A new survey of cool supergiants in the Magellanic Clouds

We study the spatial correlations between the H α emission and different types of massive stars in two local galaxies, the Large Magellanic Cloud (LMC) and Messier 33. We compare these to correlations derived for core-collapse supernovae (CCSNe) in the literature to connect CCSNe of different types with the initial masses of their progenitors and to test the validity of progenitor mass estimates which use the pixel statistics method. We obtain samples of evolved massive stars in both galaxies from catalogues with good spatial coverage and/or completeness, and combine them with coordinates of main-sequence stars in the LMC from the SIMBAD database. We calculate the spatial correlation of stars of different classes and spectral types with H α emission. We also investigate the effects of distance, noise and positional errors on the pixel statistics method. A higher correlation with H α emission is found to correspond to a shorter stellar lifespan, and we conclude that the method can be used as an indicator of the ages, and therefore initial masses, of SN progenitors. We find that the spatial distributions of type II-P SNe and red supergiants of appropriate initial mass ( 9 M ) are consistent with each other. We also find the distributions of type Ic SNe and WN stars with initial masses 20 M consistent, while supergiants with initial masses around 15 M are a better match for type IIb and II-L SNe. The type Ib distribution corresponds to the same stellar types as type II-P, which suggests an origin in interacting binaries. On the other hand, we find that luminous blue variable stars show a much stronger correlation with H α emission than do type IIn SNe.

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“…-the proper motion of the star, obtained from NOMAD, is compatible with the Magellanic Clouds (González-Fernández et al 2015); Fig. 8.…”

Section: Stellar Samplementioning

confidence: 55%

Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies

Kangas

Portinari

Mattila

et al. 2017

A&A

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“…These stars, while yet to be confirmed observationally, are thought to be red giants or supergiants with neutron stars at their cores. Alternatively, it has been suggested it could be a super-AGB star (Wood, Bessell & Fox 1983;Smith & Lambert 1990;Tout et al 2014), or even a Galactic foreground S-type star (Maccarone & de Mink 2016), though its SMC membership seems secure on the basis of the radial velocity of v rad = 150 km s −1 (González-Fernández et al 2015) and proper motion (Worley et al 2016). The position of this source, with respect to the other SMC sources, suggests it is not particularly reddened or luminous at 24 µm.…”

Section: Isolating the Oh/ir Samplementioning

confidence: 95%

“…OGLE SMC-LPV-15504 has a known systemic velocity of 176.8 ± 0.3 km s −1 (Massey & Olsen 2003) from spectroscopic observations of the Ca ii triplet, which greatly simplifies our search in velocity space. HV 12149 has an initial mass of around 4 − 5 M , and is likely to have just initiated HBB (González-Fernández et al 2015;Dell'Agli et al 2015;Slemer et al 2017). This source is unique with its late spectral type yet bright Kband flux of MK = 8.6 mag (Cutri et al 2003), typical of a RSG.…”

Section: Atca Sourcesmentioning

confidence: 99%

A dearth of OH/IR stars in the Small Magellanic Cloud

Goldman

Loon

Gómez

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present the results of targeted observations and a survey of 1612-, 1665-, and 1667-MHz circumstellar OH maser emission from asymptotic giant branch (AGB) stars and red supergiants (RSGs) in the Small Magellanic Cloud (SMC), using the Parkes and Australia Telescope Compact Array radio telescopes. No clear OH maser emission has been detected in any of our observations targeting luminous, long-period, large-amplitude variable stars, which have been confirmed spectroscopically and photometrically to be mid-to late-M spectral type. These observations have probed 3 − 4 times deeper than any OH maser survey in the SMC. Using a bootstrapping method with LMC and Galactic OH/IR star samples and our SMC observation upper limits, we have calculated the likelihood of not detecting maser emission in any of the two sources considered to be the top maser candidates to be less than 0.05%, assuming a similar pumping mechanism as the LMC and Galactic OH/IR sources. We have performed a population comparison of the Magellanic Clouds and used Spitzer IRAC and MIPS photometry to confirm that we have observed all high luminosity SMC sources that are expected to exhibit maser emission. We suspect that, compared to the OH/IR stars in the Galaxy and LMC, the reduction in metallicity may curtail the dusty wind phase at the end of the evolution of the most massive cool stars. We also suspect that the conditions in the circumstellar envelope change beyond a simple scaling of abundances and wind speed with metallicity.

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“…The triplet weakens towards later spectral types and lower luminosity classes (Jaschek & Jaschek 1987), but many other classification criteria are available in this range. In addition, the Mg i triplet (5167, 5173, 5184Å) is very useful for the stars in our sample because of its sensitivity to luminosity (Jaschek & Jaschek 1987;González-Fernández et al 2015). The two Cepheids were also observed, presenting spectral types G2 Iab (V340 Nor) and G1 Iab (QZ Nor).…”

Section: Red Starsmentioning

confidence: 99%

NGC 6067: a young and massive open cluster with high metallicity

Alonso-Santiago

Negueruela

Marco

et al. 2017

Monthly Notices of the Royal Astronomical Society

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NGC 6067 is a young open cluster hosting the largest population of evolved stars among known Milky Way clusters in the 50 -150 Ma age range. It thus represents the best laboratory in our Galaxy to constrain the evolutionary tracks of 5 -7 M stars.We have used high-resolution spectra of a large sample of bright cluster members (45), combined with archival photometry, to obtain accurate parameters for the cluster as well as stellar atmospheric parameters. We derive a distance of 1.78 ± 0.12 kpc, an age of 90 ± 20 Ma and a tidal radius of 14.8 +6.8 −3.2 arcmin. We estimate an initial mass above 5 700 M , for a present-day evolved population of two Cepheids, two A supergiants and 12 red giants with masses ≈ 6 M .We also determine chemical abundances of Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the red clump stars. We find a supersolar metallicity, [Fe/H]=+0.19±0.05, and a homogeneous chemical composition, consistent with the Galactic metallicity gradient. The presence of a Li-rich red giant, star 276 with A(Li)=2.41, is also detected. An over-abundance of Ba is found, supporting the enhanced s-process.The ratio of yellow to red giants is much smaller than one, in agreement with models with moderate overshooting, but the properties of the cluster Cepheids do not seem consistent with current Padova models for supersolar metallicity.

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A new survey of cool supergiants in the Magellanic Clouds

Cited by 68 publications

References 61 publications

Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies

Core-collapse supernova progenitor constraints using the spatial distributions of massive stars in local galaxies

A dearth of OH/IR stars in the Small Magellanic Cloud

NGC 6067: a young and massive open cluster with high metallicity

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