Hiding in plain sight-red supergiant imposters? Super-AGB stars

Carolyn Doherty, Pilar Gil-Pons, John Lattanzio, Lionel Siess

Research output: Contribution to conferenceAbstract

Abstract

Super Asymptotic Giant Branch (Super-AGB) stars reside in the mass range ≈ 6.5-10 M⊙ and bridge the divide between low/intermediate-mass and massive stars. They are characterised by off-centre carbon ignition prior to a thermally pulsing phase which can consist of many tens to even thousands of thermal pulses. With their high luminosities and very large, cool, red stellar envelopes, these stars appear seemingly identical to their slightly more massive red supergiant counterparts. Due to their similarities, super-AGB stars may therefore act as stellar imposters and contaminate red supergiant surveys. The final fate of super-AGB stars is also quite uncertain and depends primarily on the competition between the core growth and mass-loss rates. If the stellar envelope is removed prior to the core reaching ≈ 1.375 M⊙, an O-Ne white dwarf will remain, otherwise the star will undergo an electron-capture supernova (EC-SN) leaving behind a neutron star. We determine the relative fraction of super-AGB stars that end life as either an O-Ne white dwarf or as a neutron star, and provide a mass limit for the lowest mass supernova over a broad range of metallicities from the Z=0.02 to 0.0001.

Original languageEnglish
Pages446
Number of pages1
DOIs
Publication statusPublished - 2015
EventIAU General Assembly 2015 - Honolulu, United States of America
Duration: 3 Aug 201514 Aug 2015
Conference number: 29th
http://astronomy2015.org/

Conference

ConferenceIAU General Assembly 2015
Abbreviated titleIAU GA 2015
CountryUnited States of America
CityHonolulu
Period3/08/1514/08/15
Internet address

Keywords

  • evolution
  • stars: AGB and post-AGB
  • stars: supernovae: general
  • stars: white dwarfs

Cite this