# Tag Info

14

None of those stars can go supernova, so the question is rather moot. If you look at the classifications, the most luminous is Sirius A (an A sequence star even) you can get an idea of its mass. If you look at your source page, and link to the explanation you see that A stars range from 1.4 to 2.1 stellar masses. In order to go supernova though, you need ...

12

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 ...

10

It's a matter of size and stellar evolution. There are many, many types of stellar explosions. The University of Arizona has one page that describes these types. generally, a Novs is not what we think of (i.e. a star exploding). That's actually a Type II Supernova. According to that site: Novae are frequently (perhaps always) members of binary ...

9

Your question is a bit oversimplified because there are many types of supernovae based on the size and configuration of the star. But I can answer your question about "why iron" by considering what keeps a star from exploding in the first place. In the simplest terms of star formation, when material from an interstellar nebula starts to collapse under its ...

9

The "iron core" in a supernova is actually the end product of a nuclear statistical equilibrium that begins when the silicon core begins to fuse with alpha particles (helium nuclei). Exothermic reactions are possible right up to Nickel-62 (which is actually the nucleus with the highest binding energy per nucleon). In fact, successive, rapid alpha captures ...

8

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 ...

6

As you say, SN 1572 is not very bright in the optical. There are some Hα regions that have been observed with world-class optical telescopes, but they do not look like the X-ray and infrared images that you normally see. In fact, images from the Palomar Optical Sky Survey 2 (with a limiting magnitude of ~22) do not reveal any nebular emission from ...

6

Given the description, that light patch was probably Pleiades. It is a star cluster in the constellation of Taurus which is inspired from a popular Greek mythology of Seven Sisters. You can read more about it here. EDIT: One of the great softwares, free and open source, for amateur level observational astronomy, though professionals use it as frequently ...

6

The Sun does not have nearly enough mass to become a supernova. Instead, it will swell to become a red giant, enveloping Mercury, Venus, and possibly Earth. After that, it will shed its outer layers as a planetary nebula, and settle down to become a white dwarf. Wikipedia, apparently, says the exact same things I had though of: The Sun does not have ...

6

As HDE 226868 noted in his answer, the Sun is not going to go supernova. That's something only large stars experience at the end of their main sequence life. Our Sun is a dwarf star. It's not big enough to do that. It will instead expand to be a red giant when it burns out the hydrogen at the very core of the Sun. It will continue burning hydrogen as a red ...

5

The current supernova is a supernova of type Ia. Supernovae of type Ia are used as standard candles for distance estimates, especially used to determine the Hubble constant. Hence by a better calibration of this kind of supernovae, more about the reliability and accuracy of distance estimates can be learned. The expansion rate (in relation to the distance) ...

5

It does not appear to be practical to photograph with amateur equipment. According to the Wikipedia article the remnant was viewed visually with Palomar telescope. Links to studies of the remnants were done using 2m + telescopes. So trying to get a visible light photo would require an extremely large telescope. This table does not list a magnitude for ...

5

This is going to be a short answer, but it should help. From Wikipedia: Images taken with the Spitzer Space Telescope uncovered a cloud of hot dust in the vicinity of the Pillars of Creation that one group interpreted to be a shock wave produced by a supernova. The appearance of the cloud suggests a supernova would have destroyed it 6000 years ago. ...

5

The answer is: frequently. There are many amateur astronomers that make it their ambition to discover new supernovae or to observe and report on new variable stars. As an example, let me cite amateurs Robert Evans, who apparently holds the record for most supernovae found by visual observation, or Tom Boles, who holds the record for supernova discoveries by ...

5

The speed of the blast front depends on the initial energy release and the density of the medium into which it is expanding, see here. Theory suggests and measurements confirm expansion rates of the order of thousands of km/s or a few $\times 10^6\ \mbox{m/s}$ or $\sim 1\% \mbox{c}$.

5

Yes, but it's slow. (I'm not an expert, so feel free to correct if I miss something important), but once the star is into the later stages, past the Helium stage, up to Iron, fusion mostly takes place by fusing a helium onto a heavier element, raising each atomic number by 2. That's not the only method but it's the most common. Iron can also fuse into ...

4

The paper "Frequency of nearby supernovae and climatic and biological catastrophes" by Clark, McCrea, and Stephenson published in Nature estimates (at 50% probability) that the Solar System passes within 10 parsecs of a supernova every 100 million years. This supernova would be part of a 20-parsec strip in which an estimated 50 supernovae occur. They do ...

4

According to this website the peak visible magnitude will be about 10.5 around February 2nd. Earlier estimates had been a little brighter around the same date.

4

The binding energy per nucleon is among the highest for iron-56. Therefore nuclear fusion as well as fission/photodisintegration of iron-56 consumes energy. Heat production is needed to prevent a star from collapsing to a much denser state. Iron-56 provides no way to produce heat by nuclear reactions. Hence core collapse is unavoidable. If the star isn't ...

3

The answer is that in a pre-supernova star, most of its mass is still in the form of hydrogen and helium. It is only the central core where the primordial H and He has fused to heavier elements. This picture of onion layers is typically what you see in elementary text books. It is completely misleading in a quantitative sense. It schematically represents ...

3

I see two real questions here. First, whether it's possible to have a black dwarf with a companion object. For a given black dwarf, this is unlikely, since the orbits would likely be unstable at the time scale required to produce a black dwarf. Given the size of the universe, however, it's not out of the question. A black dwarf could even capture a companion ...

3

It's very likely, that we don't have discovered every non man-made element. For some elements there exist only very short-lived isotopes. Plutonium... is the heaviest primordial element by virtue of its most stable isotope, plutonium-244, whose half-life of about 80 million years is just long enough for the element to be found in trace quantities in ...

3

Regarding Terminology: 'Mass ejections' (at least semantically) are very different from supernovae. A "mass ejection" would generally refer to something like what the sun does as part of its normal activity --- ejecting very small amounts of plasma, or on the other end of the spectrum, the ejection of massive shells of material by very massive (e.g. \$M ...

2

A hypernova is just a really, really big supernova. UMass has a (tacky designed) web page that explains it. A hypernova explosion typically has a mechanical energy output of ~ 10^53 ergs, or about a factor of 100 greater than a supernova. Regarding aftereffect, the page says this: The age of the hypernova remnant NGC5471B is about 30 thousand ...

2

There are two faintly visible areas of nebulosity on the above image taken from the Palomar Sky Survey, that correlate with the remnants of Supernova 1572. Sidney van den Bergh imaged this object in 1970 with the Palomar 200 inch telescope, comparing this with similar images taken by Walter Baade in 1949, 1955 and 1957. His findings were published in the ...

2

Not that easy way. Only stars heavy enough will undergo a supernova explosion. The majority of stars is too light. The lifetime of a star is mostly determined by its mass. In some cases (supernova type Ia) a companion star provides mass to white dwarf, which originally has been too light to explode as a supernova. Hence your technique can only work, if it ...

2

For a star to become a nova, it needs to have a mass at least 8 times greater than our sun. For a supernova, it needs to be larger. The first stage is the hydrogen fusion into heavier elements. The energy created pushes the hydrogen outwards. If there was no fusion, the star would be a low smaller. When the hydrogen fusion in the core slows down (due to a ...

2

You were so close! The answer was actually given lower down on the Wikipedia page: roughly 20 parsecs. Since one parsec is about 3.26 light-years, we can calculate that that comes out to about 64 light-years, as this seems to corroborate. The outer layers of the remnant are expanding outward at an outrageous rate - 11 million miles per hour, according to ...

Only top voted, non community-wiki answers of a minimum length are eligible