scholarly journals Predicting the nature of supernova progenitors

2017 ◽  
Vol 375 (2105) ◽  
pp. 20170219 ◽  
Author(s):  
Jose H. Groh
Keyword(s):  
High Resolution ◽  
Physical Properties ◽  
Stellar Evolution ◽  
Massive Stars ◽  
High Resolution Spectrum ◽  
Core Collapse ◽  
Single Star ◽  
Luminous Blue Variables ◽  
Star Models ◽  
Red Supergiants

Stars more massive than about 8 solar masses end their lives as a supernova (SN), an event of fundamental importance Universe-wide. The physical properties of massive stars before the SN event are very uncertain, both from theoretical and observational perspectives. In this article, I briefly review recent efforts to predict the nature of stars before death, in particular, by performing coupled stellar evolution and atmosphere modelling of single stars in the pre-SN stage. These models are able to predict the high-resolution spectrum and broadband photometry, which can then be directly compared with the observations of core-collapse SN progenitors. The predictions for the spectral types of massive stars before death can be surprising. Depending on the initial mass and rotation, single star models indicate that massive stars die as red supergiants, yellow hypergiants, luminous blue variables and Wolf–Rayet stars of the WN and WO subtypes. I finish by assessing the detectability of SN Ibc progenitors. This article is part of the themed issue ‘Bridging the gap: from massive stars to supernovae’.

scholarly journals Massive stars in their death throes

2008 ◽  
Vol 366 (1884) ◽  
pp. 4441-4452 ◽  
Author(s):  
John J Eldridge
Keyword(s):  
Stellar Evolution ◽  
Massive Stars ◽  
Evolution Theory ◽  
Luminous Blue Variables ◽  
Show Evidence ◽  
Red Supergiants ◽  
Working Backwards

The study of the stars that explode as supernovae used to be a forensic study, working backwards from the remnants of the star. This changed in 1987 when the first progenitor star was identified in pre-explosion images. Currently, there are eight detected progenitors with another 21 non-detections, for which only a limit on the pre-explosion luminosity can be placed. This new avenue of supernova research has led to many interesting conclusions, most importantly that the progenitors of the most common supernovae, type IIP, are red supergiants, as theory has long predicted. However, no progenitors have been detected thus far for the hydrogen-free type Ib/c supernovae, which, given the expected progenitors, is an unlikely result. Also, observations have begun to show evidence that luminous blue variables, which are among the most massive stars, may directly explode as supernovae. These results contradict the current stellar evolution theory. This suggests that we may need to update our understanding.

scholarly journals Combined stellar evolution and spectroscopic modeling of massive stars

2015 ◽  
Vol 11 (A29B) ◽  
pp. 455-457
Author(s):  
Jose H. Groh
Keyword(s):  
High Resolution ◽  
Stellar Evolution ◽  
Massive Star ◽  
Massive Stars ◽  
Atmospheric Modeling ◽  
High Resolution Spectrum ◽  
Morphological Appearance ◽  
First Time

AbstractThe morphological appearance of massive stars during their evolution and at the pre-SN stage is very uncertain, both from theoretical and observational perspectives. We recently developed coupled stellar evolution and atmospheric modeling of stars done with the Geneva and CMFGEN codes, for initial masses between 9 and 120 M⊙. We are able to predict the observables such as the high-resolution spectrum and broadband photometry. Here I discuss how the spectrum of a massive star changes across its evolution and before death. Our models allow, for the first time, direct comparison between predictions from stellar evolution models and observations of SN progenitors.

scholarly journals Red supergiants as supernova progenitors

2017 ◽  
Vol 375 (2105) ◽  
pp. 20160270 ◽  
Author(s):  
Ben Davies
Keyword(s):  
Mass Spectrum ◽  
Physical Properties ◽  
Evolutionary Theory ◽  
Massive Stars ◽  
Red Supergiants ◽  
Physical Quantities ◽  
Appearance Changes

It is now well-established from pre-explosion imaging that red supergiants (RSGs) are the direct progenitors of Type-IIP supernovae. These images have been used to infer the physical properties of the exploding stars, yielding some surprising results. In particular, the differences between the observed and predicted mass spectrum has provided a challenge to our view of stellar evolutionary theory. However, turning what is typically a small number of pre-explosion photometric points into the physical quantities of stellar luminosity and mass requires a number of assumptions about the spectral appearance of RSGs, as well as their evolution in the last few years of life. Here I will review what we know about RSGs, with a few recent updates on how they look and how their appearance changes as they approach supernova. This article is part of the themed issue ‘Bridging the gap: from massive stars to supernovae’.

scholarly journals The Physical Properties of Red Supergiants: Comparing Theory and Observations

2007 ◽  
Vol 3 (S250) ◽  
pp. 97-110 ◽  
Author(s):  
Philip Massey ◽  
Emily M. Levesque ◽  
Bertrand Plez ◽  
Knut A. G. Olsen
Keyword(s):  
Physical Properties ◽  
Milky Way ◽  
Massive Stars ◽  
Stellar Atmospheres ◽  
Circumstellar Dust ◽  
Evolutionary Models ◽  
Dust Source ◽  
Look Back ◽  
Red Supergiants ◽  
Effective Temperatures

AbstractRed supergiants (RSGs) are an evolved stage in the life of intermediate massive stars (≤ 25 M⊙). For many years, their location in the H-R diagram was at variance with the evolutionary models. Using the MARCS stellar atmospheres, we have determined new effective temperatures and bolometric luminosities for RSGs in the Milky Way, LMC, and SMC, and our work has resulted in much better agreement with the evolutionary models. We have also found evidence of significant visual extinction due to circumstellar dust. Although in the Milky Way the RSGs contribute only a small fraction (< 1%) of the dust to the interstellar medium (ISM), in starburst galaxies or galaxies at large look-back times, we expect that RSGs may be the main dust source. We are in the process of extending this work now to RSGs of higher and lower metallicities using the galaxies M31 and WLM.

scholarly journals The Impact of Realistic Red Supergiant Mass Loss on Stellar Evolution

2021 ◽  
Vol 922 (1) ◽  
pp. 55
Author(s):  
Emma R. Beasor ◽  
Ben Davies ◽  
Nathan Smith
Keyword(s):  
Mass Loss ◽  
Stellar Evolution ◽  
Massive Stars ◽  
Light Curves ◽  
Core Collapse ◽  
Strong Impact ◽  
Type Ii ◽  
Evolutionary Models ◽  
Cool Star ◽  
The Impact

Abstract Accurate mass-loss rates are essential for meaningful stellar evolutionary models. For massive single stars with initial masses between 8 and 30M ⊙the implementation of cool supergiant mass loss in stellar models strongly affects the resulting evolution, and the most commonly used prescription for these cool-star phases is that of de Jager. Recently, we published a new M ̇ prescription calibrated to RSGs with initial masses between 10 and 25 M ⊙, which unlike previous prescriptions does not overestimate M ̇ for the most massive stars. Here, we carry out a comparative study to the MESA-MIST models, in which we test the effect of altering mass loss by recomputing the evolution of stars with masses 12–27 M ⊙ with the new M ̇ -prescription implemented. We show that while the evolutionary tracks in the HR diagram of the stars do not change appreciably, the mass of the H-rich envelope at core collapse is drastically increased compared to models using the de Jager prescription. This increased envelope mass would have a strong impact on the Type II-P SN lightcurve, and would not allow stars under 30 M ⊙ to evolve back to the blue and explode as H-poor SN. We also predict that the amount of H-envelope around single stars at explosion should be correlated with initial mass, and we discuss the prospects of using this as a method of determining progenitor masses from supernova light curves.

scholarly journals The Supernova/GRB Connection

2005 ◽  
Vol 192 ◽  
pp. 403-410 ◽  
Author(s):  
P. Höflich ◽  
D. Baade ◽  
A. Khokhlov ◽  
L. Wang ◽  
J.C. Wheeler
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Central Region ◽  
Stellar Evolution ◽  
Axial Symmetry ◽  
Energy Deposition ◽  
Gamma Ray ◽  
Massive Stars ◽  
Core Collapse ◽  
Supernova Explosions

SummaryWe discuss the possible connection between supernova explosions (SN) and gamma-ray bursters (GRB) from the perspective of our current understanding of SN physics. Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS) or black hole, and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but detailed models do not produce powerful explosions. There is new and mounting evidence for an asphericity and, in particular, for axial symmetry in several supernovae which may be hard to reconcile within the spherical picture. The 3-D signatures are a key to understand core collapse supernovae and the GRB/SN connection. In this paper we study the effects and observational consequences of asymmetric explosions.

scholarly journals Ring Nebulae Around Massive Stars

1991 ◽  
Vol 143 ◽  
pp. 349-364
Author(s):  
You-Hua Chu
Keyword(s):  
Stellar Evolution ◽  
Spectral Properties ◽  
Massive Stars ◽  
Ambient Medium ◽  
Stellar Winds ◽  
Luminous Blue Variables ◽  
Stellar Properties ◽  
Ring Nebulae ◽  
Central Stars ◽  
Temperature Correlations

Ring nebulae have been found around WR stars, OB and Of stars, and luminous blue variables. Ring nebulae are formed by the interaction between the central stars and their ambient medium via different combinations of stellar winds, ejecta, and radiation. The spectral properties of the nebulae can be used to diagnose the stellar properties, such as luminosity and effective temperature. Correlations between ring nebulae and their central stars may be used to check scenarios of stellar evolution.

scholarly journals Dusty LBV Nebulae: Tracing the Mass Loss History of the Most Massive Stars

1999 ◽  
Vol 169 ◽  
pp. 381-390
Author(s):  
Laurens B.F.M. Waters ◽  
Robert H.M. Voors ◽  
Patrick W. Morris ◽  
Norman R. Trams ◽  
Alex de Koter ◽  
...  
Keyword(s):  
Massive Stars ◽  
High Ratio ◽  
Agb Stars ◽  
Space Observatory ◽  
Dust Shells ◽  
Luminous Blue Variables ◽  
Dust Composition ◽  
Red Supergiants ◽  
History Of ◽  
Similar Processing

AbstractWe present spectra obtained with the Infared Space Observatory (ISO) of the dust shells surrounding several Luminous Blue Variables (LBVs), both in our galaxy and in the LMC. The 20-45 μm spectra of R71, AG Car and Wra 751 show prominent emission features from crystalline silicates. The composition of the crystalline silicates in LBV dust shells is compared to that found in other types of objects, such as (post)-AGB stars and red supergiants (RSG). Both Wra 751 and AG Car have a high ratio of pyroxenes to olivines. This suggests that the grains in both stars experienced very similar processing, but that this processing has lead to a higher abundance of pyroxenes compared to RSG. The dust composition of the three LBVs discussed here suggests dust formation in a cool outflow not unlike those of RSG.

scholarly journals About the Luminous Blue Variable He3-519

2010 ◽  
Vol 6 (S272) ◽  
pp. 87-88
Author(s):  
Anthony Hervé ◽  
Jean-Claude Bouret
Keyword(s):  
Stellar Evolution ◽  
Time Scale ◽  
Massive Stars ◽  
Model Atmosphere ◽  
Transition Phase ◽  
Evolutionary Status ◽  
Stellar Winds ◽  
Luminous Blue Variables ◽  
Luminous Blue Variable

AbstractLuminous Blue Variables (LBVs) are massive stars, in a transition phase, from being O-type stars and rapidly becoming Wolf-Rayet objects. LBVs possess powerful stellar winds, high luminosities and show photometric and spectroscopic variability. We present the stellar and wind parameters of He3-519 obtained by the modeling of UVES observations with the model atmosphere code CMFGEN. We compare our results to previous studies in order to find mid-time scale variability of the stellar parameters and finally, we use stellar evolution models to determine the evolutionary status of this star.

scholarly journals DIVISION IV / WORKING GROUP MASSIVE STARS

2008 ◽  
Vol 4 (T27A) ◽  
pp. 236-239
Author(s):  
Stanley P. Owocki ◽  
Paul A. Crowther ◽  
Alexander W. Fullerton ◽  
Gloria Koenigsberger ◽  
Norbert Langer ◽  
...  
Keyword(s):  
Working Group ◽  
Gamma Ray ◽  
Massive Stars ◽  
Gamma Ray Bursts ◽  
Core Collapse ◽  
Hot Stars ◽  
First Stars ◽  
Ob Stars ◽  
Red Supergiants

Our Working Group studies massive, luminous stars, with historical focus on early-type (OB) stars, but extending in recent years to include massive red supergiants that evolve from hot stars. There is also emphasis on the role of massive stars in other branches of astrophysics, particularly regarding starburst galaxies, the first stars, core-collapse gamma-ray bursts, and formation of massive stars.

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