Post by Andrei Tchentchik on Aug 20, 2020 18:30:42 GMT 2
(.#490).- Betelgeuse: its luminosity starts to rise again.
Betelgeuse: its luminosity starts to rise again.
Nathalie Mayer, Journalist
Published on 02/21/2020
While the brightness of Betelgeuse has been decreasing for several weeks, now it is starting to rise again. A suprise ? Not quite. Because the red supergiant is a variable star. And it seems that having reached the bottom of its main cycle of 430 days, it is now gradually regaining its splendor.
According to the latest reports from the American Association of Variable Star Observers, the brightness of Betelgeuse has been slowly increasing since a few days. As a reminder, the supergiant red among the brightest of our starry sky had lost much of its luster in recent months. A phenomenon visible to the naked eye since its brightness was, there is very little, more than 35% that we usually know. And some already imagined that Betelgeuse would soon appear to us as a magnificent supernova.
The minimum brightness reached
This February 19, however, the Betelgeuse luminosity curve seems to have reached a minimum. Before you start to reverse. The luminosity of the red supergiant has today risen to 38% of that which it traditionally displays. And its magnitude is given at 1.55, or 0.06 magnitude above its average measured over the previous five nights.
A situation that will no doubt disappoint those who hoped to be the next witnesses to the explosion in Betelgeuse supernova. An exceptional event on the scale of a human life. There would only be three supernova explosions per century in our Milky Way. But the inversion of the luminosity curve of the red supergiant now directs astronomers towards a much less exciting track.
The end of a 430-day cycle
The hypothesis had already been mentioned by Edward Guinan, a researcher at the University of Villanova (United States), in a Telegram from the Astronomer a few days ago. Betelgeuse would simply have been caught in a kind of pulsation much deeper than usual. Because remember that the red supergiant has long been known to be part of what astronomers call a variable star.
Its luminosity evolves over time according to several interlocking cycles. But a dominant cycle - probably linked to a kind of pulsation from the star - stands out. A 430-day cycle observed since the 1930s. A cycle that suggested to researchers that Betelgeuse could naturally reach a minimum of light this February 21, 2020, after a precision of more or less 7 days.
Yet the mystery remains. First because it will take a few days to see if the new trend is confirmed. Then, because even by following its 430-day cycle, Betelgeuse should not have reached a brightness below 0.9 magnitude. So perhaps we are witnessing the coincidence of the minima of two cycles of the red supergiant. According to Edward Guinan, questioned by our colleagues from Forbes, the images of the red supergiant released recently by the ESO team could also be the result of a particularly deep pulse of Betelgeuse, responsible for a darkening of the southern hemisphere of the star.
Case still to follow ...
WHAT YOU MUST REMEMBER
• For several months, the brightness of Betelgeuse has been decreasing.
• Today, she seems to want to start rising again.
• Behavior that would exclude the possibility of a supernova explosion.
• But which could (almost) be explained by the natural cycles of variation of luminosity of this variable star.
TO KNOW MORE
Betelgeuse: we will soon know if it will explode as a supernova
The brightness of Betelgeuse seems to want to continue to decrease. But some astronomers have announced that it may well go up in the next few days. If this were not to be the case, we should perhaps expect a forthcoming supernova explosion. And to find out how "next," astronomers could start monitoring neutrino fluxes from space.
Article by Nathalie Mayer
Published on 02/15/2020
For several months now, astronomers, whether amateur or professional, have been watching Betelgeuse, this red supergiant which forms Orion's right shoulder. Because its radiance has diminished dramatically. Edward Guinan is an astronomer at the University of Villanova (United States). He has been studying stars by photometry for 25 years. And he testifies online that Betelgeuse currently appears less bright than he has ever observed.
The magnitude of Betelgeuse would today be comparable to that of its "neighbor" Bellatrix, which forms the other shoulder of Orion. It would therefore be around 1.7. But with the naked eye, the comparison between the two stars is perilous. Because Betelgeuse appears red-orange while Bellatrix appears white-blue. And as we age, we see the world through a sort of filter. What continue to assess Betelgeuse as (much) brighter than Bellatrix when objective measurements prove the opposite. On February 10, 2020, according to measurements made by the American Association of Variable Star Observers (AAVSO), the magnitude of Betelgeuse was 1.65.
Betelgeuse traditionally appeared in 10th position on the list of the brightest stars in our sky. She was demoted to 23rd position. © ESO
"
Something unusual is undoubtedly going on.
If the AAVSO is interested in Betelgeuse, it is because it is a known variable star. Its luminosity varies according to several complex cycles. But to believe Edward Guinan, according to a dominant cycle of 430 days. What to think that the red supergiant could reach a minimum of brightness on February 21. A given date with a margin of error of more or less 7 days. Beyond that, its luminosity would naturally rise again. Some also claim to have already observed it. Confirming this hypothesis of a rather classic brightness variation also favored by Sylvie Vauclair on Futura, a few days ago. Even if, for Edward Guinan, the mystery would remain whole, because the brightness of Betelgeuse, at the lowest of its cycle, generally does not exceed a magnitude of the order of 0.9. “Something unusual is undoubtedly underway. "
So perhaps the beginnings of an imminent explosion in a supernova of the red supergiant. The brilliance of Betelgeuse could then rival that of the Full Moon. Even make it visible in broad daylight.
The Betelgeuse Nanny
@betelgeusenanny
#Betelgeuse Trend of Daily Means, Visual Magnitude, Last 25 Days. Observations from @aavso
10:27 - Feb 9 2020
F I N .
Betelgeuse: its luminosity starts to rise again.
Nathalie Mayer, Journalist
Published on 02/21/2020
While the brightness of Betelgeuse has been decreasing for several weeks, now it is starting to rise again. A suprise ? Not quite. Because the red supergiant is a variable star. And it seems that having reached the bottom of its main cycle of 430 days, it is now gradually regaining its splendor.
According to the latest reports from the American Association of Variable Star Observers, the brightness of Betelgeuse has been slowly increasing since a few days. As a reminder, the supergiant red among the brightest of our starry sky had lost much of its luster in recent months. A phenomenon visible to the naked eye since its brightness was, there is very little, more than 35% that we usually know. And some already imagined that Betelgeuse would soon appear to us as a magnificent supernova.
The minimum brightness reached
This February 19, however, the Betelgeuse luminosity curve seems to have reached a minimum. Before you start to reverse. The luminosity of the red supergiant has today risen to 38% of that which it traditionally displays. And its magnitude is given at 1.55, or 0.06 magnitude above its average measured over the previous five nights.
A situation that will no doubt disappoint those who hoped to be the next witnesses to the explosion in Betelgeuse supernova. An exceptional event on the scale of a human life. There would only be three supernova explosions per century in our Milky Way. But the inversion of the luminosity curve of the red supergiant now directs astronomers towards a much less exciting track.
The end of a 430-day cycle
The hypothesis had already been mentioned by Edward Guinan, a researcher at the University of Villanova (United States), in a Telegram from the Astronomer a few days ago. Betelgeuse would simply have been caught in a kind of pulsation much deeper than usual. Because remember that the red supergiant has long been known to be part of what astronomers call a variable star.
Its luminosity evolves over time according to several interlocking cycles. But a dominant cycle - probably linked to a kind of pulsation from the star - stands out. A 430-day cycle observed since the 1930s. A cycle that suggested to researchers that Betelgeuse could naturally reach a minimum of light this February 21, 2020, after a precision of more or less 7 days.
Yet the mystery remains. First because it will take a few days to see if the new trend is confirmed. Then, because even by following its 430-day cycle, Betelgeuse should not have reached a brightness below 0.9 magnitude. So perhaps we are witnessing the coincidence of the minima of two cycles of the red supergiant. According to Edward Guinan, questioned by our colleagues from Forbes, the images of the red supergiant released recently by the ESO team could also be the result of a particularly deep pulse of Betelgeuse, responsible for a darkening of the southern hemisphere of the star.
Case still to follow ...
WHAT YOU MUST REMEMBER
• For several months, the brightness of Betelgeuse has been decreasing.
• Today, she seems to want to start rising again.
• Behavior that would exclude the possibility of a supernova explosion.
• But which could (almost) be explained by the natural cycles of variation of luminosity of this variable star.
TO KNOW MORE
Betelgeuse: we will soon know if it will explode as a supernova
The brightness of Betelgeuse seems to want to continue to decrease. But some astronomers have announced that it may well go up in the next few days. If this were not to be the case, we should perhaps expect a forthcoming supernova explosion. And to find out how "next," astronomers could start monitoring neutrino fluxes from space.
Article by Nathalie Mayer
Published on 02/15/2020
For several months now, astronomers, whether amateur or professional, have been watching Betelgeuse, this red supergiant which forms Orion's right shoulder. Because its radiance has diminished dramatically. Edward Guinan is an astronomer at the University of Villanova (United States). He has been studying stars by photometry for 25 years. And he testifies online that Betelgeuse currently appears less bright than he has ever observed.
The magnitude of Betelgeuse would today be comparable to that of its "neighbor" Bellatrix, which forms the other shoulder of Orion. It would therefore be around 1.7. But with the naked eye, the comparison between the two stars is perilous. Because Betelgeuse appears red-orange while Bellatrix appears white-blue. And as we age, we see the world through a sort of filter. What continue to assess Betelgeuse as (much) brighter than Bellatrix when objective measurements prove the opposite. On February 10, 2020, according to measurements made by the American Association of Variable Star Observers (AAVSO), the magnitude of Betelgeuse was 1.65.
Betelgeuse traditionally appeared in 10th position on the list of the brightest stars in our sky. She was demoted to 23rd position. © ESO
"
Something unusual is undoubtedly going on.
If the AAVSO is interested in Betelgeuse, it is because it is a known variable star. Its luminosity varies according to several complex cycles. But to believe Edward Guinan, according to a dominant cycle of 430 days. What to think that the red supergiant could reach a minimum of brightness on February 21. A given date with a margin of error of more or less 7 days. Beyond that, its luminosity would naturally rise again. Some also claim to have already observed it. Confirming this hypothesis of a rather classic brightness variation also favored by Sylvie Vauclair on Futura, a few days ago. Even if, for Edward Guinan, the mystery would remain whole, because the brightness of Betelgeuse, at the lowest of its cycle, generally does not exceed a magnitude of the order of 0.9. “Something unusual is undoubtedly underway. "
So perhaps the beginnings of an imminent explosion in a supernova of the red supergiant. The brilliance of Betelgeuse could then rival that of the Full Moon. Even make it visible in broad daylight.
The Betelgeuse Nanny
@betelgeusenanny
#Betelgeuse Trend of Daily Means, Visual Magnitude, Last 25 Days. Observations from @aavso
10:27 - Feb 9 2020
F I N .
