Empirical properties of Very Massive Stars

Abstract

In this contribution we present the properties of the most massive stars known by the end of 2013. We start with a summary of historical claims for stars with masses in excess of several hundreds, even thousands of solar masses. We then describe how we determine masses for single stars. We focus on the estimates of luminosities and on the related uncertainties. We also highlight the limitations of evolutionary models used to convert luminosities into masses. The most luminous single stars in the Galaxy and the Magellanic Clouds are subsequently presented. The uncertainties on their mass determinations are described. Finally, we present binary stars. After recalling some basics of binary analysis, we present the most massive binary systems and the estimates of their dynamical masses.

arXiv comment34 pages, 8 figures - Chapter to appear in the book "Very Massive Stars in the Local Universe", Springer, (Ed. J.S. Vink)

References in corpus (53)

• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• A new calibration of stellar parameters of Galactic O stars
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• A Grid of NLTE Line-Blanketed Model Atmospheres of O-type Stars
• SINFONI in the Galactic Center: young stars and IR flares in the central light month
• The Formation of Massive Star Systems by Accretion
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• Forming the First Stars in the Universe: The Fragmentation of Primordial Gas
• Stellar evolution with rotation XI: Wolf-Rayet star populations at different metallicities
• Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity
• Atmospheric NLTE-Models for the Spectroscopic Analysis of Blue Stars with Winds. II. Line-Blanketed Models
• HST/NICMOS Observations of Massive Stellar Clusters Near the Galactic Center
• Protostellar Feedback Halts the Growth of the First Stars in the Universe
• The Discordance of Mass-Loss Estimates for Galactic O-Type Stars
• Interstellar Extinction Law toward the Galactic Center III: J, H, Ks bands in the 2MASS and the MKO systems, and 3.6, 4.5, 5.8, 8.0 micron in the Spitzer/IRAC system
• The maximum stellar mass, star-cluster formation and composite stellar populations
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• UBVJHK synthetic photometry of Galactic O stars
• An upper limit to the masses of stars
• Massive Stars in the Arches Cluster
• Low mass loss rates in O-type stars: Spectral signatures of dense clumps in the wind of two Galactic O4 stars
• Evidence for a fundamental stellar upper mass limit from clustered star formation
• Evolution and fate of very massive stars
• The mass-loss rates of red supergiants and the de Jager prescription
• The relation between the most-massive star and its parental star cluster mass
• The most massive stars in the Arches cluster
• The Eddington factor as the key to understand the winds of the most massive stars. Evidence for a Gamma-dependence of Wolf-Rayet type mass loss
• Discovery of an Extraordinarily Massive Cluster of Red Supergiants
• The VLT-FLAMES survey of massive stars: Wind properties and evolution of hot massive stars in the LMC
• Statistical Confirmation of a Stellar Upper Mass Limit
• The massive star initial mass function of the Arches cluster
• WR 20a is an Eclipsing Binary: Accurate Determination of Parameters for an Extremely Massive Wolf-Rayet System
• A comparison of evolutionary tracks for single Galactic massive stars
• Metallicity in the Galactic Center: The Quintuplet cluster
• Dynamical Masses of Young Star Clusters in NGC 4038/4039
• Mass Function of the Arches Cluster from Gemini Adaptive Optics Data
• Dynamical Mass Estimates for Two Luminous Star Clusters in Galactic Merger Remnants
• WR20a: a massive cornerstone binary system comprising two extreme early-type stars
• The VLT-FLAMES Tarantula Survey III: A very massive star in apparent isolation from the massive cluster R136
• Massive stars at low metallicity: Evolution and surface abundances of O dwarfs in the SMC
• The masses, and the mass discrepancy of O-type stars
• The very massive binary NGC3603-A1
• Star formation in 30 Doradus
• Nitrogen line spectroscopy in O-stars -- III. The earliest O-stars
• Mid-infrared imaging and spectroscopy of the enigmatic cocoon stars in the Quintuplet Cluster
• Photometric and Spectroscopic Studies of Massive Binaries in the Large Magellanic Cloud. I. Introduction and Orbits for Two Detached Systems: Evidence for a Mass Discrepancy?
• VLT/SINFONI time-resolved spectroscopy of the central, luminous, H-rich WN stars of R136
• Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas
• R144 revealed as a double-lined spectroscopic binary
• Massive open star clusters using the VVV survey II. Discovery of six clusters with Wolf-Rayet stars
• The two components of the evolved massive binary LZ Cep. Testing the effects of binarity on stellar evolution
• High-angular resolution observations of the Pistol Star

Cited by in corpus (11)

• Spectroscopic and physical parameters of Galactic O-type stars. III. Mass discrepancy and rotational mixing
• Possible pair-instability supernovae at solar metallicity from magnetic stellar progenitors
• Uncertainties in Galactic Chemical Evolution Models
• Very massive stars and Nitrogen emitting galaxies
• The most massive stars in very young star clusters with a limited mass: Evidence favours significant self-regulation in the star formation processes
• Very Massive Stars and Pair-Instability Supernovae: Mass-loss Framework for low Metallicity
• Spectroscopic evolution of very massive stars at Z = 1/2.5 Zsun
• The hydrogen clock to infer the upper stellar mass
• K I 7699 Å and related shell lines during the recent eclipse of $\epsilon$ Aurigae
• The VLT-FLAMES Tarantula Survey
• Evolutionary models for the Very Massive Stars in the R136 cluster of 30 Doradus in the Large Magellanic Cloud