Wolf--Rayet binaries in the Magellanic Clouds and implications for massive-star evolution -- I. Small Magellanic Cloud

Foellmi, C.; Moffat, A. F. J.; Guerrero, M. A.

doi:10.1046/j.1365-8711.2003.06052.x

Cited by 97 publications

(153 citation statements)

References 46 publications

Supporting

Mentioning

143

Contrasting

Order By: Relevance

“…4690 A In addition, along with general expectations, WR 4 is a periodic photometric variable (Foellmi et al 2003;days) and P p 6.55 not an obvious binary. This period is then likely related to rotation.…”

mentioning

confidence: 69%

“…We targeted three presumably single (Foellmi et al 2003) early-type WN stars in the SMC: SMC WR 1 (WN3ha), WR 2 (WN5ha), and WR 4 (WN6h), thus forming a representative sample of the small SMC W-R population (12 known Population I W-R stars, most of them early-type WN stars; Massey et al 2003). We monitored the stars in continuous, ∼1 hr 40 minute long loops for two consecutive nights in 2006 August (between HJD 2,453,974.538 and HJD 2,453,975.877), alternating among the three targets: WR 4-WR 2-WR 1, etc.…”

Section: Observationsmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopy of SMC Wolf-Rayet Stars Suggests that Wind Clumping Does Not Depend on Ambient Metallicity

Марченко¹,

Foellmi²,

Moffat³

et al. 2007

ApJ

Self Cite

View full text Add to dashboard Cite

The mass-loss rates of hot, massive, luminous stars are considered a decisive parameter in shaping the evolutionary tracks of such stars and influencing the interstellar medium on galactic scales. The small-scale structures (clumps) that are omnipresent in such winds may reduce empirical estimates of mass-loss rates by an evolutionarily significant factor of ≥3. So far, there has been no direct observational evidence that wind clumping may persist at the same level in environments with a low ambient metallicity, where the wind-driving opacity is reduced. Here we report the results of time-resolved spectroscopy of three presumably single Population I Wolf-Rayet stars in the Small Magellanic Cloud, where the ambient metallicity is ∼ Z , . We detect numerous small-scale 1 5 emission peaks moving outward in the accelerating parts of the stellar winds. The general properties of the moving features, such as their velocity dispersions, emissivities, and average accelerations, closely match the corresponding characteristics of small-scale inhomogeneities in the winds of Galactic Wolf-Rayet stars.

show abstract

mentioning

confidence: 69%

Section: Observationsmentioning

confidence: 99%

Spectroscopy of SMC Wolf-Rayet Stars Suggests that Wind Clumping Does Not Depend on Ambient Metallicity

Марченко¹,

Foellmi²,

Moffat³

et al. 2007

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…8), which contains the only WO star, SK 188, known in the SMC 6 . The relative position of the bow shock, the 6 Actualy, SK 188 is a binary system composed of WO4 and O V stars (Foellmi et al 2003a). star, and the association on the sky are consistent with the possibility that [M2002] SMC 83962 was ejected from NGC 602c.…”

Section: Search For Bow Shocks In the Smcmentioning

confidence: 99%

Massive runaway stars in the Small Magellanic Cloud

Gvaramadze

Kroupa

Pflamm-Altenburg

2010

A&A

View full text Add to dashboard Cite

Using archival Spitzer Space Telescope data, we identified for the first time a dozen runaway OB stars in the Small Magellanic Cloud (SMC) through the detection of their bow shocks. The geometry of detected bow shocks allows us to infer the direction of motion of the associated stars and to determine their possible parent clusters and associations. One of the identified runaway stars, AzV 471, was already known as a high-velocity star on the basis of its high peculiar radial velocity, which is offset by 40 km s −1 from the local systemic velocity. We discuss implications of our findings for the problem of the origin of field OB stars. Several of the bow shockproducing stars are found in the confines of associations, suggesting that these may be "alien" stars contributing to the age spread observed for some young stellar systems. We also report the discovery of a kidney-shaped nebula attached to the early WN-type star SMC-WR3 (AzV 60a). We interpreted this nebula as an interstellar structure created owing to the interaction between the stellar wind and the ambient interstellar medium.

show abstract

“…Because of the presence of the He  nebula, this star, like BAT99-2, was classified as WN1 by Pakull (1991). More recent studies of the star undertaken by Niemela et al (2002) and by Foellmi et al (2003a) led to a re-classification of the star as WN2+O6I(f) and WN4+O6I(f), respectively. Figure 2 shows an Hα image of the whole field.…”

Section: Star Smc Ab7 and Its Associated Nebula Smc N76mentioning

confidence: 99%

“…Total exposure times (in s) for each object, in each filter and for each grism. Spectral types are taken from Foellmi et al (2003a and2003b), Bartzakos et al (2001) and Niemela et al (2002 We thus decided to investigate the case of the three high excitation nebulae around WR stars in the MCs. The nebula around BAT99-2 was already analysed in Nazé et al (2003, hereafter Paper I) and we discuss here the two remaining cases.…”

Section: Introductionmentioning

confidence: 99%

WR bubbles and He II emission

Nazé

Rauw

Manfroid

et al. 2003

A&A

View full text Add to dashboard Cite

Abstract. We present the very first high quality images of the He  λ4686 emission in three high excitation nebulae of the Magellanic Clouds. A fourth high excitation nebula, situated around the WR star BAT99-2, was analysed in a previous letter. Using VLT FORS data, we investigate the morphology of the ring nebulae around the early-type WN stars BAT99-49 & AB7. We derive the total He  fluxes for each object and compare them with the most recent theoretical WR models. Whilst the ionization of the nebula around BAT99-49 can be explained by a WN star of temperature 90-100 kK, we find that the He  emission measure of the nebula associated with AB7 requires an He + ionizing flux larger than predicted for the hottest WN model available. Using Hα, [O ] and He  λ5876 images along with long-slit spectroscopy, we investigate the physical properties of these ring nebulae and find only moderate chemical enrichment.We also surveyed seven other LMC WR stars but we failed to detect any He  emission. This holds also true for BAT99-9 which had been proposed to excite an He  nebula. Four of these surveyed stars are surrounded by a ring nebula, and we use the FORS data to derive their chemical composition: the nebula around BAT99-11 shows a N/O ratio and an oxygen abundance slightly lower than the LMC values, while the nebula around BAT99-134 presents moderate chemical enrichment similar to the one seen near BAT99-2, 49 and AB7. Comparing the WR stars of the LMC, BAT99-2 and 49 appear unique since similar stars do not reveal high excitation features. The third high excitation nebula presented in this paper, N44C, does not harbor stars hotter than mid-O main sequence stars. It was suggested to be a fossil X-ray nebula ionized by the transient LMC X-5. Our observations of N44C reveal no substantial changes in the excitation compared to previous results reported in the literature. Therefore, we conclude that either the recombination timescale of the X-ray nebula has been underestimated or that the excitation of the nebula is produced by another, yet unknown, mechanism.

show abstract

Wolf--Rayet binaries in the Magellanic Clouds and implications for massive-star evolution -- I. Small Magellanic Cloud

Cited by 97 publications

References 46 publications

Spectroscopy of SMC Wolf-Rayet Stars Suggests that Wind Clumping Does Not Depend on Ambient Metallicity

Spectroscopy of SMC Wolf-Rayet Stars Suggests that Wind Clumping Does Not Depend on Ambient Metallicity

Massive runaway stars in the Small Magellanic Cloud

WR bubbles and He II emission

Contact Info

Product

Resources

About