# Tag Info

## New answers tagged star

0

Supernova create huge spikes in neutrino emissions. Since neutrinos pass through a stellar mass mostly unimpeded, they're visible up to 3 hours before the shockwave even starts to affect the star's surface. Since neutrinos travel at the speed of light, they will always keep their 3 hour head start. Thus, unless you have a neutrino detector buried a few ...

0

Well, there might be. I strongly disagree with your statement that circumstellar discs are what differentiate B(e) stars from other related stars. In fact, there are four primary criteria for stars that satisfy "the B(e) phenomenon": Strong emission lines in the Balmer series Emission of lines of certain (low ionization) metals such as Fe II "Forbidden ...

9

Naked eye nova are fairly common, several per year. Here's one. Naked eye supernova are far rarer. SN1987a in the large Magellanic cloud was naked eye visible (vid). From this list, it appears the supernova in 1987 was the most recent naked eye supernova. There was a naked eye gamma ray burst in 2008, but I don't think anyone actually got outside in time to ...

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If you remember the Stefan-Boltzmann law, you know that luminosity $L$ scales with $T^4$, $L=\sigma A T^4$. Thus, the star will move to higher temperatures and higher luminosities i.e. upwards to the left.

4

I assume by largest, you mean largest radius. Well it won't be VV Cep B since this is merely a B-type main sequence star. O-type main sequence stars are known and these have both larger masses and larger radii on the main sequence (when they are burning hydrogen in their cores). A selection of the most massive objects can be found in the R136 star forming ...

2

One of the absolutely fundamental differences between the LMC and SMC, and why they have become among the most studied of astronomical objects, is their metallicity. The average metallicity of interstellar gas in the LMC is about half that of the Sun, whereas the average metallicity in the SMC is only a fifth that of the Sun. Hence the clouds act as two ...

0

If you put a large enough mass of earth-like rock together, you might get lithium fusion. Stars fuse what little lithium they have at masses just under the mass needed to become a red dwarf ("stars" that only burn lithium and not hydrogen are large mass brown dwarf stars). But the lithium concentration in a "rock" star (hur, hur. Rock star) is certainly ...

2

You would/should be able to detect the annihilation of electron-positron pairs at the boundary between normal-matter and anti-matter space. This has a distinctive energy and so could be identified unambiguously. For an example of the detection of electron-positron annihilation see this NASA news item.

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There are two major points about this, I think. First, and ultimately most importantly, is that if we have matter here, and they have antimatter over there, then somewhere in between we must have a region that transitions from matter to antimatter. Even if this region is located in the intergalactic medium, where densities are typically very low, ...

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Assuming the parent star of such a system emits a solar wind similar to our sun's, then those antimatter particles would collide at that system's heliopause with regular-matter cosmic ray particles. I would think such a matter-antimatter reaction would be visible across much of the galaxy.

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Although sources go way back, the current best estimate seems to be that of Abdul Ahad from March 2004: For an observer located anywhere within the Solar System - excluding the contribution of light from the Sun (Solar constant) - provisional integrations using stellar magnitude data sourced from astronomical catalogs places an an approximation for ...

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