The center of the Type Ia supernova remnant SNR 0509-67.5 is empty of any
ex-companion star to MV=+8.4

Bradley E. Schaefer    Ashley Pagnotta    (Department of Physics and Astronomy, Louisiana State University)

Type Ia supernova (SNe Ia) are thought to originate in the explosion of a white dwarf1. The explosion could be triggered by the merger of two white dwarfs2,3 ('double-degenerate' origin), or by mass transfer from a companion star4,5 (the 'single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin6 has been widely rejected7-11. One way to distinguish between the double- and single-degenerate progenitors is to look at the center of a known SN Ia remnant to see whether any former companion star is present12,13. A likely ex-companion star for the progenitor of Tycho's supernova has been identified14, but that claim is still controversial15-18. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a Type Ia supernova 400±50 years ago, based on its light echo19,20) in the Large Magellanic Cloud contains no ex-companion star to a limit of V=26.9 magnitude (MV=+8.4) within the extreme 99.73% region with radius 1.43”. The lack of any ex-companion star to deep limits rules out all published single-degenerate models. The only remaining possibility is that the progenitor for this particular SN Ia was a double-degenerate system.

Schaefer, B. E. and Pagnotta, A. 2011, Nature, volume 481, published 12 January 2012 -- PDF
Manuscript (plus Supplementary Information) available at http://arxiv.org/abs/1201.2195/


IMAGES

SNR 0509-67.5
Astronomy Picture of the Day
(25 January 2011)
http://apod.nasa.gov/apod/ap110125.html

Caption: SNR 0509-67.5, the Type Ia supernova remnant in the Large Magellanic Cloud. This image was created using data from the Hubble Space Telescope. (HST). The large, diaphanous ellipse is the now-tenuous gas shell ejected by the supernova 400 (±50) years ago. The circle in the middle marks the site of the explosion, and the size of the circle represents the maximum allowed position for any possible ex-companion star after accounting for its motion over the 400 years since the explosion. The error circle has no stars in it. (The nebulous object is a random far-background galaxy of no connection.) The lack of any possible ex-companion stars to deep HST limits rejects all single-degenerate progenitors.

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SNR 0509-67.5
In optical light from the Hubble Heritage Program of the Hubble Space Telescope

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SNR 0509-67.5
With optical and X-ray light from Hubble Space Telescope and the Chandra X-ray Observatory

http://chandra.harvard.edu/photo/2010/snr0509/

Optical and Xray light

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SNR 0509-67.5
With circle that must contain the ex-companion star from Hubble Space Telescope images

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SNR 0509-67.5
In black and white from Hubble Space Telescope Images

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SNR 0519-69.0

Caption: SNR 0519-69.0, the Type Ia supernova remnant in the Large Magellanic Cloud. This image was created using data from the Hubble Space Telescope (HST). The large, diaphanous ellipse is the now-tenuous gas shell ejected by the supernova 600 (±200) years ago. The circle in the middle marks the site of the explosion, and the size of the circle represents the maximum allowed position for any possible ex-companion star after accounting for its motion over the 600 years since the explosion. This circle has many stars in it. Any of the brighter stars inside this circle (all of which are main sequence stars) could be an ex-companion star as predicted by the supersoft source progenitor model. Alternatively, maybe none of these stars is the ex-companion star, because there is no ex-companion as predicted by the double degenerate progenitor model. Importantly, none of the stars in the circle are red giant or subgiant stars, as required by most of the single-degenerate progenitor models (including the symbiotic stars, recurrent novae, helium stars, and spin-up/spin-down systems). The nearest red giant and sub giant stars are marked by "RG" and "SG" in the picture. Thus, out of the many possible ideas for progenitors, only two remain possible for SNR 0519-69.0; the double degenerate model and the supersoft system progenitor model.

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SNR 0519-69.0
In black and white from Hubble Space Telescope images

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PRESS RELEASE

ORIGIN OF THERMONUCLEAR SUPERNOVA DISCOVERED
12:00 P.M. CST, Wednesday, January 11, 2012, at the American Astronomical Society (AAS) meeting in Austin, TX - PDF - Press Conference Talk

 


CONTACT INFORMATION

  • Ashley Pagnotta
    (Louisiana State University, Department of Physics and Astronomy):

    (281) 686-1370 (cell phone, for use during AAS meeting)

  • Prof. Bradley E. Schaefer
    (Louisiana State University, Department of Physics and Astronomy):

    (225) 578-0015 - Department Office; (225) 578-5855 - Department Fax

INDEPENDENT EXPERTS WHO AGREE TO TALK WITH THE PRESS

  • Prof. J. Craig Wheeler
    (Univ. Texas Austin, former AAS president, supernova theorist):

    (512)471-6407

  • Prof. Robert Fesen
    (Dartmouth College, supernova remnant observations):

    (603)646-2949 (Dartmouth office) and 720-536-8011 (during the meeting)

  • Prof. Pilar Ruiz-Lapuente
    (Universidad de Barcelona, supernova and remnant observer):
    or
    934021120

ACKNOWLEDGMENTS

The National Science Foundation supports the work of Schaefer & Pagnotta through a grant in the Astronomy and Astrophysics Division. The National Science Foundation also supported Edwards as part of a Research Experience for Undergraduates program administered by the Louisiana State University in Baton Rouge.

The Hubble Space Telescope and the Hubble Heritage Program took the images that formed the basis of the work being reported. The images were taken under programs with Principal Investigators Keith Noll and John P. Hughes.


Last Update: Thursday, January 12, 2012 10:28 AM