Post by Andrei Tchentchik on Aug 20, 2020 18:29:42 GMT 2
(.#489).- Neutrinos as whistleblowers, the Betelgeuse star.
Neutrinos as whistleblowers.
Recall that the simple fact of seeing it classified in the category of red supergiants indicates to us that the nucleus of Betelgeuse has already burned its hydrogen and even its helium. Because it is with the transition between the combustion of helium and that of carbon that the temperature of a star increases sharply. And with it, the radiation pressure and the diameter of the star. Located at the heart of the Solar System, Betelgeuse would have already devoured the planet Mars.
Universal-Sci
@universal_sci
Astonishing: Betelgeuse in comparison to our solar system.
It is so incredibly immense that if swapped with our Sun it would engulf the orbit of Mars!
Credit: ESO / L. Calçada
Note also that the complete combustion of carbon takes some 100,000 years. The combustion of the following elements is then very rapid: a few years for neon, a few months for oxygen, a day or two for silicon. All taking place without observable change in the photosphere of the star. As it inexorably approaches its gravitational collapse and its transformation into a supernova.
But neutrinos could play the role of launchers warning of an impending explosion. In fact, during the carbon combustion phase, the neutrinos emitted have a typical energy signature. And as it evolves until the heart collapses, the energy flow as well as the energy per neutrino increases. According to a study carried out a few years ago, in the last hours of a star's life, the neutrinos produced even cross a critical energy threshold observable from Earth.
In this image, several neutrino detection events such as those that could be used to alert the impending explosion of a star in a supernova. © Super-Kamiokande
It is more precisely the interaction between the antineutrinos coming from the dying star and the protons of the detector which could be revealing. Conventionally, this type of interaction is rare. But if a star close enough to us was burning its silicon, it could produce antineutrinos sufficiently energetic for our current detectors to keep track of it.
Calculations show that Super-Kamiokande, and its 50,000 tonnes of water, should be able to register, within the first hour, some 60 to 70 antineutrinos from a Betelgeuse which has started to burn its silicon. And some 1,600 in total during the day. The fact that these antineutrinos are supposed to arrive on Earth in packets - corresponding to the oscillations of the heart and the envelope of the star -, this could give a strong indication that Betelgeuse is about to explode. And offer all observatories around the world a unique opportunity to observe the phenomenon!
Taken by Alma, it is the best image ever made of Betelgeuse. © ES
F I N .
Neutrinos as whistleblowers.
Recall that the simple fact of seeing it classified in the category of red supergiants indicates to us that the nucleus of Betelgeuse has already burned its hydrogen and even its helium. Because it is with the transition between the combustion of helium and that of carbon that the temperature of a star increases sharply. And with it, the radiation pressure and the diameter of the star. Located at the heart of the Solar System, Betelgeuse would have already devoured the planet Mars.
Universal-Sci
@universal_sci
Astonishing: Betelgeuse in comparison to our solar system.
It is so incredibly immense that if swapped with our Sun it would engulf the orbit of Mars!
Credit: ESO / L. Calçada
Note also that the complete combustion of carbon takes some 100,000 years. The combustion of the following elements is then very rapid: a few years for neon, a few months for oxygen, a day or two for silicon. All taking place without observable change in the photosphere of the star. As it inexorably approaches its gravitational collapse and its transformation into a supernova.
But neutrinos could play the role of launchers warning of an impending explosion. In fact, during the carbon combustion phase, the neutrinos emitted have a typical energy signature. And as it evolves until the heart collapses, the energy flow as well as the energy per neutrino increases. According to a study carried out a few years ago, in the last hours of a star's life, the neutrinos produced even cross a critical energy threshold observable from Earth.
In this image, several neutrino detection events such as those that could be used to alert the impending explosion of a star in a supernova. © Super-Kamiokande
It is more precisely the interaction between the antineutrinos coming from the dying star and the protons of the detector which could be revealing. Conventionally, this type of interaction is rare. But if a star close enough to us was burning its silicon, it could produce antineutrinos sufficiently energetic for our current detectors to keep track of it.
Calculations show that Super-Kamiokande, and its 50,000 tonnes of water, should be able to register, within the first hour, some 60 to 70 antineutrinos from a Betelgeuse which has started to burn its silicon. And some 1,600 in total during the day. The fact that these antineutrinos are supposed to arrive on Earth in packets - corresponding to the oscillations of the heart and the envelope of the star -, this could give a strong indication that Betelgeuse is about to explode. And offer all observatories around the world a unique opportunity to observe the phenomenon!
Taken by Alma, it is the best image ever made of Betelgeuse. © ES
F I N .
