The Quintuplet Cluster II. Analysis of the WN stars

Abstract

Based on $K$-band integral-field spectroscopy, we analyze four Wolf-Rayet stars of the nitrogen sequence (WN) found in the inner part of the Quintuplet cluster. All WN stars (WR102d, WR102i, WR102hb, and WR102ea) are of spectral subtype WN9h. One further star, LHO110, is included in the analysis which has been classified as Of/WN? previously but turns out to be most likely a WN9h star as well. The Potsdam Wolf-Rayet (PoWR) models for expanding atmospheres are used to derive the fundamental stellar and wind parameters. The stars turn out to be very luminous, $\log (L/L_{\odot })>6.0$, with relatively low stellar temperatures, $T_{\ast }\approx$ 25--35\,kK. Their stellar winds contain a significant fraction of hydrogen, up to $X_{\mathrm{H}}\sim 0.45$ (by mass). We discuss the position of the Galactic center WN stars in the Hertzsprung-Russell diagram and find that they form a distinct group. In this respect, the Quintuplet WN stars are similar to late-type WN stars found in the Arches cluster and elsewhere in the Galaxy. Comparison with stellar evolutionary models reveals that the Quintuplet WN stars should have been initially more massive than 60\,$M_{\odot }$. They are about 2.1 to 3.6\,Million years old, and might still be central hydrogen burning objects. The analysis of the spectral energy distributions of the program stars results in a mean extinction of $A_K=3.1\pm 0.5$\,mag ($A_V=27\pm 4$\,mag) towards the Quintuplet cluster.

arXiv comment9 pages, 7 figures, 4 tables, article published in A&A (with better layout)

References in corpus (28)

• Physical Properties of Wolf-Rayet Stars
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Stellar evolution with rotation X: Wolf-Rayet star populations at solar metallicity
• Massive Stars in the Quintuplet Cluster
• The Galactic WN stars: Spectral analyses with line-blanketed model atmospheres versus stellar evolution models with and without rotation
• Massive Stars in the Arches Cluster
• Bright OB stars in the Galaxy - III. Constraints on the radial stratification of the clumping factor in hot star winds from a combined Halpha, IR and radio analysis
• Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit
• A census of the Wolf-Rayet content in Westerlund 1 from near-infrared imaging and spectroscopy
• The most massive stars in the Arches cluster
• Stellar and wind properties of massive stars in the central parsec of the Galaxy
• Hydrodynamic model atmospheres for WR stars: Self-consistent modeling of a WC star wind
• Metallicity in the Galactic Center: The Quintuplet cluster
• Metallicity in the Galactic Center: The Arches cluster
• Evolution of X-ray emission from young massive star clusters
• On the role of the WNH phase in the evolution of very massive stars: Enabling the LBV instability with feedback
• The Interplay between Star Formation and the Nuclear Environment of our Galaxy: Deep X-ray Observations of the Galactic Center Arches and Quintuplet Clusters
• The chemical abundances in the Galactic Centre from the atmospheres of Red Supergiants
• Mid-infrared imaging and spectroscopy of the enigmatic cocoon stars in the Quintuplet Cluster
• Bona-fide, strong-variable galactic Luminous Blue Variable stars are fast rotators: detection of a high rotational velocity in HR Carinae
• 2 um Narrow-band Adaptive Optics Imaging in the Arches Cluster
• Pinwheels in the Quintuplet Cluster
• The Quintuplet Cluster I. A K-band spectral catalog of stellar sources
• High Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula: Evidence for Ejection
• Stellar Winds and Embedded Star Formation in the Galactic Center Quintuplet and Arches Clusters: Multifrequency Radio Observations
• A Second Luminous Blue Variable in the Quintuplet Cluster
• Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas
• Developments in physics of massive stars

Cited by in corpus (30)

• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• The Wolf-Rayet stars in the Large Magellanic Cloud: A comprehensive analysis of the WN class
• The ages of young star clusters, massive blue stragglers and the upper mass limit of stars: analysing age dependent stellar mass functions
• A comparison of evolutionary tracks for single Galactic massive stars
• The Galactic WC and WO stars: The impact of revised distances from Gaia DR2 and their role as massive black hole progenitors
• Wolf-Rayet stars in the Small Magellanic Cloud: I. Analysis of the single WN stars
• Early magnetic B-type stars: X-ray emission and wind properties
• Non-Thermal Insights on Mass and Energy Flows Through the Galactic Centre and into the Fermi Bubbles
• The Central 300 pc of the Galaxy probed by infrared spectra of H${}_3^{+}$ and CO: part I. Predominance of warm and diffuse gas and high H${}_2$ ionization rate
• Driving classical Wolf-Rayet winds: A Γ- and Z-dependent mass-loss
• Grids of stellar models with rotation VII: Models from 0.8 to 300 M${}_{\odot }$ at super-solar metallicity (Z = 0.020)
• The Quintuplet Cluster III. Hertzsprung-Russell diagram and cluster age
• Isolated massive stars in the Galactic center: The dynamic contribution from the Arches and Quintuplet star clusters
• An updated stellar census of the Quintuplet cluster
• A Multiwavelength Study of Evolved Massive Stars in the Galactic Center
• The orbital motion of the Quintuplet cluster - a common origin for the Arches and Quintuplet clusters?
• One of the most massive stars in the Galaxy may have formed in isolation
• Abell 48 - a rare WN-type central star of a planetary nebula
• Circumstellar discs in Galactic centre clusters: Disc-bearing B-type stars in the Quintuplet and Arches clusters
• The Wolf-Rayet stars in M31: I. Analysis of the late-type WN stars
• 2D kinematics of massive stars near the Galactic Center
• A Study of Wolf-Rayet stars Formed via Chemically Homogeneous Evolution
• Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center
• WR 120bb and WR 120bc: a pair of WN9h stars with possibly interacting circumstellar shells
• Analysis of the WN star WR 102c, its WR nebula, and the associated cluster of massive stars in the Sickle Nebula
• Massive stars in the young cluster VVV CL074
• Low-end mass function of the Quintuplet cluster
• Stellar Populations in the Galactic Center
• Near-Eddington mass loss of hydrogen-rich Wolf-Rayet stars
• Radio observations of massive stars in the Galactic centre: The Quintuplet cluster