Jul 8, 2021 05:32 PM
Nova explosions alone cannot explain amount of lithium in current universe
https://www.nao.ac.jp/en/news/science/20...ubaru.html
RELEASE: A new study of lithium production in a classical nova found a production rate of only a couple of percent that seen in other examples. This shows that there is a large diversity within classical novae and implies that nova explosions alone cannot explain the amount of lithium seen in the current Universe.
This is an important result for understanding both the explosion mechanism of classical novae and the overall chemical evolution of the Universe.
In the modern world, lithium is used in the rechargeable batteries powering smartphones and other devices. It was thought that most of the lithium found on Earth, and the rest of the Universe, was originally produced in classical nova explosions.
Observations of the classical nova V339 Del using the Subaru Telescope supported this theory, providing the first observational evidence of large amounts of lithium being produced and ejected into space (Classical Nova Explosions are Major Lithium Factories in the Universe on February 18, 2015).
Now, a team led by Akira Arai, a researcher at Koyama Astronomical Observatory of Kyoto Sangyo University, used the Subaru Telescope's open-use observation program to study V5669 Sgr, a classical nova that appeared in Sagittarius in 2015. This was only the eighth time this type of study has been successfully conducted. Four of those eight, including the first, were conducted using the Subaru Telescope.
This time is remarkable because the estimated lithium production is only a few percent of the production seen in the others. This indicates that there is a large diversity in novae. The fact that some novae produce only a small amount of lithium suggests that other objects, such as supernovae, may make important contributions to lithium production in the Universe.
We found a new type of stellar explosion that could explain a 13-billion-year-old mystery of the Milky Way’s elements
https://theconversation.com/we-found-a-n...nts-163986
INTRO: Until recently it was thought neutron star mergers were the only way heavy elements (heavier than Zinc) could be produced. These mergers involve the mashup of the remnants of two massive stars in a binary system.
But we know heavy elements were first produced not long after the Big Bang, when the universe was really young. Back then, not enough time had passed for neutron star mergers to have even occurred. Thus, another source was needed to explain the presence of early heavy elements in the Milky Way.
The discovery of an ancient star SMSS J2003-1142 in the Milky Way’s halo — which is the roughly spherical region that surrounds the galaxy — is providing the first evidence for another source for heavy elements, including uranium and possibly gold.
In our research published today in Nature, we show the heavy elements detected in SMSS J2003-1142 were likely produced, not by a neutron star merger, but through the collapse and explosion of a rapidly spinning star with a strong magnetic field and a mass about 25 times that of the Sun.
We call this explosion event a “magnetorotational hypernova”... (MORE)
https://www.nao.ac.jp/en/news/science/20...ubaru.html
RELEASE: A new study of lithium production in a classical nova found a production rate of only a couple of percent that seen in other examples. This shows that there is a large diversity within classical novae and implies that nova explosions alone cannot explain the amount of lithium seen in the current Universe.
This is an important result for understanding both the explosion mechanism of classical novae and the overall chemical evolution of the Universe.
In the modern world, lithium is used in the rechargeable batteries powering smartphones and other devices. It was thought that most of the lithium found on Earth, and the rest of the Universe, was originally produced in classical nova explosions.
Observations of the classical nova V339 Del using the Subaru Telescope supported this theory, providing the first observational evidence of large amounts of lithium being produced and ejected into space (Classical Nova Explosions are Major Lithium Factories in the Universe on February 18, 2015).
Now, a team led by Akira Arai, a researcher at Koyama Astronomical Observatory of Kyoto Sangyo University, used the Subaru Telescope's open-use observation program to study V5669 Sgr, a classical nova that appeared in Sagittarius in 2015. This was only the eighth time this type of study has been successfully conducted. Four of those eight, including the first, were conducted using the Subaru Telescope.
This time is remarkable because the estimated lithium production is only a few percent of the production seen in the others. This indicates that there is a large diversity in novae. The fact that some novae produce only a small amount of lithium suggests that other objects, such as supernovae, may make important contributions to lithium production in the Universe.
We found a new type of stellar explosion that could explain a 13-billion-year-old mystery of the Milky Way’s elements
https://theconversation.com/we-found-a-n...nts-163986
INTRO: Until recently it was thought neutron star mergers were the only way heavy elements (heavier than Zinc) could be produced. These mergers involve the mashup of the remnants of two massive stars in a binary system.
But we know heavy elements were first produced not long after the Big Bang, when the universe was really young. Back then, not enough time had passed for neutron star mergers to have even occurred. Thus, another source was needed to explain the presence of early heavy elements in the Milky Way.
The discovery of an ancient star SMSS J2003-1142 in the Milky Way’s halo — which is the roughly spherical region that surrounds the galaxy — is providing the first evidence for another source for heavy elements, including uranium and possibly gold.
In our research published today in Nature, we show the heavy elements detected in SMSS J2003-1142 were likely produced, not by a neutron star merger, but through the collapse and explosion of a rapidly spinning star with a strong magnetic field and a mass about 25 times that of the Sun.
We call this explosion event a “magnetorotational hypernova”... (MORE)
