possible red supergiant (RSG) in the constellation of Ara. It is one out of four known red supergiants in the Westerlund 1 super star cluster. As a red supergiant, it would be one of the largest known stars and one of the most luminous of its type. [8]

Contents

Physical characteristics

Westerlund 1 W237 compared to the other 3 RSGs (Red Supergiants) in the Westerlund 1 star cluster. Comparison of Radii of RSGs located in the Westerlund 1 star cluster.png
Westerlund 1 W237 compared to the other 3 RSGs (Red Supergiants) in the Westerlund 1 star cluster.

Westerlund 1 W237 is classified as a luminous cool supergiant emitting most of its energy in the infrared spectrum. [11] It is surrounded by a radio nebula which is similar in mass to those of Westerlund 1-20 and Westerlund 1 W26, and moreover directly comparable to that of VY Canis Majoris. The elliptical structure of this nebula however indicates that it has been less affected by the cluster wind of Westerlund 1 (W20 and W26 have pronounced cometary shaped nebulae). The outflow velocity for the RSG wind is assumed to be around 30 km/s. The nebula itself seems to have a mass of 0.07 M☉ and a radius of about 0.11 parsecs. This results in a kinematic age around 3,600 years and a time averaged mass loss rate of 2×10−5  M☉ per year. [12]

The star occupies the upper right corner of the Hertzsprung-Russell diagram. With an effective temperature of 3,550 K and a bolometric luminosity of 219,000 L☉, the radius of Westerlund 1 W237 would be 1,241 times the solar radius (R☉), making it larger than the orbit of Jupiter. The initial mass of W237 has been calculated from its position relative to theoretical stellar evolutionary tracks to be around 28 M☉ or 32 M☉ for a non-rotating star. [10]

Distance

The distance of Westerlund 1 W237 is assumed to be around 8,500+2,000
−1,300  light years or 2,600+600
−400  parsecs [13] based on it being commonly thought of as a member of the Westerlund 1 star cluster (the elliptical shape of its nebula indicates that it might not be near the center of W1, while other RSGs like W20 and W26 are). [12] Another but older source suggests a similar distance of 3,000±500 parsecs. [8]

Westerlund's 1987 analysis assigned a spectral type of M6+ III to W1-237 and considered it to be a foreground giant with a luminosity only around 1,000 L☉. [4] Gaia Data Release 2 gives a parallax of 1.64±0.2608  mas for W237, implying a distance of 623+139
−96  pc and a luminosity of 7,178–7,379 L☉ with a corresponding radius of 216 R☉. [14] [9] In 2020, the parallax was revised to the much smaller value of 0.3370±0.1235 mas, corresponding to a distance of 2967±1087 pc (9670±3540 ly). [2]

See also

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 Bonanos, Alceste Z. (2007). "Variability of Young Massive Stars in the Galactic Super Star Cluster Westerlund 1". The Astronomical Journal. 133 (6): 2696–2708. arXiv: astro-ph/0702614 . Bibcode:2007AJ....133.2696B. doi:10.1086/518093. S2CID   119074868.
  4. 1 2 3 Westerlund, B. E. (1987). "Photometry and spectroscopy of stars in the region of a highly reddened cluster in ARA". Astronomy and Astrophysics. Supplement. 70 (3): 311–324. Bibcode:1987A&AS...70..311W. ISSN   0365-0138.
  5. ↑ Clark, J. S.; Ritchie, B. W.; Negueruela, I. (2010). "A serendipitous survey for variability amongst the massive stellar population of Westerlund 1". Astronomy and Astrophysics. 514: A87. arXiv: 1003.5107 . Bibcode:2010A&A...514A..87C. doi:10.1051/0004-6361/200913820. S2CID   14780809.
  6. ↑ Bonanos, Alceste Z. (2007). "Variability of Young Massive Stars in the Galactic Super Star Cluster Westerlund 1". The Astronomical Journal. 133 (6): 2696–2708. arXiv: astro-ph/0702614 . Bibcode:2007AJ....133.2696B. doi:10.1086/518093. S2CID   119074868.
  7. 1 2 3 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  8. 1 2 3 Fok, Thomas K. T.; Nakashima, Jun-Ichi; Yung, Bosco H. K.; Hsia, Chih-Hao; Deguchi, Shuji (2012). "Maser Observations of Westerlund 1 and Comprehensive Considerations on Maser Properties of Red Supergiants Associated with Massive Clusters". The Astrophysical Journal. 760 (1): 65. arXiv: 1209.6427 . Bibcode:2012ApJ...760...65F. doi:10.1088/0004-637X/760/1/65. S2CID   53393926.
  9. 1 2 3 4 5 6 Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv: 1905.03744 . Bibcode:2019AJ....158...20M. doi: 10.3847/1538-3881/ab1cbd . S2CID   148571616.
  10. 1 2 3 4 5 6 Arévalo, Aura (2019). The Red Supergiants in the Supermassive Stellar Cluster Westerlund 1 (Thesis). doi: 10.11606/D.14.2019.tde-12092018-161841 .
  11. ↑ "Cl* Westerlund 1 W 237". Simbad.
  12. 1 2 Dougherty, S. M.; Clark, J. S.; Negueruela, I.; Johnson, T.; Chapman, J. M. (2010-02-01). "Radio emission from the massive stars in the galactic super star cluster Westerlund 1". Astronomy & Astrophysics. 511: A58. arXiv: 0912.4165 . Bibcode:2010A&A...511A..58D. doi:10.1051/0004-6361/200913505. ISSN   0004-6361. S2CID   9792700.
  13. ↑ Aghakhanloo, Mojgan; Murphy, Jeremiah W.; Smith, Nathan; Parejko, John; Díaz-Rodríguez, Mariangelly; Drout, Maria R.; Groh, Jose H.; Guzman, Joseph; Stassun, Keivan G. (2020-02-21). "Inferring the parallax of Westerlund 1 from Gaia DR2". Monthly Notices of the Royal Astronomical Society. 492 (2): 2497–2509. arXiv: 1901.06582 . Bibcode:2020MNRAS.492.2497A. doi: 10.1093/mnras/stz3628 . ISSN   0035-8711. S2CID   119465620.
  14. ↑ Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Mantelet, G.; Andrae, R. (2018). "Estimating Distance from Parallaxes. IV. Distances to 1.33 Billion Stars in Gaia Data Release 2". The Astronomical Journal. 156 (2): 58. arXiv: 1804.10121 . Bibcode:2018AJ....156...58B. doi: 10.3847/1538-3881/aacb21 . S2CID   119289017.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.