An HST Study of OB Associations and Star Clusters in M101

Abstract

view Abstract Citations (36) References (54) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An HST Study of OB Associations and Star Clusters in M101 Bresolin, Fabio ; Kennicutt, Robert C., Jr. ; Stetson, Peter B. Abstract The massive stellar content, the OB associations and the star clusters in an HST field in M101 = NGC 5457 are investigated. A clustering algorithm yields 79 putative associations. Their size distribution is similar to that found in the Magellanic Clouds, M31, and M33, with an average size around 90 pc. The V luminosity function for the stars contained within the associations has a slope dlogN/dV = 0.60+/-0.05, while an average reddening E(B - V) = 0.21 mag is measured. The stellar content is further discussed by means of color-magnitude and color-color diagrams. Ages are estimated using theoretical isochrones, and range between 3 and 14 Myr (+/-2 Myr). We find a suggestion that the upper mass limit of the IMF for stars in OB associations in M101 may be quite high, contrary to some theoretical expectations that the mass limit should be lower in a high metallicity environment. Forty-one star cluster candidates and two H II region core clusters are identified in the M101 field, and their integrated photometric properties are compared with the cluster system of the Large Magellanic Cloud (LMC) and M33. Most of the M101 clusters probably belong to the class of young, populous star clusters such as are found in the LMC. Red clusters are rare in this field. In the Appendix the objective finding algorithm is applied to the brightest stars in the LMC. Publication: The Astronomical Journal Pub Date: September 1996 DOI: 10.1086/118073 arXiv: arXiv:astro-ph/9606050 Bibcode: 1996AJ....112.1009B Keywords: STARS: FORMATION; GALAXIES: EVOLUTION; Astrophysics E-Print: 25 pages + 6tables Figures also available via anonymous ftp at ftp://pollux.as.arizona.edu/pub/fabio/ full text sources arXiv | ADS | data products SIMBAD (8) NED (6) MAST (1) ESA (1)