The Canonical Luminous Blue Variable AG Car and Its Neighbor Hen 3-519  Are Much Closer than Previously Assumed

Smith, Nathan; Stassun, Keivan G.

doi:10.3847/1538-3881/aa5d0c

Cited by 10 publications

(19 citation statements)

References 62 publications

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“…This is potentially a big problem for the traditional view of LBVs as massive single stars in transition to the WR phase. While the Gaia DR1 distances to these LBVs are still considered tentative [36], one may anticipate that the second data release from Gaia might shake things up even more.…”

Section: (B) Some Back and Forthmentioning

confidence: 98%

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Luminous blue variables and the fates of very massive stars

Smith¹

2017

Phil. Trans. R. Soc. A.

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Luminous blue variables (LBVs) had long been considered massive stars in transition to the Wolf-Rayet (WR) phase, so their identification as progenitors of some peculiar supernovae (SNe) was surprising. More recently, environment statistics of LBVs show that most of them cannot be in transition to the WR phase after all, because LBVs are more isolated than allowed in this scenario. Additionally, the high-mass H shells around luminous SNe IIn require that some very massive stars above 40 die without shedding their H envelopes, and the precursor outbursts are a challenge for understanding the final burning sequences leading to core collapse. Recent evidence suggests a clear continuum in pre-SN mass loss from super-luminous SNe IIn, to regular SNe IIn, to SNe II-L and II-P, whereas most stripped-envelope SNe seem to arise from a separate channel of lower-mass binary stars rather than massive WR stars.This article is part of the themed issue 'Bridging the gap: from massive stars to supernovae'.

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Section: (B) Some Back and Forthmentioning

confidence: 98%

“…More recently, Smith & Stassun [36] have examined the implications of revised distances to some Galactic LBVs as listed in the Gaia DR1. A surprising result was that the canonical LBV star AG Carinae is actually at a much closer distance than previously thought, which lowers its true luminosity by about a factor of 10.…”

Section: (B) Some Back and Forthmentioning

confidence: 99%

Luminous blue variables and the fates of very massive stars

Smith¹

2017

Phil. Trans. R. Soc. A.

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“…Their LBV samples include 16 stars in the LMC, and three stars in the SMC. They did not consider Milky Way LBVs because the distances and intervening line-of-sight extinction in the plane of the Milky Way are uncertain (Smith & Stassun 2017). In their study, they included LBV candidates with a massive CSM (circumstellar medium) shell that likely indicates a previous LBV-like giant eruption.…”

Section: Observationsmentioning

confidence: 99%

Modelling luminous-blue-variable isolation

Aghakhanloo

Murphy

Smith³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Observations show that luminous blue variables (LBVs) are far more dispersed than massive O-type stars, and Smith & Tombleson suggested that these large separations are inconsistent with a single-star evolution model of LBVs. Instead, they suggested that the large distances are most consistent with binary evolution scenarios. To test these suggestions, we modelled young stellar clusters and their passive dissolution, and we find that, indeed, the standard single-star evolution model is mostly inconsistent with the observed LBV environments. If LBVs are single stars, then the lifetimes inferred from their luminosity and mass are far too short to be consistent with their extreme isolation. This implies that there is either an inconsistency in the luminosityto-mass mapping or the mass-to-age mapping. In this paper, we explore binary solutions that modify the mass-to-age mapping and are consistent with the isolation of LBVs. For the binary scenarios, our crude models suggest that LBVs are rejuvenated stars. They are either the result of mergers or they are mass gainers and received a kick when the primary star exploded. In the merger scenario, if the primary is about 19 M ⊙ , then the binary has enough time to wander far afield, merge and form a rejuvenated star. In the mass-gainer and kick scenario, we find that LBV isolation is consistent with a wide range of kick velocities, anywhere from 0 to ∼ 105 km/s. In either scenario, binarity seems to play a major role in the isolation of LBVs.

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“…Preliminary results from Gaia Data Release 1 (DR1; Gaia Collaboration et al 2016a,b;Lindegren et al 2016), which includes 43 of the Carina Nebula's O-type stars, support this interpretation. The inferred parallax-based distances, as computed by Astraatmadja & Bailer-Jones (2016) using a prior based on the distribution of stars in the Milky Way, are distributed unimodally around ∼ 2 kpc (Smith & Stassun 2017).…”

Section: Introductionmentioning

confidence: 99%

A radial velocity survey of the Carina Nebula's O-type stars

Kiminki

Smith

2018

Monthly Notices of the Royal Astronomical Society

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We have obtained multi-epoch observations of 31 O-type stars in the Carina Nebula using the CHIRON spectrograph on the CTIO/SMARTS 1.5-m telescope. We measure their radial velocities to 1-2 km s −1 precision and present new or updated orbital solutions for the binary systems HD 92607, HD 93576, HDE 303312, and HDE 305536. We also compile radial velocities from the literature for 32 additional O-type and evolved massive stars in the region. The combined data set shows a mean heliocentric radial velocity of 0.6 km s −1 . We calculate a velocity dispersion of ≤ 9.1 km s −1 , consistent with an unbound, substructured OB association. The Tr 14 cluster shows a marginally significant 5 km s −1 radial velocity offset from its neighbor Tr 16, but there are otherwise no correlations between stellar position and velocity. The O-type stars in Cr 228 and the South Pillars region have a lower velocity dispersion than the region as a whole, supporting a model of distributed massive-star formation rather than migration from the central clusters. We compare our stellar velocities to the Carina Nebula's molecular gas and find that Tr 14 shows a close kinematic association with the Northern Cloud. In contrast, Tr 16 has accelerated the Southern Cloud by 10-15 km s −1 , possibly triggering further massive-star formation. The expansion of the surrounding H ii region is not symmetric about the O-type stars in radial velocity space, indicating that the ionized gas is constrained by denser material on the far side.

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The Canonical Luminous Blue Variable AG Car and Its Neighbor Hen 3-519 Are Much Closer than Previously Assumed

Cited by 10 publications

References 62 publications

Luminous blue variables and the fates of very massive stars

Luminous blue variables and the fates of very massive stars

Modelling luminous-blue-variable isolation

A radial velocity survey of the Carina Nebula's O-type stars

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