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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 709686.0, MPI für Astronomie / Publikationen_mpia
The discovery of a very massive star in W49
Authors:Wu, S. -. W.; Bik, A.; Henning, T.; Pasquali, A.; Brandner, W.; Stolte, A.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:Astronomy and Astrophysics
Start Page:id. L13 (4 pp)
Audience:Not Specified
Abstract / Description:Context. Very massive stars (M> 100 M&sun;) are very rare objects, but have a strong influence on their environment. The formation of this kind of objects is of prime importance in star formation, but observationally still poorly constrained. <BR /> Aims: We report on the identification of a very massive star in the central cluster of the star-forming region W49. <BR /> Methods: We investigate near-infrared K-band spectroscopic observations of W49 from VLT/ISAAC together with JHK images obtained with NTT/SOFI and LBT/LUCI. We derive the spectral type of W49nr1, the brightest star in the dense core of the central cluster of W49. <BR /> Results: On the basis of its K-band spectrum, W49nr1 is classified as an O2-3.5If* star with a K-band absolute magnitude of -6.27 ± 0.10 mag. The effective temperature and bolometric correction are estimated from stars of similar spectral type. After comparison to the Geneva evolutionary models, we find an initial mass between 100 M&sun; and 180 M&sun;. Varying the extinction law results in a larger initial mass range of 90-250 M&sun;. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme IDs 67.C-0514 and 073.D-0837, and on data acquired using the Large Binocular Telescope (LBT).The reduced VLT FITS spectrum is only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> ( or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/L13">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/568/L13</A>
Free Keywords:stars: formation; stars: massive; supergiants; infrared: stars; techniques: spectroscopic; open clusters and associations: individual: W49
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-6361 %R 10.1051/0004-6361/201424154
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