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Art of Modeling Stellar Mergers and the Case of the B[e] Supergiant R4 in the Small Magellanic Cloud

Wu, Samantha and Everson, Rosa Wallace and Schneider, Fabian R. N. and Podsiadlowski, Philipp and Ramirez-Ruiz, Enrico (2020) Art of Modeling Stellar Mergers and the Case of the B[e] Supergiant R4 in the Small Magellanic Cloud. Astrophysical Journal, 901 (1). Art. No. 44. ISSN 1538-4357. doi:10.3847/1538-4357/abaf48.

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Most massive stars exchange mass with a companion, leading to evolution which is altered drastically from that expected of stars in isolation. Such systems result from unusual binary evolution pathways and can place stringent constraints on the physics of these interactions. We use the R4 binary system's B[e] supergiant, which has been postulated to be the product of a stellar merger, to guide our understanding of such outcomes by comparing observations of R4 to the results of simulating a merger with the 3D hydrodynamics code FLASH. Our approach tailors the simulation initial conditions to observed properties of R4 and implements realistic stellar profiles from the 1D stellar evolution code MESA onto the 3D grid, resolving the merger inspiral to within 0.02 R⊙. We map the merger remnant into MESA to track its evolution on the H-R diagram over a period of 10⁴ yr. This generates a model for a B[e] supergiant with stellar properties, age, and nebula structure in qualitative agreement with those of the R4 system. Our calculations provide evidence to support the idea that R4's B[e] supergiant was originally a member of a triple system in which the inner binary merged after its most massive member evolved off the main sequence, producing a new object of similar mass but significantly more luminosity than the A supergiant companion. The code framework presented in this paper, which was constructed to model tidal encounters, can be used to generate accurate models of a wide variety of merger stellar remnants.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wu, Samantha0000-0003-2872-5153
Everson, Rosa Wallace0000-0001-5256-3620
Schneider, Fabian R. N.0000-0002-5965-1022
Podsiadlowski, Philipp0000-0002-8338-9677
Ramirez-Ruiz, Enrico0000-0003-2558-3102
Additional Information:© 2020 The American Astronomical Society. Received 2020 June 6; revised 2020 August 10; accepted 2020 August 12; published 2020 September 21. We gratefully acknowledge helpful discussions with D. Lee, S. de Mink, I. Mandel, P. Macias, A. Antoni, M. MacLeod, and J. Law-Smith. We also thank the referee for very useful comments and suggestions. We thank the Niels Bohr Institute for its hospitality while part of this work was completed and acknowledge the Kavli Foundation and the DNRF for supporting the 2017 Kavli Summer Program. E.R.-R. and R.W.E. thank the David and Lucile Packard Foundation, the Heising-Simons Foundation, and the Danish National Research Foundation (DNRF132) for support. R.W.E. is supported by the Eugene V. Cota-Robles Fellowship and National Science Foundation Graduate Research Fellowship Program (Award #1339067). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. The software used in this work was developed in part by the DOE NNSA ASC- and DOE Office of Science ASCR-supported Flash Center for Computational Science at the University of Chicago. Resources supporting this work were provided by the University of Copenhagen high-performance computing cluster funded by a grant from VILLUM FONDEN (project number 16599).
Funding AgencyGrant Number
Kavli FoundationUNSPECIFIED
Danish National Research FoundationDNRF132
David and Lucile Packard FoundationUNSPECIFIED
Heising-Simons FoundationUNSPECIFIED
Eugene V. Cota-Robles FellowshipUNSPECIFIED
NSF Graduate Research FellowshipDGE-1339067
Subject Keywords:Binary stars ; Stellar mergers ; Hydrodynamical simulations
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Binary stars (154); Stellar mergers (2157); Hydrodynamical simulations (767)
Record Number:CaltechAUTHORS:20200923-103751002
Persistent URL:
Official Citation:Samantha Wu et al 2020 ApJ 901 44
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105488
Deposited By: Tony Diaz
Deposited On:23 Sep 2020 18:15
Last Modified:16 Nov 2021 18:43

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