HD 259431
Location of HD 259431 (circled) near the bluish IC 447 nebulosity. NGC 2264 is below (west) and the Rosette Nebula on the right (south). Credit: ESO/S. Guisard | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Monoceros |
Right ascension | 06h 33m 05.19061s[1] |
Declination | +10° 19′ 19.9869″[1] |
Apparent magnitude (V) | 8.73[2] |
Characteristics | |
Spectral type | B6e[2] |
U−B color index | −0.540[3] |
B−V color index | 0.286[3] |
Astrometry | |
Radial velocity (Rv) | 19.00[4] km/s |
Proper motion (μ) | RA: -2.37[1] mas/yr Dec.: -2.72[1] mas/yr |
Parallax (π) | 5.78 ± 1.26 mas[1] |
Distance | approx. 600 ly (approx. 170 pc) |
Details | |
Mass | 6.6[5] M☉ |
Radius | 6.63[5] R☉ |
Temperature | 14,125[5] K |
Rotational velocity (v sin i) | 90[6] km/s |
Age | 0.32[5] Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 259431 (MWC 147 or V700 Monocerotis) is a young stellar object in the constellation of Monoceros.
Location
![](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Close-up_on_MWC_147.jpg/240px-Close-up_on_MWC_147.jpg)
HD 259431 lies in the northern portion of Monoceros, between Orion and Canis Minor, along with the spectacular Rosette Nebula and NGC 2264 region. It is half a degree from the faint IC 447 reflection nebula.
HD 259431 is seen against NGC 2247, a small reflection nebula and star-forming region. It has been considered to be the illuminating source for the nebula, although it is uncertain if they are at the same distance. The Hipparcos annual parallax gives a distance of 170 parsecs while NGC 2247 is thought to be at about 800 parsecs, although both distances are somewhat uncertain.[7] Many of its properties have been calculated assuming a distance of 800 parsecs, which means they are also highly uncertain.[2]
Properties
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/The_Growing-up_of_a_Star_-_the_disc_around_MWC_147_%28Annotated%29.jpg/220px-The_Growing-up_of_a_Star_-_the_disc_around_MWC_147_%28Annotated%29.jpg)
HD 259431 is classed as a Herbig Haro Be star and has been instrumental in helping astronomers understand the formation of stars.[5] A large star, with a large surrounding dust cloud,[6] MWC 147 has given astronomers a clear picture of the mechanics of the accretion processes that form stars.[8]
Star MWC 147 was observed in the near and mid-infrared. The near-infrared studies showed dust matter at a temperature of several thousand kelvins in the innermost regions of the protoplanetary disk. In the mid-IR were lower temperatures. These observations showed that the disk around the star disk extends over 100 AU.
The resulting research model assumes that the star increasing in mass at a rate 7×10−6 solar masses per year, or the equivalent of about two Earth masses per year. MWC has a mass of 6.6 M☉ and is younger than 500 000 years. This means that the life of this star is expected to be only about 35 million years.[citation needed]
The star is found in the night sky at RA 06 h 33 m 05.19 and Dec 10° 19' 19.9869". It has a temperature of 14 125 K and spectral type of B6ep. It is also known as 2MJ06330519 + 1019199, HD 259431, HIP 31235 and SAO 95823.
References
- ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
- ^ a b c Hernández, Jesús; Calvet, Nuria; Briceño, César; Hartmann, Lee; Berlind, Perry (2004). "Spectral Analysis and Classification of Herbig Ae/Be Stars". The Astronomical Journal. 127 (3): 1682. Bibcode:2004AJ....127.1682H. doi:10.1086/381908.
- ^ a b Kilkenny, D.; Whittet, D. C. B.; Davies, J. K.; Evans, A.; Bode, M. F.; Robson, E. I.; Banfield, R. M. (1985). "Optical and infrared photometry of southern early-type shell stars and pre-main-sequence variables". In its South African Astronomical Observatory Circular No. 9 p 55-86 (SEE N86-18271 08-89). 9. Bibcode:1985SAAOC...9...55K.
- ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
- ^ a b c d e Kraus, Stefan; Preibisch, Thomas; Ohnaka, Keiichi (2008). "Detection of an Inner Gaseous Component in a Herbig Be Star Accretion Disk: Near- and Mid-Infrared Spectrointerferometry and Radiative Transfer modeling of MWC 147". The Astrophysical Journal. 676: 490–508. arXiv:0711.4988. Bibcode:2008ApJ...676..490K. doi:10.1086/527427.
- ^ a b Bagnoli, T.; Van Lieshout, R.; Waters, L. B. F. M.; Van Der Plas, G.; Acke, B.; Van Winckel, H.; Raskin, G.; Meerburg, P. D. (2010). "An Inner Gaseous Disk Around the Herbig Be Star MWC 147". The Astrophysical Journal Letters. 724: L5. arXiv:1010.1414. Bibcode:2010ApJ...724L...5B. doi:10.1088/2041-8205/724/1/L5.
- ^ Lee, Chien-De; Chen, Wen-Ping; Liu, Sheng-Yuan (2016). "Evolutionary status of isolated B[e] stars". Astronomy & Astrophysics. 592: A130. arXiv:astro-ph/0512534. Bibcode:2016A&A...592A.130L. doi:10.1051/0004-6361/201628332.
- ^ "The Region Around MWC 147". European Space Agency. Retrieved 2016-12-24.