MWC 349
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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| Constellation | Cygnus |
| Right ascension | 20h 32m 45.5s |
| Declination | +40° 39′ 36.6″ |
| Apparent magnitude (V) | 10.45 |
| Characteristics | |
| Evolutionary stage | B[e] star[1] |
| Spectral type | Bpe |
| Astrometry | |
| Proper motion (μ) | RA: 35.5 mas/yr Dec.: -15.8 mas/yr |
| Distance | 4,560[2] ly (1400[2] pc) |
| Absolute magnitude (MV) | -6.7/-7.3[2] |
| Details | |
| Mass | 25 M☉ |
| Luminosity (bolometric) | 400,000/630,000[2] L☉ |
| Other designations | |
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MWC 349, V1478 Cyg, IRAS 20310+4029, 2MASS J20324553+4039366
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| Database references | |
| SIMBAD | data |
MWC 349 is a double (likely, triple) star system in the constellation Cygnus.
Features
MWC 349 is a Be type star, where the B is the spectral type and the e denotes emission. The central star MWC 349A interacts only weakly with its partner MWC 349B about 2.4 arcsec away.
While this particular star possesses a number of unusual features, a recent study suggests that it may not be a Herbig Be star at all, but rather a Luminous Blue Variable (LBV) with an absolute magnitude ranging between -6.7 and -7.3, along with a poorly understood bolometric luminosity. With a range of luminosity between 400,000-630,000 times that of our Sun, the star is surrounded by a circumstellar disk and a bipolar nebula, with a diameter of up to 5 parsecs, much like those found around other Luminous Blue Variable or candidates for that type of star.[2]
MWC 349 is surrounded by a protoplanetary disk of material that is being evaporated by the radiation pressure of the central star and has the third component of the system (if it exists), orbiting at a distance of 12-13 AU from the primary with a period of 9 years.[2] Emission lines of this star are those of the disk of material, not the star itself.
This is a variable star with the designation V1478 Cyg. MWC 349A is also one of the few Be type stars with a strong radio emission. It is also the only known example of a hydrogen recombination line maser in space. It is also the only firmly identified high-gain natural laser in the infrared recombination of hydrogen. [3]
MWC 349 may be a runaway star ejected from the nearby, massive Cygnus OB2 association. The mass of the main component of the system, MWC 349A, is assumed to have been when the star was born 40 times the mass of the Sun, but stellar evolution left it with just 20-25 solar masses, destabilizing the system and causing MWC 349B to puff out its chromosphere.[2]
References
- Near-infrared interferometric images of the solar system sized disk surrounding the Herbig Ae/Be star MWC 349A
Danchi W.C., Tuthill P.G. and Monnier J.D. 2001, Astrophysical Journal Letters.,
- "Discovery of a parsec-scale bipolar nebula around MWC349A", Gvaramadze & Menton, A&A 541, A7 (2012)
External links
- http://www.physics.usyd.edu.au/~gekko/mwc349.html
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