Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars

August 20, 2014
A white dwarf fed by a normal star reaches the critical mass and explodes as a type Ia supernova. Credit: NASA/CXC/M Weiss

Type Ia supernovae happen when a white dwarf, the "corpse" of a star similar to the Sun, absorbs material from a twin star until it reaches a critical mass—1.4 times that of the Sun—and explodes. Because of their origin, all these explosions share a very similar luminosity. This uniformity made type Ia supernovae ideal objects to measure distances in the universe, but the study of supernova 2014J suggests a scenario that would invalidate them as "standard candles".

"Type Ia supernovae are considered because their constitution is very homogeneous and practically all of them reach the same maximum luminosity. They even allowed us to discover that the universe was expanding at an accelerating rate. However, we still don't know what stellar systems give rise to this type of supernovae," says Miguel Ángel Pérez Torres, researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) in charge of the study.

A new model postulating the fusion of two is now challenging the predominant one, consisting of a white dwarf and a normal star. The new scenario does not imply the existence of a maximum mass limit and will not, therefore, necessarily produce explosions of similar luminosity.

SN 2014J, a supernova very near by

The results mentioned above were obtained from the study of supernova 2014J, situated 11.4 million light years away from our planet, using the EVN and eMERLIN networks of radio telescopes. "It is a phenomenon that very seldom occurs in our immediate universe. 2014J has been the Ia type supernova closest to us since 1986, when the telescopes were much less sensitive, and it may well be the only one we'll be able to observe in such vicinity in the next one hundred and fifty years," says Pérez Torres (IAA-CSIC).

The merger of two white dwarfs gives rise to a type Ia supernova. Credit: NASA/CXC/M Weiss

Radio observation makes it possible to reveal what stellar systems lie behind type Ia supernovae. If the explosion proceeds from a white dwarf being nourished by a twin star, for example, a great amount of gas should be present in the environment; after the explosion, the material ejected by the supernova will collide with this gas and produce an intense emission of X rays and radio waves. By contrast, a couple of white dwarfs will not generate this gaseous envelope and, therefore, there will be no emission of either X rays or radio waves.

"We have not detected radio emissions on SN 2014J, which favours the second scenario", says Pérez Torres. "If these results were to gain general acceptance, the cosmological consequences would be weighty, because the use of type Ia to measure distances would come into question," the researcher concludes.

Explore further: One supernova type, two different sources

More information: M. A. Perez-Torres, P. Lundqvist, R. J. Beswick, C. I. Bjornsson, T. W. B. Muxlow, Z. Paragi, S. Ryder, A. Alberdi, C. Fransson, J. M. Marcaide, I. Marti-Vidal, E. Ros, M. K. Argo, J. C. Guirado. "Constraints on the progenitor system and the environs of SN 2014J from deep radio observations." Astrophysical Journal. ApJ, vol. 792, p. 38.

Related Stories

One supernova type, two different sources

May 7, 2012

The exploding stars known as Type Ia supernovae serve an important role in measuring the universe, and were used to discover the existence of dark energy. They're bright enough to see across large distances, and similar enough ...

Supernova progenitor found?

August 3, 2012

(Phys.org) -- Type Ia supernovae are violent stellar explosions. Observations of their brightness are used to determine distances in the universe and have shown scientists that the universe is expanding at an accelerating ...

Hubble monitors supernova in nearby galaxy M82

February 26, 2014

This is a Hubble Space Telescope composite image of a supernova explosion designated SN 2014J in the galaxy M82. At a distance of approximately 11.5 million light-years from Earth it is the closest supernova of its type discovered ...

Recommended for you

New Horizons team selects potential Kuiper Belt flyby target

August 29, 2015

NASA has selected the potential next destination for the New Horizons mission to visit after its historic July 14 flyby of the Pluto system. The destination is a small Kuiper Belt object (KBO) known as 2014 MU69 that orbits ...

Prawn Nebula: Cosmic recycling

September 2, 2015

Dominating this image is part of the nebula Gum 56, illuminated by the hot bright young stars that were born within it. For millions of years stars have been created out of the gas in this nebula, material which is later ...

Image: Hubble sees a youthful cluster

August 31, 2015

Shown here in a new image taken with the Advanced Camera for Surveys (ACS) on board the NASA/ESA Hubble Space Telescope is the globular cluster NGC 1783. This is one of the biggest globular clusters in the Large Magellanic ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Urgelt
not rated yet Aug 21, 2014
So the big question is, if type 1a supernovae are always a pair of white dwarfs that collide, just how much luminosity variance is there among type 1a supernovae?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.