Trumpler 27
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]
| Trumpler 27 | |
|---|---|
| Observation data (J2000 epoch) | |
| Right ascension | 17h 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 designations | C 1732-334[1] |
| Associations | |
| Constellation | Scorpius |
| See also: Open cluster, List of open clusters | |
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]
| 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 | -10.1 | WN8/WC7 | |
| Trumpler 27-102 | 5,980 | -6.8 | -7 | G0Ia | |
| Trumpler 27-27 | 37,200 | -6.9 | -10.5 | 81 | O8III((f)) |
| Trumpler 27-23 | 27,500 | -7.5 | -10.2 | 64 | B0.5I |
| Trumpler 27-2 | 28,800 | -6.5 | -9.4 | 42 | B0Ia |
| Trumpler 27-46 | 11,200 | -8.7 | -9.3 | 35 | B8I |
| Trumpler 27-104 | 35,700 | -5.1 | -8.6 | 32 | O8.5III |
| Trumpler 27-43 | 11,200 | -8.2 | -8.9 | 29 | B8I |
| Trumpler 27-14 | 28,800 | -5.7 | -8.5 | 27 | B0Ib |
| Trumpler 27-16 | 27,500 | -5.7 | -8.5 | 26 | B0.5Ia |
| Trumpler 27-1a | 36,600 | -3.8 | -7.4 | 23 | |
| Trumpler 27-103 | 26,300 | -5.4 | -7.9 | 21 | B1I |
References
- ^ a b c d e "Cl Trumpler 27". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-03-31.
- ^ a b 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.
- ^ 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.
- ^ a b c 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.
- ^ a b 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.
- ^ 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.
- ^ a b c 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.
- ^ "HD 159378". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-03-31.
- ^ 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.