Luminosity and neutrino questions

[K. Doc Holiday]

IK Pegasi B is considered the white dwarf most likely to supernova in our galactic neighborhood, although some professors (eg: Neil F. Cumins of Maine) thinks it might nova instead. (I agree with Professor Cumins)

Questions:
At about 150 light years distant would this faint star become visible to the unaided eye? In other words, if it goes supernova it will be brighter than a full moon but if it merely goes nova would we even notice, visually.

2nd question:
Neutrinos precede core collapse supernovae (by as much as a day) which could serve as a warning.
Is there known evidence that neutrinos precede type 1a (standard candle) supernovae? If so, when and where?
2nd part:
Have we ever recorded a neutrino burst preceding a nova event?

3rd question:
Are there any government protocols in place in the event of a nearby supernova? I just signed up to be notified in the event of a neutrino burst. Is homeland security or the defense department signed up.

My concern is the EMP from a nearby supernova might destroy all unprotected satellites and knock all the jets and helicopters out of the sky.

I love theory but really suck at researching on the internet. Thanks ahead of time for enlightening me.

 

[Vanadium 50]

It's not going to go supermova for a couple of billion years. By that time, I don't think helicopters will be a top priority, In any event, IK Pegasi would have moved by then.

 

[mfb]

I don't know about the visible light output, but I'm sure there are publications discussing that as well.

The neutrino flux would depend a lot on the mechanism, here are calculations for two options: deflagration-to-detonation and Gravitationally Confined Detonation. 150 light years would be close enough to get neutrino events in both cases.

Have we ever recorded a neutrino burst preceding a nova event?

No, SN1987A is still the only extrasolar event where neutrinos could be linked to a source.

Are there any government protocols in place in the event of a nearby supernova? I just signed up to be notified in the event of a neutrino burst. Is homeland security or the defense department signed up.

I would expect so.

A supernova, and even more a nova, has to be really close for immediate danger. There is no candidate that close to the sun that would explode in the next hundreds of years.

 

[K. Doc Holiday]

It's not going to go supermova for a couple of billion years. By that time, I don't think helicopters will be a top priority, In any event, IK Pegasi would have moved by then.

Dear Van, I appreciate your input. When you wrote "billion" did you mean million? I have read estimates for a couple million. None of them came anywhere close to the billion mark. Btw. All the articles I have read say expressly that these are estimates. None have your apparent certainty. How certain are you? Any chance at all that your estimate is inaccurate?
Sincerely
Doc

 

[K. Doc Holiday]

I don't know about the visible light output, but I'm sure there are publications discussing that as well.

The neutrino flux would depend a lot on the mechanism, here are calculations for two options: deflagration-to-detonation and Gravitationally Confined Detonation. 150 light years would be close enough to get neutrino events in both cases.
No, SN1987A is still the only extrasolar event where neutrinos could be linked to a source.
I would expect so.

A supernova, and even more a nova, has to be really close for immediate danger. There is no candidate that close to the sun that would explode in the next hundreds of years.

Dear mfb, your reply was very helpful. Thank you.

I read the articles but lack the educational background to understand them completely.
It appears both types of supernova emit neutrinos. Correct?

If there was mention of a time delay between the neutrinos and visible light I didn't catch it. Was there? SUN 1987A had a time delay of almost a day?

Finally, could your estimate of a few hundred years (the other person to comment said 2 billion) be a bit long?
In other words, what are the odds that it has already gone nova?

What are the odds the light from that nova will reach Earth on January 9th, 2017? For example.

 

[K. Doc Holiday]

I don't know about the visible light output, but I'm sure there are publications discussing that as well.

The neutrino flux would depend a lot on the mechanism, here are calculations for two options: deflagration-to-detonation and Gravitationally Confined Detonation. 150 light years would be close enough to get neutrino events in both cases.
No, SN1987A is still the only extrasolar event where neutrinos could be linked to a source.
I would expect so.

A supernova, and even more a nova, has to be really close for immediate danger. There is no candidate that close to the sun that would explode in the next hundreds of years.

Forgive me. One more question.

From what I have read everyone is guessing which white dwarfs are the progenitors for type 1a.

Since we have never seen a white dwarf before it goes supernova nobody actually knows for certain?

Everyone appears to assume the exploding mechanism is the chandrasekhar limit. Correct?

Is there any chance at all they might be wrong? Any chance at all?

I think polar white dwarfs might be the progenitors. In fact, I think AN Ursae Majoris has probably already exploded as a type 1a supernova.

Are my odds of being correct zero?

ps. I apologize for asking such stupid questions in advance and I appreciate your patience.

 

[mfb]

I read the articles but lack the educational background to understand them completely.
It appears both types of supernova emit neutrinos. Correct?

They do, but at a much lower rate than core-collapse supernovae. In 1987 the detectors found more than 10 neutrinos from a supernova 170,000 light years away, while the detectors discussed there (exististing or planned for the near future), much more sensitive than the old ones, need the supernova of type 1A to be closer than ~10,000 light years (deflagration-to-detonation) or ~1000 light years (Gravitationally Confined Detonation) for the same result.

SN 1987A had a time delay of a few hours.

Finally, could your estimate of a few hundred years (the other person to comment said 2 billion) be a bit long?

I said nothing is estimated to explode within a few hundred years. That is a lower limit, it includes processes that happen in a billion years. Astronomical times are always "as seen by Earth".

 

[snorkack]

I don't know about the visible light output, but I'm sure there are publications discussing that as well.

Easily visible.
Take the 6 brightest novae of XX century:
Nova Aquilae 1918 - -0,5, about 800 ly
Nova Persei 1901 - +0,2, about 1600 ly
Nova Puppis 1942 - +0,3, about 3700 ly
Nova Pictoris 1925 - +1,2, about 1700 ly
Nova Herculis 1934 - +1,5, about 1300 ly
Nova Cygni 1975 - +1,7, about 6400 ly

 

[Vanadium 50]

When you wrote "billion" did you mean million? ... Any chance at all that your estimate is inaccurate?

No, and no. IK Peg is a young star (100 million years, +/- about a factor of 3 in each direction) weighing about 1.6 solar masses. A 1.5 solar mass star takes about 2.2 billion years to reach the red giant phase, where you can have substantial mass transfer to the WD. At 1.6 it will go somewhat faster, but it is still well over a billion years.