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Title: THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED

Abstract

Hubble Space Telescope observations of the site of the supernova (SN) SN 2008ax obtained in 2011 and 2013 reveal that the possible progenitor object detected in pre-explosion images was in fact multiple. Four point sources are resolved in the new, higher-resolution images. We identify one of the sources with the fading SN. The other three objects are consistent with single supergiant stars. We conclude that their light contaminated the previously identified progenitor candidate. After subtraction of these stars, the progenitor appears to be significantly fainter and bluer than previously measured. Post-explosion photometry at the SN location indicates that the progenitor object has disappeared. If single, the progenitor is compatible with a supergiant star of B to mid-A spectral type, while a Wolf–Rayet (W-R) star would be too luminous in the ultraviolet to account for the observations. Moreover, our hydrodynamical modeling shows that the pre-explosion mass was 4–5 M{sub ⊙} and the radius was 30–50 R{sub ⊙}, which is incompatible with a W-R progenitor. We present a possible interacting binary progenitor computed with our evolutionary models that reproduces all the observational evidence. A companion star as luminous as an O9–B0 main-sequence star may have remained after the explosion.

Authors:
; ;  [1];  [2]; ;  [3]
  1. Instituto de Astrofísica de La Plata (Argentina)
  2. Millennium Institute of Astrophysics (MAS), Casilla 36-D, Santiago (Chile)
  3. Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)
Publication Date:
OSTI Identifier:
22525306
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 811; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; IMAGES; MAIN SEQUENCE STARS; MASS; PHOTOMETRY; RESOLUTION; SPACE; SUPERGIANT STARS; SUPERNOVAE; TELESCOPES; ULTRAVIOLET RADIATION; VISIBLE RADIATION; WOLF-RAYET STARS

Citation Formats

Folatelli, Gastón, Bersten, Melina C., Benvenuto, Omar G., Kuncarayakti, Hanindyo, Maeda, Keiichi, and Nomoto, Ken’ichi, E-mail: gaston@fcaglp.unlp.edu.ar. THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED. United States: N. p., 2015. Web. doi:10.1088/0004-637X/811/2/147.
Folatelli, Gastón, Bersten, Melina C., Benvenuto, Omar G., Kuncarayakti, Hanindyo, Maeda, Keiichi, & Nomoto, Ken’ichi, E-mail: gaston@fcaglp.unlp.edu.ar. THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED. United States. doi:10.1088/0004-637X/811/2/147.
Folatelli, Gastón, Bersten, Melina C., Benvenuto, Omar G., Kuncarayakti, Hanindyo, Maeda, Keiichi, and Nomoto, Ken’ichi, E-mail: gaston@fcaglp.unlp.edu.ar. Thu . "THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED". United States. doi:10.1088/0004-637X/811/2/147.
@article{osti_22525306,
title = {THE PROGENITOR OF THE TYPE IIb SN 2008ax REVISITED},
author = {Folatelli, Gastón and Bersten, Melina C. and Benvenuto, Omar G. and Kuncarayakti, Hanindyo and Maeda, Keiichi and Nomoto, Ken’ichi, E-mail: gaston@fcaglp.unlp.edu.ar},
abstractNote = {Hubble Space Telescope observations of the site of the supernova (SN) SN 2008ax obtained in 2011 and 2013 reveal that the possible progenitor object detected in pre-explosion images was in fact multiple. Four point sources are resolved in the new, higher-resolution images. We identify one of the sources with the fading SN. The other three objects are consistent with single supergiant stars. We conclude that their light contaminated the previously identified progenitor candidate. After subtraction of these stars, the progenitor appears to be significantly fainter and bluer than previously measured. Post-explosion photometry at the SN location indicates that the progenitor object has disappeared. If single, the progenitor is compatible with a supergiant star of B to mid-A spectral type, while a Wolf–Rayet (W-R) star would be too luminous in the ultraviolet to account for the observations. Moreover, our hydrodynamical modeling shows that the pre-explosion mass was 4–5 M{sub ⊙} and the radius was 30–50 R{sub ⊙}, which is incompatible with a W-R progenitor. We present a possible interacting binary progenitor computed with our evolutionary models that reproduces all the observational evidence. A companion star as luminous as an O9–B0 main-sequence star may have remained after the explosion.},
doi = {10.1088/0004-637X/811/2/147},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 811,
place = {United States},
year = {2015},
month = {10}
}