W40 IRS 1A South

W40 IRS 1A South
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 18h 31m 27.827s[1]
Declination −2° 5′ 22.86″[1]
Apparent magnitude (V) 15
Characteristics
Evolutionary stage O-type main-sequence star
Spectral type O9.5[2]
Astrometry
Distance436[3] pc
Absolute magnitude (MV)-4.25
Details
Radius7.71[2] R☉
Luminosity52,500 L☉
Temperature31,500[4] K
Other designations
(W40 IRS 1A:) CXOW40 J183127.84-020523.5, 2MASS J18312782-0205228
Database references
SIMBAD(IRS 1a) data

W40 IRS 1A South is a young O-type star in the H II region, Westerhout 40, one of the closest O type stars to the Sun at just over 1,400 light years away. It is the only known O-type star in W40 and is responsible for most of W40's ionisation, and its stellar wind has carved out a 4 pc wide bubble around it, which can be seen in wide field mid-IR images.[2] W40 IRS 1A South is separated from its northern counterpart, W40 IRS 1A North, which is a heavily reddened Herbig Be star, by approximately 2".

  1. ^ a b Cite error: The named reference 2mass was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference shuping was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference ortizleon was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference schneider was invoked but never defined (see the help page).