Modelling the optical spectrum of Romano’s star★

Maryeva, O. V.; Abolmasov, P.

doi:10.1111/j.1365-2966.2011.19802.x

Cited by 18 publications

(27 citation statements)

References 41 publications

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“…However, several of our sample stars are not far from this region, while some known LBVs like WRAY 15-751 are close to it, but outside. The bona fide LBV V532, known as Romano's star, even appears as WN8 during its hot phase Maryeva & Abolmasov 2012). We therefore cannot rule out that at least a subsample of our analyzed stars, especially those located at a very similar position as known LBVs, such as #38 or #27, could represent LBVs during their quiet stage.…”

Section: Late Wn Stars As Lbv Candidatesmentioning

confidence: 93%

“…The empirical Humphreys-Davidson limit is also indicated. The parameters of the comparison stars are taken from Nazé et al (2012) with the exception of Romano's Star (V532, Clark et al 2012;Maryeva & Abolmasov 2012) and the Peony star (Barniske et al 2008). The locations of LBVs in different stages are connected by dashed lines.…”

Section: Late Wn Stars As Lbv Candidatesmentioning

confidence: 99%

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The Wolf-Rayet stars in M 31

Sander

Todt

Hainich

et al. 2014

A&A

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Context. Comprehensive studies of Wolf-Rayet stars were performed in the past for the Galactic and the LMC population. The results revealed significant differences, but also unexpected similarities between the WR populations of these different galaxies. Analyzing the WR stars in M 31 will extend our understanding of these objects in different galactic environments. Aims. The present study aims at the late-type WN stars in M 31. The stellar and wind parameters will tell about the formation of WR stars in other galaxies with different metallicity and star formation histories. The obtained parameters will provide constraints to the evolution of massive stars in the environment of M 31. Methods. We used the latest version of the Potsdam Wolf-Rayet model atmosphere code to analyze the stars via fitting optical spectra and photometric data. To account for the relatively low temperatures of the late WN10 and WN11 subtypes, our WN models have been extended into this temperature regime. Results. Stellar and atmospheric parameters are derived for all known late-type WN stars in M 31 with available spectra. All of these stars still have hydrogen in their outer envelopes, some of them up to 50% by mass. The stars are located on the cool side of the zero age main sequence in the Hertzsprung-Russell diagram, while their luminosities range from 10 5 to 10 6 L . It is remarkable that no star exceeds 10 6 L . Conclusions. If formed via single-star evolution, the late-type WN stars in M 31 stem from an initial mass range between 20 and 60 M . From the very late-type WN9-11 stars, only one star is located in the S Doradus instability strip. We do not find any late-type WN stars with the high luminosities known in the Milky Way.

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Section: Late Wn Stars As Lbv Candidatesmentioning

confidence: 93%

Section: Late Wn Stars As Lbv Candidatesmentioning

confidence: 99%

The Wolf-Rayet stars in M 31

Sander

Todt

Hainich

et al. 2014

A&A

View full text Add to dashboard Cite

show abstract

“…Bearing this important caveat in mind, changes in bolometric luminoity are not unprecendented in bona fide LBVs, having been observed in e.g. AFGL 2298 and Romano's star (Clark et al 2009b;Maryeva & Abolmasov 2012). Moreover, while S18 has not been observed to transition to the cool hypergiant phase that characterises many LBV excursions, the range of spectroscopic variability it exhibits (WN9h⇔P Cygni-type LBV) mirrors the behaviour of Romano's Star (Maryeva & Abolmasov 2012).…”

Section: S18 As a Lbvmentioning

confidence: 97%

The supergiant B[e] star LHA 115-S 18 – binary and/or luminous blue variable?

Clark

Bartlett

Coe

et al. 2013

A&A

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Context. The mechanism by which supergiant (sg)B[e] stars support cool, dense dusty discs/tori and their physical relationship with other evolved, massive stars such as luminous blue variables is uncertain. Aims. In order to investigate both issues we have analysed the long term behaviour of the canonical sgB[e] star LHA 115-S 18. Methods. We employed the OGLE II-IV lightcurve to search for (a-)periodic variability and supplemented these data with new and historic spectroscopy. Results. In contrast to historical expectations for sgB[e] stars, S18 is both photometrically and spectroscopically highly variable. The lightcurve is characterised by rapid aperiodic "flaring" throughout the 16 years of observations. Changes in the high excitation emission line component of the spectrum imply evolution in the stellar temperature -as expected for luminous blue variablesalthough somewhat surprisingly, spectroscopic and photometric variability appears not to be correlated. Characterised by emission in low excitation metallic species, the cool circumstellar torus appears largely unaffected by this behaviour. Finally, in conjunction with intense, highly variable He ii emission, X-ray emission implies the presence of an unseen binary companion.Conclusions. S18 provides observational support for the putative physical association of (a subset of) sgB[e] stars and luminous blue variables. Given the nature of the circumstellar environment of S18 and that luminous blue variables have been suggested as supernovae progenitors, it is tempting to draw a parallel to the progenitors of SN1987A and SN2009ip. Moreover the likely binary nature of S18 strengthens the possibility that the dusty discs/tori that characterise sgB[e] stars are the result of binary-driven mass-loss; consequently such stars may provide a window on the short lived phase of mass-transfer in massive compact binaries.

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“… References are (1) Crowther et al (1999), (2) Hamann et al (2006), (3) Herald et al (2001) and (4) Maryeva & Abolmasov (2012). …”

Section: Modelling Resultsmentioning

confidence: 99%

“…Hence, we pay special attention to a comparison between these two objects. Similar modelling for V532 was published in a separate paper (Maryeva & Abolmasov 2012). This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 93%

Spectral study of the late nitrogen-sequence Wolf-Rayet star FSZ35 in M33

Maryeva

Abolmasov

2012

Monthly Notices of the Royal Astronomical Society

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We study and analyse the low‐resolution spectra of the unusual late nitrogen‐sequence Wolf–Rayet (WN) star FSZ35 in M33. We classify the object as a hydrogen‐rich WN8 star. Using the radiative transfer code cmfgen, we determine the physical parameters of this object and we compare these to the parameters of other WN8 stars, including the luminous blue variable V532 (also known as Romano’s star) during the minimum of its brightness. Unlike V532, the object is fairly stable, both spectrally and photometrically, which can be attributed to its more advanced evolutionary stage or lower luminosity. FSZ35 is shown to possess a compact nebula that produces a faint but detectable [O iii] emission.

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Modelling the optical spectrum of Romano’s star★

Cited by 18 publications

References 41 publications

The Wolf-Rayet stars in M 31

The Wolf-Rayet stars in M 31

The supergiant B[e] star LHA 115-S 18 – binary and/or luminous blue variable?

Spectral study of the late nitrogen-sequence Wolf-Rayet star FSZ35 in M33

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