HD 152248: Evidence for a colliding wind interaction

Sana, H.; Rauw, Grégor; Gosset, Éric

doi:10.1051/0004-6361:20010221

Cited by 53 publications

(79 citation statements)

References 28 publications

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“…We calculated the geometrical center of the massive MS members with masses greater than about 5 M (V ≈ 11 mag) and adopted this as the center of NGC 6231. The adopted center of NGC 6231 is α J2000 = 16 h 54 m 11. s 7, δ J2000 = −41 • 50 20 , which is approximately equidistance from HD 152248 (O7.5III+O7III(f), Sana et al 2001); HD 152249 (O9Ib(f), Sana et al 2008) and HD 152270 (WC7+O6V, Hill et al 2000).…”

Section: Surface Density Profiles and The Radius Of Ngc 6231mentioning

confidence: 88%

The Initial Mass Function and the Surface Density Profile of NGC 6231

Sung

Sana²,

Bessell

2013

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We have performed new wide-field photometry of the young open cluster NGC 6231 to study the shape of the initial mass function (IMF) and mass segregation. We also investigated the reddening law toward NGC 6231 from optical to mid-infrared color excess ratios, and found that the total-to-selective extinction ratio is R V = 3.2, which is very close to the normal value. But many early-type stars in the cluster center show large color excess ratios. We derived the surface density profiles of four member groups, and found that they reach the surface density of field stars at about 10 , regardless of stellar mass. The IMF of NGC 6231 is derived for the mass range 0.8-45 M . The slope of the IMF of NGC 6231 (Γ = −1.1 ± 0.1) is slightly shallower than the canonical value, but the difference is marginal. In addition, the mass function varies systematically, and is a strong function of radius-it is very shallow at the center, and very steep at the outer ring suggesting the cluster is mass segregated. We confirm the mass segregation for the massive stars (m 8 M ) by a minimum spanning tree analysis. Using a Monte Carlo method, we estimate the total mass of NGC 6231 to be about 2.6 (±0.6) × 10 3 M . We constrain the age of NGC 6231 by comparison with evolutionary isochrones. The age of the low-mass stars ranges from 1 to 7 Myr with a slight peak at 3 Myr. However, the age of the high-mass stars depends on the adopted models and is 3.5 ± 0.5 Myr from the non-rotating or moderately rotating models of Brott et al. as well as the non-rotating models of Ekström et al. But the age is 4.0-7.0 Myr if the rotating models of Ekström et al. are adopted. This latter age is in excellent agreement with the timescale of ejection of the high-mass runaway star HD 153919 from NGC 6231, albeit the younger age cannot be entirely excluded.

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Section: Surface Density Profiles and The Radius Of Ngc 6231mentioning

confidence: 88%

The Initial Mass Function and the Surface Density Profile of NGC 6231

Sung

Sana²,

Bessell

2013

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“…Sana et al 2001). Various physical effects can induce a S-S signature: gaseous streams in the systems, ellipsoidal variations, surface streams, and changes in the local surface temperature due to, e.g., mutual illumination or heating from a wind-wind collision (e.g., Bagnuolo et al 1999;Linder et al 2007).…”

Section: H Sana and C J Evansmentioning

confidence: 99%

The multiplicity of massive stars

Sana

Evans

2010

Proc. IAU

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Abstract. Binaries are excellent astrophysical laboratories that provide us with direct measurements of fundamental stellar parameters. Compared to single isolated stars, multiplicity induces new processes, offering the opportunity to confront our understanding of a broad range of physics under the extreme conditions found in, and close to, astrophysical objects.In this contribution, we will discuss the parameter space occupied by massive binaries, and the observational means to investigate it. We will review the multiplicity fraction of OB stars within each regime, and in different astrophysical environments. In particular we will compare the O star spectroscopic binary fraction in nearby open clusters and we will show that the current data are adequately described by an homogeneous fraction of f ≈ 0.44.We will also summarize our current understanding of the observed parameter distributions of O + OB spectroscopic binaries. We will show that the period distribution is overabundant in short period binaries and that it can be described by a bi-modalÖpik law with a break point around P ≈ 10 d. The distribution of the mass-ratios shows no indication for a twin population of equal mass binaries and seems rather uniform in the range 0.2 q = M 2 /M1 1.0.

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“…We note however, that the available light curve solution of HD 152248 (Mayer et al 2001) does not support this idea. The present-day configuration of HD 152248 may have been affected by a past RLOF episode instead (Sana et al 2001). On the other hand, as stated previously the inclusion of rotation in the single star evolutionary models may in fact reduce the discrepancy between the observed and theoretical masses.…”

Section: Observational Evidence For Mass Exchange In Evolved Massive mentioning

confidence: 73%

“…In some cases, the comparison of the properties of their components with evolutionary tracks for single massive stars yields inconsistent results. For instance, in the case of HD 152248 (O7.5 III(f) + O7 III(f)) both stars appear overluminous for their masses (Sana et al 2001) and the evolutionary masses needed to account for the observed luminosity are ∼ 30% larger than the observed masses. Penny et al (1996) argued that this behaviour is an indication of ongoing Roche lobe overflow (RLOF).…”

Section: Observational Evidence For Mass Exchange In Evolved Massive mentioning

confidence: 99%

Massive binaries and colliding winds

Rauw

2004

EAS Publications Series

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Abstract. In this contribution, I review recent results from observational investigations of early-type binaries of spectral types O and WolfRayet. These studies aim at an accurate determination of fundamental parameters such as masses and radii of the most massive stars. In addition, multi-wavelength analyses of wind collisions in massive binaries provide constraints on the properties of stellar winds of massive stars and shock physics of cosmic plasmas.

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HD 152248: Evidence for a colliding wind interaction

Cited by 53 publications

References 28 publications

The Initial Mass Function and the Surface Density Profile of NGC 6231

The Initial Mass Function and the Surface Density Profile of NGC 6231

The multiplicity of massive stars

Massive binaries and colliding winds

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