An O2 IfWN6 star caught in the act in a compact H ii region in the starburst cluster NGC 3603

作者：Roman Lopes A^*

来源：Monthly Notices of the Royal Astronomical Society, 2013, 433(1): 712-718.

DOI：10.1093/mnras/stt762

• stars: individual: WR20aa
• stars: individual: WR20c
• stars: Wolf-Rayet
• open clusters and associations: individual: Westerlund 2
• infrared: stars

In this paper, we report on the discovery of an O2 IfWN6 star probably still partially embedded in its parental cocoon in the starburst cluster NGC 3603. From the observed size of the associated compact H ii region, it has been possible to derive a probable dynamic age of no more than 600 000 yr. Using the computed visual extinction value A(V) similar to 6.0 +/- 0.2 mag, an absolute visual magnitude M-V = -5.7 mag has been obtained. For the assumed heliocentric distance of 7.6 kpc, this results in a bolometric luminosity of 8 x 10(5) L-circle dot. Also, from the V magnitude and the V - I colour of the new star, and from previous models for the massive star population of NGC 3603, we estimate the mass of the binary (O2 IfWN6 + O3 If) and the single star (O2 IfWN6). For the binary, we find that the initial masses of each component possibly exceed 80 and 40 M-circle dot, respectively, while for the single star the initial mass of MTT 58 is possibly in excess of 100 M-circle dot.

• 出版日期2013-7