Supernova Detonation Aimed at Earth? Astronomers Say "Maybe"

[Jon Miller]

If it takes you 5 hours to read a review paper in your field (or close to your field), that is a lot better than me.

JM

[KrazyHorse]

Don't read too well, hmmm?

Bug up your ass, hmmmm? You realize that the mass of the star wasn't in the original article, right?

Jwr = Ewr/d²/2s = 1.2e19s·Jsol/(7k·63k)²/2s for d in AU to compare to solar radiation reaching earth.
Jwr = 6e18·Jsol/(441e6)² = 30.8 Jsol = 30.8·1400W/m² radiation reaching earth

You're missing a factor of 4. The solid angle scales with pi*r_earth^2/(4*pi*d^2).

And I did say order of magnitude.

The only problem I have with this calculation is that emissions are not necessarily symmetric. If the star has high angular momentum much of the emitted energy can be collimated into a pair of jets emitted near the poles (GRB). If this is the case and one of these jets happened to be aligned with the Earth (possible, given that we're 16 degrees off the axis of rotation of the object) then we might see a flux hundreds of times bigger than the naive isotropic emission calculation would predict. Now, I know little enough about astronomy that I refuse to speculate on either the probability of this object going GRB on us OR the probability distribution of jets relative to the axis of rotation (assuming anybody knows either of these things, which is AFAIK doubtful because GRBs are just beginning to be understood at all).

Also, you should have noticed that the mass of this star had to be much larger than the mass of the sun because the article itself mentioned that the energy release would be higher than msun * c^2

[KrazyHorse]

If it takes you 5 hours to read a review paper in your field (or close to your field), that is a lot better than me.

JM

This is the second review article I've read on Little Higgs in the last week, so I'm beginning to be familiar with a lot of the material. The first one I read was by Schmaltz and was the accompaniment to his 2005(?) TASI lectures.

[KrazyHorse]

That one took me ~30 hours. I spent an entire day last week understanding one 5 page piece of it.

[Jon Miller]

That is about my usual for a theory paper in my area of nuclear physics.

Of course, I spend most of my time doing non-theory.

JM

[Ramo]

The only problem I have with this calculation is that emissions are not necessarily symmetric. If the star has high angular momentum much of the emitted energy can be collimated into a pair of jets emitted near the poles (GRB). If this is the case and one of these jets happened to be aligned with the Earth (possible, given that we're 16 degrees off the axis of rotation of the object) then we might see a flux hundreds of times bigger than the naive isotropic emission calculation would predict. Now, I know little enough about astronomy that I refuse to speculate on either the probability of this object going GRB on us OR the probability distribution of jets relative to the axis of rotation (assuming anybody knows either of these things, which is AFAIK doubtful because GRBs are just beginning to be understood at all).

Also, you should have noticed that the mass of this star had to be much larger than the mass of the sun because the article itself mentioned that the energy release would be higher than msun * c^2

Yeah, but it didn't specify by how much. "More" could be a factor of two.

And obviously there would be multiple scaling factors thrown in. And there would probably be some issues with resonance.

My "calculation" was meant to be flippant. I was pointing out the crappiness of the article (the language about a large mc^2).

[KrazyHorse]

I know it was a ****ty article, dude. And ignore Straybow's *****y-ass response.

I'm just refining your estimates somewhat. And will point out that a flux of ionizing radiation is not the same as a flux composed mainly of visible, IR and UV light

[Docfeelgood]

If the flux capacitor is tuned with a transsexual drive then we could have a barium borehole full of PMS waves that will cause an envelope of nutreenie particles for protection.

Hey, I'v watched Star Trek too!

[Ramo]

I know it was a ****ty article, dude. And ignore Straybow's *****y-ass response.

I'm just refining your estimates somewhat. And will point out that a flux of ionizing radiation is not the same as a flux composed mainly of visible, IR and UV light

True.

[Straybow]

[Q=Ramo;5571907]

Don't read too well, hmmm?

Bug up your ass, hmmmm? You realize that the mass of the star wasn't in the original article, right?[/q] Sorry I didn't realize you'd never before or since read any other articles on supernovae. Carry on.

Jwr = Ewr/d²/2s = 1.2e19s·Jsol/(7k·63k)²/2s for d in AU to compare to solar radiation reaching earth.
Jwr = 6e18·Jsol/(441e6)² = 30.8 Jsol = 30.8·1400W/m² radiation reaching earth

You're missing a factor of 4. The solid angle scales with pi*r_earth^2/(4*pi*d^2).

And I did say order of magnitude.

The factor of 4 for solid angles drops out if you are comparing the solid angle from WR104 and the solid angle from the sun, so your math is bad. Besides, you're again showing your lack of reading skillz. I wasn't comparing the solid angles, I was comparing the incident density, which is still 1/d².

What I didn't do was assume that Earth was in the center of the radiation beam, and just used the simple 1/d² as though the radiation were spherical. If we aren't in the center of the beam it will likely be less than the spherical calculation because the drop-off is very steep. If the beam coincides with the axis of the binary system, at 16° off-axis we'll do well to detect them on the surface.

[Straybow]

[Q=Ramo;5571915]BTW, since you're on a reading kick, the article said two minutes, not seconds.[/Q] Glad I could make you feel better.

Meh, that makes it 0.5 times average solar radiation. Kinda accentuates the point that the effect may be mild from that distance.

[Ramo]

You haven't provided a justification that an anisotropy would produce precisely a factor of 4. Given your pedantic wankery, that's a bizarre position to take.

Sorry I didn't realize you'd never before or since read any other articles on supernovae. Carry on.

Yes. I don't have the same interest in miscellaneous stars that you do. That makes me a terrible human being.

[Ramo]

The factor of 4 for solid angles drops out if you are comparing the solid angle from WR104 and the solid angle from the sun, so your math is bad.

What I didn't do was assume that Earth was in the center of the radiation beam, and just used the simple 1/d² as though the radiation were spherical.

What? You realize that these two sentences are contradictory, right?

[chequita guevara]

I know it was a ****ty article, [Ramo].

It was, which is why I immediately googled Wolf-Rayet 104, and found out that it was twenty solar masses, give or take. And I got to learn about Wolf-Rayet stars, GRBs, and cosmic rays.

Apolyton makes me smarter

Shut up, Kitty.

[KrazyHorse]

?

WTF?

Was that a preemptive strike? I've been utterly pleasant in this thread. Despite the fact that there are a number of openings here to engage in a little gratuitous snarkiness.