BD+43 3654
BD+43 3654 is a massive luminous blue supergiant runaway star in the constellation Cygnus.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h 33m 36.079s[1] |
| Declination | +43° 59′ 07.38″[1] |
| Apparent magnitude (V) | 10.06[2] |
| Characteristics | |
| Spectral type | O4If[3] |
| Apparent magnitude (B) | 11.245[1] |
| Apparent magnitude (J) | 6.636[1] |
| Apparent magnitude (H) | 6.198[1] |
| Apparent magnitude (K) | 5.973[1] |
| Astrometry | |
| Proper motion (μ) | RA: 0.5 ± 1.3[2] mas/yr Dec.: 2.0 ± 1.3[2] mas/yr |
| Parallax (π) | 0.6057 ± 0.0304 mas[4] |
| Distance | 5,400 ± 300 ly (1,650 ± 80 pc) |
| Absolute magnitude (MV) | −6.27[1] |
| Details | |
| Mass | 64.6[1] M☉ |
| Radius | 18.8 R☉ |
| Luminosity (bolometric) | 850,000[5] L☉ |
| Temperature | 40,422[1] K |
| Age | 2.0[1] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Features
BD+43 3654 has a spectral type of O4If with a mass around 65 times larger than the Sun, likely 850,000 times brighter, and very young, with an age that has been estimated to be around 2 million years. Its distance to the Solar System has been estimated to be 1.45 kiloparsecs (4,700 light-years) and it is moving at high speed through the interstellar medium, creating a bow shock.[3]
Origin
Studies of the trajectory and speed of BD+43 3654 relative to the other stars of the nearby, massive stellar association Cygnus OB2 suggest it is a runaway star, making it one of the most massive runaway stars known in the Milky Way (along with the O-type supergiants Lambda Cephei and Zeta Puppis).[3] Initially it was suggested a supernova explosion of a former binary system companion star caused the high velocity of BD+43 3654.[3]
Later research shows that a supernova ejection would not produce such a high space velocity. Given that BD+43 3654 appears to be younger than most stars in Cygnus OB2, an alternative scenario has been proposed in which BD+43 3654 is a massive blue straggler born in an encounter between two former double stars in the core of Cygnus OB2. In this setting, two stars of each binary would collide and merge forming a larger, more massive star (BD+43 3654), that would be ejected from the stellar association along with two other stars. These additional stars would end by exploding as supernovae to leave behind two pulsars. B2020+28 and B2021+51 are identified as these pulsars, as their dynamics indicate they were expelled from Cygnus OB2.[6] A derivative consequence of the latter scenario is that the brightest and most massive stars of Cygnus OB2 would be blue stragglers too.
Another theory is that runaways of this mass and velocity can be produced by an encounter between a massive single star and a close binary system. Such an encounter is expected to send the binary system in the opposite direction to the single star, and no such massive binary has been found corresponding to BD+43 3654.[7]
See also
References
- Comerón, F.; Pasquali, A. (2012). "New members of the massive stellar population in Cygnus". Astronomy & Astrophysics. 543: A101. Bibcode:2012A&A...543A.101C. doi:10.1051/0004-6361/201219022. ISSN 0004-6361.
- Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862.
- Comerón, F.; Pasquali, A. (2007). "A very massive runaway star from Cygnus OB2". Astronomy & Astrophysics. 467 (1): L23–L27. arXiv:0704.0676. Bibcode:2007A&A...467L..23C. doi:10.1051/0004-6361:20077304. S2CID 16843959.
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Hillier, D. J.; Schaerer, D.; Martins, F. (2005). "A new calibration of stellar parameters of Galactic O stars". Astronomy & Astrophysics. 436 (3): 1049–1065. arXiv:astro-ph/0503346. Bibcode:2005A&A...436.1049M. doi:10.1051/0004-6361:20042386. S2CID 39162419.
- Gvaramadze, V. V.; Bomans, D. J. (2008). "BD+43 3654 - a blue straggler?". Astronomy & Astrophysics. 485 (3): L29–L32. arXiv:0805.3893. Bibcode:2008A&A...485L..29G. doi:10.1051/0004-6361:200809860. S2CID 18755032.
- Gvaramadze, Vasilii V.; Gualandris, Alessia (2011). "Very massive runaway stars from three-body encounters". Monthly Notices of the Royal Astronomical Society. 410 (1): 304–312. arXiv:1007.5057. Bibcode:2011MNRAS.410..304G. doi:10.1111/j.1365-2966.2010.17446.x. S2CID 123481910.