Trumpler 27
Observation data (J2000 epoch)
Right ascension17h 36m 20s[1]
Declination−33° 31.0′[1]
Apparent magnitude (V)6.7[1]
Apparent dimensions (V)6′ × 6′[1]
Physical characteristics
True nature is unknown[2]
Other designationsC 1732-334[1]
Associations
ConstellationScorpius

Trumpler 27 is a possible open cluster in the southern constellation Scorpius. If it exists, it is a few thousand light-years away from the Sun, with estimates ranging from 3,900 light-years (1,210 kiloparsecs)[3] to 6,800 light-years (2,100 kiloparsecs)[4] The name refers to Robert Julius Trumpler's catalog of open clusters, published in 1930.[5]

It was originally thought to be young open cluster in the outer edge of the Sagittarius Arm, still surrounded by interstellar matter.[5] The light from the stars is heavily extinguished and reddened by intervening interstellar dust.[4] The light coming from the stars is also significantly polarized.[6] However, a close study in 2012 could not confirm whether the stars truly form a cluster, or if they are a close alignment of bright stars.[2]

Several member stars have been studied in closer detail. Star #1 of Trumpler 27 is CD−33°12241, a red supergiant star with a spectral type of M0Ia. Stars #28 and #105 are Wolf-Rayet stars.[4][7] Star #27, a blue giant star with a spectral type of O8III((f)), may be one of the most luminous stars known, with a bolometric magnitude of −10.5.[7] Star #102 is known as V925 Scorpii or HD 159378,[8] and is a rare yellow supergiant star.[9]

Prominent stars[7]
Star name Temperature
(K)		 Absolute
magnitude		 Bolometric
magnitude		 Mass
(M☉)		 Spectral type
Trumpler 27-1 3,790 -8.57 -8.78 5.86 M0Ia
Trumpler 27-28 (WR 95) 44,000 -5.25 -8.3 10.7 WC9d
Trumpler 27-105 (WR 98)40,000-6.62-10.1WN8/WC7
Trumpler 27-1025,980-6.8-7G0Ia
Trumpler 27-2737,200-6.9-10.581O8III((f))
Trumpler 27-2327,500-7.5-10.264B0.5I
Trumpler 27-228,800-6.5-9.442B0Ia
Trumpler 27-4611,200-8.7-9.335B8I
Trumpler 27-10435,700-5.1-8.632O8.5III
Trumpler 27-4311,200-8.2-8.929B8I
Trumpler 27-1428,800-5.7-8.527B0Ib
Trumpler 27-1627,500-5.7-8.526B0.5Ia
Trumpler 27-1a36,600-3.8-7.423
Trumpler 27-10326,300-5.4-7.921B1I

See also

References

  1. 1 2 3 4 5 "Cl Trumpler 27". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-03-31.
  2. 1 2 Perren, G.; Vázquez, R. A.; Carraro, G. (2012). "Photometric distances to young stars in the inner Galactic disk. II. The region towards the open cluster Trumpler 27 at L = 355°". Astronomy and Astrophysics. 548: A125. arXiv:1209.3273. Bibcode:2012A&A...548A.125P. doi:10.1051/0004-6361/201219653. S2CID 62888409.
  3. ↑ Morales, Esteban F. E.; Wyrowski, Friedrich; Schuller, Frederic; Menten, Karl M. (2013). "Stellar clusters in the inner Galaxy and their correlation with cold dust emission". Astronomy and Astrophysics. 560: A76. arXiv:1310.2612. Bibcode:2013A&A...560A..76M. doi:10.1051/0004-6361/201321626. S2CID 118422539.
  4. 1 2 3 Moffat, A. F. J.; Fitzgerald, M. P.; Jackson, P. D. (1977). "Trumpler 27: A heavily reddened young open cluster with blue and red supergiants". The Astrophysical Journal. 215: 106. Bibcode:1977ApJ...215..106M. doi:10.1086/155338.
  5. 1 2 The, P. S.; Stokes, N. (1970). "A study of the southern open clusters : TR 27, TR 28, NGC 6416, NGC 6425". Astronomy and Astrophysics. 5: 298. Bibcode:1970A&A.....5..298T.
  6. ↑ Feinstein, Carlos; Baume, Gustavo; Vazquez, Ruben; Niemela, Virpi; Cerruti, Miguel Angel (2000). "The Highly Polarized Open Cluster Trumpler 27". The Astronomical Journal. 120 (4): 1906. arXiv:astro-ph/0007093. Bibcode:2000AJ....120.1906F. doi:10.1086/301562. S2CID 18701893.
  7. 1 2 3 Massey, P.; Degioia-Eastwood, K.; Waterhouse, E. (2001). "The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs. II. Results from 12 Galactic Clusters and OB Associations". The Astronomical Journal. 121 (2): 1050–1070. arXiv:astro-ph/0010654. Bibcode:2001AJ....121.1050M. doi:10.1086/318769. S2CID 53345173.
  8. ↑ "HD 159378". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-03-31.
  9. ↑ Bakker, R.; The, P. S. (1983). "An investigation of the heavily reddened young open cluster TR 27 on the Walraven photometric system". Astronomy and Astrophysics Supplement Series. 52: 27. Bibcode:1983A&AS...52...27B.
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