γ2 Velorum: orbital solution and fundamental parameter determination with SUSI

By J. North, P. Tuthill, W. Tango, J. Davis. 2007

258 citations recorded by the source corpus.

The first complete orbital solution for the double-lined spectroscopic binary system γ 2 Velorum, obtained from measurements with the Sydney University Stellar Interferometer (SUSI), is presented. This system contains the closest example of a Wolf-Rayet star and the promise of full characterization of the basic properties of this exotic high-mass system has subjected it to intense study as an archetype for its class. In combination with the latest radial-velocity results, our orbital solution produces a distance of 336 +8 -7 pc, significantly more distant than the Hipparcos estimation. The ability to fully specify the orbital parameters has enabled us to significantly reduce uncertainties and our result is consistent with the Very Large Telescope Interferometer (VLTI) observational point, but not with their derived distance. Our new distance, which is an order of magnitude more precise than prior work, demands critical reassessment of all distance-dependent fundamental parameters of this important system. In particular, membership of the Vela OB2 association has been re-established, and the age and distance are also in good accord with the population of young stars reported by Pozzo et al. We determine the 0-star primary component parameters to be M v (O) = -5.63 ± 0.10mag, R(O) = 17 ± 2 R ⊙ and M(0) = 28.5 ± 1.1 M ⊙ . These values are consistent with calibrations found in the literature if a luminosity class of II-III is adopted. The parameters of the Wolf-Rayet (WR) component are M v (WR) = -4.33 ±0.17 mag and M(WR) = 9.0 ±0.6M ⊙ .

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b2845fcc41f7e09ba3cc0c13cd389dc450b41534

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In Astronomy and Astrophysics

1. L. Hartmann
2. N. Calvet
3. J. Muzerolle
4. K. Luhman
5. R. Gutermuth
6. B. Mason
7. W. Hartkopf
8. Jesús Hernández

In Instrumentation

1. L. Hartmann
2. E. Stanway
3. J. Eldridge
4. N. Calvet
5. B. Mason
6. W. Hartkopf
7. J. Muzerolle
8. J. Helsel

Citations in the corpus

• A Spitzer View of Protoplanetary Disks in the γ Velorum Cluster (2008, methodology): “We assume the corrected Hipparcos distance of 350 pc, which is in agreement within 1.5σ from the distance calculated by Millour et al. (2007) and North et al. (2007) and a reference age of 5 Myr.”
• VEGA: Visible spEctroGraph and polArimeter for the CHARA array: principle and performance (2009, background): “SUSI (Davis et al. 2007) and the VLTI (Glindemann et al. 2004) have already carried out pioneering works in this field (North et al. 2007; Millour et al. 2007).”
• THE HIGH ANGULAR RESOLUTION MULTIPLICITY OF MASSIVE STARS (2008, background): “The symbols have the same meaning as in Figure 3. is a spectroscopic binary that has been resolved by optical long baseline interferometry; North et al. 2007).”
• Binary Population and Spectral Synthesis Version 2.1: Construction, Observational Verification, and New Results (2017, methodology): “…paper, we supplement this sample with data on three additional (non-eclipsing) binary systems: VV Cephei (Wright 1977; Bauer, Stencel, & Neff 1991; Hack et al. 1992; Bennett et al. 2004; Hagen Bauer, Gull, & Bennett 2008; Bennett 2010), WR20a (Rauw et al. 2005), andγ -Velorum (North et al. 2007).”
• The stellar association around Gamma Velorum and its relationship with Vela OB2 (2008, methodology): “North et al. (2007) use their interferometric distance to estimate an absolute V magnitude of −5.63 ± 0.10 for the O-star component of γ2 Vel, and that it has a mass and age of 28.5 ± 1.1M⊙ and 3.5 ± 0.4 Myr using the solarmetallicity evolutionary models of Meynet et al. (1994).”