Related papers: NGC 663 as a laboratory for massive star evolution

The compact association Cygnus OB2 is known to contain a large population of massive stars, but its total mass is currently a matter of debate. While recent surveys have uncovered large numbers of OB stars in the area around Cyg OB2,…

The very young open cluster NGC 6383 centered on the O-star binary HD 159176 is an interesting place for studying the impact of early-type stars with strong radiation fields and powerful winds on the formation processes of low-mass stars.…

The multiplicity properties of massive stars are one of the important outstanding issues in stellar evolution. Quantifying the binary statistics of all evolutionary phases is essential to paint a complete picture of how and when massive…

The blue compact dwarf galaxy NGC 5253 hosts a very young starburst containing twin nuclear star clusters, separated by a projected distance of 5 pc. One cluster (#5) coincides with the peak of the H-alpha emission and the other (#11) with…

Observations of massive stars in young open clusters (< ~8 Myr) have shown that a majority of them are in binary systems, most of which will interact during their life. Populations of massive stars older than ~20 Myr allow us to probe the…

Using high-resolution Hubble Space Telescope data, we reexamine the fundamental properties (ages, masses and extinction values) of the rich star cluster population in the dwarf starburst galaxy NGC 5253. The gain in resolution compared to…

The origin of initial rotation rates of stars, and how a star's surface rotational velocity changes during the evolution, either by internal angular momentum transport or due to interactions with a binary companion, remain open questions in…

Context. Stellar physical properties of star clusters are poorly known. Aims. Our goals are to perform a spectrophotometric study of the B star population in open clusters to derive accurate stellar parameters, search for the presence of…

The Milky Way's nuclear star cluster (NSC) is a unique laboratory to study the formation and evolution of dense stellar systems around a supermassive black hole. Previous work suggests that most stars in the NSC are old; however, the…

Models of stellar structure and evolution can be constrained using accurate measurements of the parameters of eclipsing binary members of open clusters. Multiple binary stars provide the means to tighten the constraints and, in turn, to…

We present observations of a massive star cluster near the nuclear region of the nearby starburst galaxy NGC 253. The peak of near-infrared emission, which is spatially separated by 4" from the kinematic center of the galaxy, is coincident…

We study the multiple populations of $\omega$ Cen by using the abundances of Fe, C, N, O, Mg, Al, Si, K, Ca, and Ce from the high-resolution, high signal-to-noise (S/N$>$70) spectra of 982 red giant stars observed by the SDSS-IV/APOGEE-2…

We present a detailed clustering analysis of the young stellar population across the star-forming ring galaxy NGC 6503, based on the deep HST photometry obtained with the Legacy ExtraGalactic UV Survey (LEGUS). We apply a contour-based map…

We obtained U_330 and B band images of the M31 nucleus using the High Resolution Camera of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST). The spatial resolution in the U_330-band, 0.03" FWHM, or 0.1 pc at M31, is…

Using observations obtained with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope (HST), we have studied the properties of the stellar populations in the central regions of 30 Dor, in the Large Magellanic Cloud. The…

The Perseus OB1 association hosts one of the most populous groupings of blue and red supergiants (Sgs) in the Galaxy. We discuss whether the massive O-type and blue/red Sg stars located in the Per OB1 region are members of the same…

The formation, properties, and evolution of massive stars remain subject to considerable uncertainty; impacting on fields as diverse as galactic feedback and the nature of the progenitors of both electromagnetic and gravitational wave…

We have analyzed two epochs of HST/WFPC2 observations of the young Galactic starburst cluster in NGC 3603 with the aim to study its internal dynamics and stellar population. Relative proper motions measured over 10.15 yrs of more than 800…

We have extracted PSF-fitted stellar photometry from near-ultraviolet, optical and near-infrared images, obtained with the Hubble Space Telescope, of the nearby (D ~ 5.5 Mpc) SBm galaxy NGC 1311. The ultraviolet and optical data reveal a…

An important question about Be stars is whether Be stars are born as Be stars or not. It is necessary to observe young clusters to answer this question. Observations of stars in NGC6611 and the star-formation region of Eagle Nebula have…