Betelgeuse Supernova can go BOOM at any time

[onemd]

I notice everyone seems to say Betelgeuse once it explodes will be 3rd brightest before the moon, and the sun. But everyone seems to miss a key component in history in regards to SN 1006 and the explosion in the year 1006 AD. It's about 7200 light years away, and when it exploded as a supernova, it was nearly as bright as the moon.

So if that was nearly as bright as the moon. How can Betelgeuse be just as bright? Its nearly 6600 light years closer to us. And further more we aren't completely sure how close it is, it can be between 400-700 light years away, but seems the consensus on about 600 light years away approximately.

Lets pretend each 100 light years = 1 inch. Draw out 72 inches as the radius, and imagine that as a sphere.
Now imagine another one, draw it out as 6 inches. And imagine that as a sphere. The volume difference between the two is quite massive.

The Inverse Square Law
https://www.e-education.psu.edu/astro801/content/l4_p4.html

Wolframalpha
((3.9 * 10^26 W)) / (4 π (1.5 * 10^11 m)^2)

This equates a normal amount that the earth receives from the sun is 1379 W/m^2 (watts per square meter)


So lets plug in the following numbers:
A supernova can output 10^44 joules - (Assuming Betelgeuse is 640 light years = 6.055e+18 M)
((3.9 * 10^44 W)) / (And the distance between earth and Betelgeuse: ~6 * 10^18 m)^2)

Wolframalpha
((3.9 * 10^44 W)) / (4 π (6 * 10^18 m)^2)

Yields a result of: 862,089 W/m^2 (watts per square meter)
That means the energy received by the surface of Earth will be ~800-1000X as much as from the sun.



So again, why does everyone seem to acknowledge if Betelgeuse goes supernova it being dimmer then the moon, when the one over 7000 light years in the year 1006 was almost as bright as the moon?

To get an idea on how large Betelgeuse is, watch: https://www.youtube.com/watch?v=GoW8Tf7hTGA&t=10s - Watch from 0 to 2 Min 45 seconds to get an idea


Betelgeuse Magnitude:



https://www.newscientist.com/article/dn17282-betelgeuse-the-incredible-shrinking-star/ - "But a new study suggests the giant star has been shrinking for more than a decade. Betelgeuse is nearing the end of its life as a red supergiant. The bright, bloated star is 15 to 20 times more massive than the sun. ... New observations indicate the giant star has shrunk by more than 15 per cent since 1993"

[BADecker]

I like your part about: "And further more we aren't completely sure how close it is, it can be between 400-700 light years away, but seems the consensus on about 600 light years away approximately."

If we have a good guess that a star is 600 l-y away, but maintain that guess only by consensus, do we really know anything about the star?

Is it a fact that Betelgeuse shrunk by "more than 15 per cent since 1993?" Or are our observations showing us something that we don't really know anything about? That's 400 to 700 l-y away.

Why does science think that they know what is really happening out there, especially since the light took 400 to 700 years to get here? It's all a guessing game.

[onemd]

72 Meters = The star explosion in the year 1006
6 Meters = Betelgeuse.

[Artemis3]

I notice everyone seems to say Betelgeuse once it explodes will be 3rd brightest before the moon, and the sun. But everyone seems to miss a key component in history in regards to SN 1006 and the explosion in the year 1006 AD. It's about 7200 light years away, and when it exploded as a supernova, it was nearly as bright as the moon.

So if that was nearly as bright as the moon. How can Betelgeuse be just as bright? Its nearly 6600 light years closer to us. And further more we aren't completely sure how close it is, it can be between 400-700 light years away, but seems the consensus on about 600 light years away approximately.

You say "at any time", but are you aware that what you see is as old as that number you mention the distance is? It is 6600 years late...

More importantly is how long would it last, as that would mean nice lightning at night, perhaps people could turn off the lights or something. Fauna might be troubled, but nothing can be done. I doubt I'll be a second sun, more like an additional larger moon.

Did you know how long that SN 1006 lasted? 3 months. Make those months count!

Then again it might be a while since we finally get to see this ancient history that is the sky.

Remember, even the Sun light is 8 minutes old (and they say it takes thousands of years to reach the surface). Light Years mean exactly that, time for light it takes to reach in Earth years.

[LoyceMobile]

So lets plug in the following numbers:
A supernova can output 10^44 joules - (Assuming Betelgeuse is 640 light years = 6.055e+18 M)
((3.9 * 10^44 W)) / (And the distance between earth and Betelgeuse: ~6 * 10^18 m)^2)

Wolframalpha
((3.9 * 10^44 W)) / (4 π (6 * 10^18 m)^2)

Yields a result of: 862,089 W/m^2 (watts per square meter)
That means the energy received by the surface of Earth will be ~800-1000X as much as from the sun.

Why do you turn joules into watts? Are you assuming all energy is emitted in just one second?

If it's emitted in 3 months as the post above says, you'll have to divide the brightness by 86400 seconds per day and again by 90 days per 3 months.
Without checking the math, that probably puts the brightness a little less than the moon.

[onemd]

So lets plug in the following numbers:
A supernova can output 10^44 joules - (Assuming Betelgeuse is 640 light years = 6.055e+18 M)
((3.9 * 10^44 W)) / (And the distance between earth and Betelgeuse: ~6 * 10^18 m)^2)

Wolframalpha
((3.9 * 10^44 W)) / (4 π (6 * 10^18 m)^2)

Yields a result of: 862,089 W/m^2 (watts per square meter)
That means the energy received by the surface of Earth will be ~800-1000X as much as from the sun.

Why do you turn joules into watts? Are you assuming all energy is emitted in just one second?

If it's emitted in 3 months as the post above says, you'll have to divide the brightness by 86400 seconds per day and again by 90 days per 3 months.
Without checking the math, that probably puts the brightness a little less than the moon.

https://en.wikipedia.org/wiki/Type_II_supernova

A cataclysmic implosion of the core takes place within seconds. Without the support of the now-imploded inner core, the outer core collapses inwards under gravity and reaches a velocity of up to 23% of the speed of light and the sudden compression increases the temperature of the inner core to up to 100 billion kelvins. Neutrons and neutrinos are formed via reversed beta-decay, releasing about 10^46 joules (100 foe) in a ten-second burst

It's a curve, it starts out as 10^45 watts or so, for the first 10-30 seconds, then it reduces. It's the first 10-30 seconds that turns all of us into a burned crisp.







Us:

[onemd]

FYI, been dimming for over a month, and now the star radius has changed by 10%, along with the star temperature dropping 100 K. For reference, human life is about 100 years, stars are in the order of millions to billions of years. Changes take a loooooong time, and we are here for a blimp. Sudden massive changes like this, don't occur very often, and stars remain for a long time.

The fact these sudden massive changes are happening around Betelgeuse, means, it's undergoing a sudden transition.

We report further on the recent unusual dimming of the red supergiant Betelgeuse (alpha Ori) reported previously in ATel #13341 and ATel #13365.

has diminished by nearly 25%. At face value using R'/R = [(T'/T)^4 / L'/L]^0.5 (where R', T' and L' are the current values of stellar Radius, Temperature & Luminosity), this implies an increase of the star's radius of ~9%

[BADecker]

Look. Would somebody tell us if Betelgeuse went supernova 200 years ago or not? I mean, the light waves and gravity waves haven't gotten here yet. We might all be doomed already.

[googie4]

It won't go supernova anytime soon. They detected neutrinos from near that part, but not exactly Betelgeuse. And from my understanding the neutrinos are detected a couple of hours before the star goes supernova. This was days ago. It's just people getting exited for the no chance possibility.

[onemd]

It won't go supernova anytime soon. They detected neutrinos from near that part, but not exactly Betelgeuse. And from my understanding the neutrinos are detected a couple of hours before the star goes supernova. This was days ago. It's just people getting exited for the no chance possibility.

http://www.astronomerstelegram.org/?read=13410

Its been dimming for more then a month, and further observations show even more. And suggests a 9-10% radius change, along with the temperature of the star changing by 100 K. These changes are drastic for a star where changes are static over millions of years.

[onemd]

Speculation:

The below is for a 25 solar mass star, Betelgeuse is about 10 Million years old, and the numbers can vary a bit. 600 years can perhaps be 1000-2000 years, etc. Assuming 2000 years,
About 2000 years ago, Betelgeuse noted by Chinese astronomers was a different color. So speculation, Betelgeuse, changed from helium to carbon about 2000 years ago. And now, changed from carbon to oxygen. Time frame to supernova. ~1 year to 6 Months from now.

[googie4]

It won't go supernova anytime soon. They detected neutrinos from near that part, but not exactly Betelgeuse. And from my understanding the neutrinos are detected a couple of hours before the star goes supernova. This was days ago. It's just people getting exited for the no chance possibility.

http://www.astronomerstelegram.org/?read=13410

Its been dimming for more then a month, and further observations show even more. And suggests a 9-10% radius change, along with the temperature of the star changing by 100 K. These changes are drastic for a star where changes are static over millions of years.

Changes for such a star is normal and continuous. They get bigger, in terms of volume (not mass) and then get smaller.