Scientists detect a type Ia supernova at birth
These observations represent a major step forward in the understanding of this type of supernova and make it possible to distinguish between different explosion patterns.
The results of the study, in which the researcher from the Institute of Space Sciences (ICE-CSIC) and member of the IEEC Lluís Galbany participates, have been published in the journal Nature Astronomy.
An international team led by researchers from the Dunlap Institute at the University of Toronto has carried out the earliest detection of a type Ia supernova, since scientists have been able to observe it from the moment of its birth. The study involves the participation of Lluís Galbany, a researcher at the Institute of Space Sciences (ICE-CSIC) and member of the Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya), and the results have been published in the scientific journal Nature Astronomy.
The observed supernova, called SN 2018aoz, is a type Ia supernova that exploded on 29 March 2018. Supernovae are very luminous and energetic stellar explosions, which occur at the end of a star's life. Among them, type Ia supernovae are thermonuclear explosions of white dwarfs in binary systems, and are the most commonly observed variety of supernovae. They are crucial for understanding the origin of metals and the accelerating expansion of the Universe. Despite their importance, there are still many unanswered questions about their origins, as the explosion mechanisms of type Ia supernovae are still subject of debate among the scientific community.
The rapid detection of SN 2018aoz was made possible by means of the Korea Microlensing Telescope Network (KMTNet), a network consisting of three telescopes located in the southern hemisphere, with sites in Chile, South Africa and Australia. The science team was able to detect SN 2018aoz from one hour after its first light, which is the earliest multi-band detection of a type Ia supernova to date. In addition, it has also been possible to obtain information about its birth, which is crucial to reveal how the explosion took place.
ICE-CSIC has contributed to the study with infrared observations from the Cerro Tololo Inter-American Observatory, in Chile, using the ANDICAM (‘A Novel Dual Imaging CAMera’) instrument of the SMARTS telescope. "SN 2018aoz is part of a set of type Ia supernovae that we were observing in the infrared to measure distances to their galaxies and thus be able to determine the expansion rate of the local Universe," explains Dr Galbany. "This SN was the closest of the ones we were following—and it also turned out to be the brightest of 2018—so we planned to observe it more frequently. As soon as our Canadian collaborators notified us of the early discovery, we decided to follow it up more closely," he says.
A rapid reddening of the light in the first few hours
SN 2018aoz is the earliest detection of a type Ia supernova to date. But its detection is rather faint, as it took between two and three weeks from the time the supernova exploded to the peak of the light emitted. The data reveal a concentration of metals—from the iron family— in the outermost layer of the material ejected by the supernova. This reveals a rapid reddening of its light, i.e. a temporary absorption of its bluer light, during the first twelve hours of the supernova's life.
This discovery indicates that normal type Ia supernova explosions could be initiated by the burning of material on the surface of the dying star or by an extreme mixing process that causes heavier elements from the interior to emerge to the surface. These observations are a very important milestone in the understanding of how type Ia supernovae explode. Furthermore, these very early data allow us to distinguish between different models of type Ia supernovae explosions, as the results seem to indicate that the model that best explains the observations is a 'double detonation' model, in which the outburst of the outermost layer of a white dwarf would cause a shock wave with enough energy to trigger another detonation in the centre of the star.
Press release made in collaboration with the Institute of Space Sciences (ICE-CSIC) and the Communication Office of the Delegation in Catalonia of the Spanish Research Council (CSIC).
Main Image
Caption: Remnant of Kepler's Type Ia supernova, the famous explosion that was discovered by Johannes Kepler in 1604.
Credits: NASA / CXC / Univ. of Texas at Arlington / M. Millard et al.
Links
– IEEC
– ICE-CSIC
– Dunlap Institute
– KMTNet
More information
This research is presented in a paper entitled “Infant-phase reddening by surface Fe-peak elements in a normal type Ia supernova”, by Qi Ni, Y. et al., that appeared in the journal Nature Astronomy on 17 February 2022.
The Institute of Space Studies of Catalonia (IEEC — Institut d’Estudis Espacials de Catalunya) promotes and coordinates space research and technology development in Catalonia for the benefit of society. IEEC fosters collaborations both locally and worldwide and is an efficient agent of knowledge, innovation and technology transfer. As a result of 25 years of high-quality research, done in collaboration with major international organisations, IEEC ranks among the best international research centers, focusing on areas such as: astrophysics, cosmology, planetary science, and Earth Observation. IEEC’s engineering division develops instrumentation for ground- and space-based projects, and has extensive experience in working with private or public organisations from the aerospace and other innovation sectors.
IEEC is a private non-profit foundation, governed by a Board of Trustees composed of Generalitat de Catalunya and four other institutions that each have a research unit, which together constitute the core of IEEC R&D activity: the Universitat de Barcelona (UB) with the research unit ICCUB — Institute of Cosmos Sciences; the Universitat Autònoma de Barcelona (UAB) with the research unit CERES — Center of Space Studies and Research; the Universitat Politècnica de Catalunya · BarcelonaTech (UPC) with the research unit CTE — Research Group in Space Sciences and Technologies; the Spanish Research Council (CSIC) with the research unit ICE — Institute of Space Sciences. IEEC is a CERCA (Centres de Recerca de Catalunya) center.
Contacts
IEEC Communication Office
Barcelona, Spain
Ana Montaner and Rosa Rodríguez
E-mail: comunicacio@ieec.cat
Lead Researcher at IEEC
Barcelona, Spain
Lluís Galbany
Institute of Space Sciences (ICE-CSIC)
Institute of Space Studies of Catalonia (IEEC)
E-mail: lgalbany@ieec.cat, lgalbany@ice.csic.es