LBV phenomenon and binarity: The environment of HR Car

Abstract

Luminous blue variable stars (LBVs) are of great interest in massive-star evolution as they experience very high mass-loss episodes within short periods of time. HR Car is a famous member of this class in the Galaxy. It has a large circumstellar nebula and has also been confirmed as being in a binary system. One means of gaining information about the evolutionary status and physical nature of LBVs is studying their environments. We investigated the stellar content within ~100 pc of HR Car and also its circumstellar nebula. Very Large Telescope (VLT) Multi Unit Spectroscopic Explorer (MUSE) observations of a 2'x2' region around the star highlight the incompleteness of stellar classification for stars with magnitudes of V > 13 mag. Eight B0 to B9 stars have been identified which may lie in close spatial vicinity to HR Car. For a region with a radius of r =1.2 degree (~100 pc at a distance of 4.8 kpc) around HR Car, existing catalogs list several late O-type and early B-type stars, but only one early O-type star. Given the relatively low stellar and nebular masses in the HR Car system, no early O-type stars and only a few late O-type stars would be expected in association with HR Car. Instead, HR Car's location in a point vector diagram suggests that HR Car is not isolated, but is part of a moving group with a population of B-type stars in a spiral arm, and it has not received a strong kick from a supernova explosion of a companion star or a merger event. Potential binary evolution pathways for the HR Car system cannot be fully explored because of the unknown nature of the companion star. Furthermore, the MUSE observations reveal the presence of a fast outflow and "bullets" that have been ejected at intervals of about 400 years. These features may have been caused by recurrent mass transfer in the system.

arXiv comment11 pages, 5 figures, to be published in A&A

References in corpus (43)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Correcting for the Effects of Interstellar Extinction
• The SIMBAD astronomical database
• Binary interaction dominates the evolution of massive stars
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Astrophysics Source Code Library
• The MUSE second-generation VLT instrument
• Pulsational Pair-Instability Supernovae
• The Data Processing Pipeline for the MUSE Instrument
• SkyMapper Southern Survey: Second Data Release (DR2)
• The relation between the most-massive star and its parental star cluster mass
• Luminous Blue Variables are Antisocial: Their Isolation Implies that they are Kicked Mass Gainers in Binary Evolution
• Stellar envelope inflation near the Eddington limit. Implications for the radii of Wolf-Rayet stars and luminous blue variables
• Massive main sequence stars evolving at the Eddington limit
• Luminous Blue Variables and superluminous supernovae from binary mergers
• The evolution of massive stars and their spectra I. A non-rotating 60 Msun star from the zero-age main sequence to the pre-supernova stage
• Masses and Luminosities of O and B - type stars and red super giants
• Grids of stellar models with rotation IV. Models from 1.7 to 120 Msun at a metallicity Z = 0.0004
• OB associations and their origins
• Periastron Passage Triggering of the 19th Century Eruptions of Eta Carinae
• On the Social Traits of Luminous Blue Variables
• Bona-fide, strong-variable galactic Luminous Blue Variable stars are fast rotators: detection of a high rotational velocity in HR Carinae
• Was the nineteenth century giant eruption of Eta Carinae a merger event in a triple system?
• The shape of $\eta$ Carinae and LBV Nebulae
• Simulating the formation of $\eta$ Carinae's surrounding nebula through unstable triple evolution and stellar merger-induced eruption
• On the Gaia DR2 distances for Galactic Luminous Blue Variables
• Multiplicity of Galactic Luminous Blue Variable stars
• Modelling Luminous-Blue-Variable Isolation
• Shedding Light on the Isolation of Luminous Blue Variables
• Super-Eddington stellar winds: unifying radiative-enthalpy vs. flux-driven models
• The Villafranca catalog of Galactic OB groups: I. Systems with O2-O3.5 stars
• The deep OB star population in Carina from the VST Photometric H$\alpha$ Survey (VPHAS+)
• X-ray Emission from Eta Carinae near Periastron in 2009 I: A Two State Solution
• Classifying Single Stars and Spectroscopic Binaries Using Optical Stellar Templates
• The isolation of Luminous Blue Variables: On subdividing the sample
• The isolation of Luminous Blue Variables resembles aging B-type supergiants, not the most massive unevolved stars
• VLT/MUSE discovers a jet from the evolved B[e] star MWC 137
• Tight LMC massive star clusters R 127 and R 128
• Exploring the multifaceted circumstellar environment of the Luminous Blue Variable HR Carinae
• The LBV HR Car has a partner: Discovery of a companion with the VLTI
• Detection of new O-type stars in the obscured stellar cluster Tr 16-SE in the Carina Nebula with KMOS

Cited by in corpus (3)

• Search for LBVs in the Local Volume galaxies: study of two stars in NGC 1156
• Luminous Blue Variables
• Integral field spectroscopy supports atmospheric optics to reveal the finite outer scale of the turbulence