CPD−57° 2874

CPD−57° 2874 is a B[e] supergiant in the constellation Carina.[7] It is a rare star as it is hot but has dust which shows forbidden lines and IR emissions.[8] In 2007 the high spatial and spectral resolution of the star's circumstellar envelope was studied. This was the first time such a study was carried out on a class B[e] supergiant.[5][9]

CPD−57° 2874
Observation data
Epoch J2000      Equinox J2000
Constellation Carina
Right ascension  10h 15m 21.9711s[1]
Declination −57° 51′ 42.713″[1]
Apparent magnitude (V) +10.08[2]
Characteristics
Spectral type sgB1[e][2][3]
U−B color index +0.30[2]
B−V color index +1.65[2]
Variable type suspected[3][4]
Astrometry
Radial velocity (Rv)−54[5] km/s
Proper motion (μ) RA: −5.90[1] mas/yr
Dec.: 5.10[1] mas/yr
Distance3,440[5] pc
Absolute magnitude (MV)−7.7[5]
Details
Mass17.4 - 18.6[5] M☉
Radius60[2] R☉
Luminosity500,000[6] L☉
Temperature20,000[2] K
Rotational velocity (v sin i)36 ± 4[5] km/s
Other designations
CD–57° 3107, CPD–57° 2874, GSC 08608-00427, PPM 769178
Database references
SIMBADdata

Disc

CPD−57° 2874 is surrounded by a disc of expelled stellar material. The inner edge of the disc is 27.5 AU from the star and it is inclined at an angle of 46° to us. The particular alignment, temperature, and density of the disc combine to produce the forbidden spectral lines. The detached ring leads to speculation that the inner regions are cleared by an unseen binary companion.[5]

Variability

Photometry of CPD−57° 2874 suggests that it is variable with an amplitude of perhaps 0.2 magnitudes. It has not been formally classified as a variable star and the cause of the variations is unclear.[5]

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See also

References
  1. Hog, E.; Kuzmin, A.; Bastian, U.; Fabricius, C.; Kuimov, K.; Lindegren, L.; Makarov, V. V.; Roeser, S. (1998). "The TYCHO Reference Catalogue". Astronomy and Astrophysics. 335: L65. Bibcode:1998A&A...335L..65H.
  2. Domiciano De Souza, A.; Driebe, T.; Chesneau, O.; Hofmann, K.-H.; Kraus, S.; Miroshnichenko, A. S.; Ohnaka, K.; Petrov, R. G.; Preisbisch, T.; Stee, P.; Weigelt, G.; Lisi, F.; Malbet, F.; Richichi, A. (2007). "AMBER/VLTI and MIDI/VLTI spectro-interferometric observations of the B[e] supergiant CPD-57°2874. Size and geometry of the circumstellar envelope in the near- and mid-IR". Astronomy and Astrophysics. 464: 81. arXiv:astro-ph/0510735. Bibcode:2007A&A...464...81D. doi:10.1051/0004-6361:20054134.
  3. Domiciano De Souza, A.; Bendjoya, P.; Niccolini, G.; Chesneau, O.; Borges Fernandes, M.; Carciofi, A. C.; Spang, A.; Stee, P.; Driebe, T. (2011). "Fast ray-tracing algorithm for circumstellar structures (FRACS). II. Disc parameters of the B[e] supergiant CPD-57°,2874 from VLTI/MIDI data". Astronomy and Astrophysics. 525: A22. arXiv:1009.3422. Bibcode:2011A&A...525A..22D. doi:10.1051/0004-6361/201015194.
  4. Drilling, J. S. (1991). "UBV photometry of OB+ stars in the southern Milky Way". Astrophysical Journal Supplement Series. 76: 1033. Bibcode:1991ApJS...76.1033D. doi:10.1086/191588.
  5. Cidale, L. S.; et al. (2012). "Observational constraints for the circumstellar disk of the B[e] star CPD − 529243". Astronomy and Astrophysics. 548 (A72): 2. Bibcode:2012A&A...548A..72C. doi:10.1051/0004-6361/201220120.
  6. Kraus, M. (2009). "The pre- versus post-main sequence evolutionary phase of B[e] stars. Constraints from 13CO band emission". Astronomy and Astrophysics. 494 (1): 253. arXiv:0901.0714. Bibcode:2009A&A...494..253K. doi:10.1051/0004-6361:200811020.
  7. Fernandes, M. Borges (2010). "The Nature Of Stars With The B[e] Phenomenon Through Interferometric Eyes". Revista Mexicana de Astronomía y Astrofísica, Serie de Conferencias. 38: 98–99. Bibcode:2010RMxAC..38...98B.
  8. F. Malbet; et al. (2007). "In The Intimacy Of Stars With Amber At The VLTI". SF2A: 2. Bibcode:2007sf2a.conf...13M.
  9. International Astronomical Union. Symposium (2008). Massive Stars as Cosmic Engines (IAU S250). Cambridge University Press. p. 153. ISBN 9780521874724.
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