<p>None of those stars <em>can</em> go supernova, so the question is rather moot.  If you look at the classifications, the most luminous is <a href="http://en.wikipedia.org/wiki/Sirius#Sirius_A">Sirius A</a> (an <a href="http://en.wikipedia.org/wiki/Stellar_classification#Class_A">A sequence</a> 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 href="http://en.wikipedia.org/wiki/A_V_star">A stars range from 1.4 to 2.1 stellar masses</a>. In order to go supernova though, <a href="http://en.wikipedia.org/wiki/Type_II_supernova">you need about nine solar masses</a>.  The nearest supernova candidate is <a href="http://en.wikipedia.org/wiki/Supernova#Milky_Way_candidates">IK Pegasi (HR 8210), located at a distance of 150 light-years</a> (and that's a <a href="http://en.wikipedia.org/wiki/Type_Ia_supernova">Type Ia</a>). <a href="http://en.wikipedia.org/wiki/Spica">The closest Type II candidate that I can think of is Spica</a>, which is 260 light years away. <a href="http://en.wikipedia.org/wiki/List_of_supernova_candidates">Although this list doesn't include Spica</a>, and has the closest <a href="http://en.wikipedia.org/wiki/Type_II_supernova">Type II</a> as <a href="http://en.wikipedia.org/wiki/Betelgeuse">Betelgeuse</a>, at 640 light years away.</p>

<p>In his book, <em><a href="http://rads.stackoverflow.com/amzn/click/0670019976">Death From The Skies</a></em>, <a href="http://blogs.discovermagazine.com/badastronomy/">Dr. Phil Plait</a> (a professional astronomer, writer, lecturer, etc.) covers exactly what would happen to earth if a star nearby <em>did</em> go supernova, and it isn't pretty. Basically, it would strip us of our <a href="http://en.wikipedia.org/wiki/Ozone_layer">ozone layer</a> and turn the upper layer of our atmosphere into a dirty brown smog layer, let in a lot of UV radiation that would devastate plankton and plant life, and be very bad for all life down on the surface. However, for a Type II, they need to be around 25 light years or closer to affect us.  Dr Plait's writing style is very much geared for a layman reader, and explains things in a very conversational tone, so I highly suggest that you get the book and read it. It will tell you exactly what to expect, and also tell you exactly why it's nothing to worry about.</p>

<p>All that said, there are two things in his book that you may want to consider as more likely than a supernova. A <a href="http://en.wikipedia.org/wiki/Gamma-ray_burst">GRB</a> from <a href="http://en.wikipedia.org/wiki/Eta_Carinae">Eta Carinae</a>, or an asteroid impact. The latter we may actually have the technology to eliminate as a concern though, so we're not doing too badly!</p>

CC BY-SA 4.0
2020-08-17T14:16:13.423Z
I thought you need more than 1.4 solar masses (Chandrasekhar limit) for a star to go supernova. So if I understand you correctly, a star above 1.4 solar masses but below 9 solar masses would turn into a neutron star (instead of a white dwarf) but _not_ go supernova (instead it would eject a planetary nebula)?
Giovanni
CC BY-SA 4.0
2020-08-17T16:02:54.097Z
The 1.4 mass refers to the core mass. Hence why it sort of refers to the Type I with a white dwarf as it is basically just a core. Type II still requires the overall stellar mass to be well above our solar mass: https://en.wikipedia.org/wiki/Type_II_supernova
Larian LeQuella
CC BY-SA 4.0
2020-08-17T16:51:31.417Z
So a star that has at least 9 solar masses _does_ have a core of more than 1.4 solar masses so it can go supernova?
Giovanni
CC BY-SA 4.0
2020-08-17T17:45:30.423Z
It's a little more complex than that in detail, but essentially yes. :)
Larian LeQuella
CC BY-SA 4.0
2020-08-17T17:55:09.573Z
Thank you. I always thought the 1.4 mass referred to the entire star. But Sirius A is anyway to lose enough mass during its evolution so its mass will fall even lower for becoming a stable white dwarf.
Giovanni
CC BY-SA 3.0
2013-09-26T02:19:43.550Z
2013-09-26T02:19:43.550Z
Larian LeQuella
<p>There are 51 stars within 17 light years of the Earth (<a href="http://en.wikipedia.org/wiki/List_of_nearest_stars">source</a>). If one of these stars was to become a supernova, how would they effect the Earth?</p>

<supernova>
Near-Earth supernova
Larian LeQuella
# Near-Earth supernova

(Asked by: username_0 on 2013-09-26)

There are 51 stars within 17 light years of the Earth ([source](http://en.wikipedia.org/wiki/List_of_nearest_stars)). If one of these stars was to become a supernova, how would they effect the Earth?

**Tags:** supernova

---

## 1 answers

### Answer by username_0 on 2013-09-26. Score: 20 | Accepted answer

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](http://en.wikipedia.org/wiki/Sirius#Sirius_A) (an [A sequence](http://en.wikipedia.org/wiki/Stellar_classification#Class_A) 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](http://en.wikipedia.org/wiki/A_V_star). In order to go supernova though, [you need about nine solar masses](http://en.wikipedia.org/wiki/Type_II_supernova). The nearest supernova candidate is [IK Pegasi (HR 8210), located at a distance of 150 light-years](http://en.wikipedia.org/wiki/Supernova#Milky_Way_candidates) (and that's a [Type Ia](http://en.wikipedia.org/wiki/Type_Ia_supernova)). [The closest Type II candidate that I can think of is Spica](http://en.wikipedia.org/wiki/Spica), which is 260 light years away. [Although this list doesn't include Spica](http://en.wikipedia.org/wiki/List_of_supernova_candidates), and has the closest [Type II](http://en.wikipedia.org/wiki/Type_II_supernova) as [Betelgeuse](http://en.wikipedia.org/wiki/Betelgeuse), at 640 light years away.

In his book, *[Death From The Skies](http://rads.stackoverflow.com/amzn/click/0670019976)*, [Dr. Phil Plait](http://blogs.discovermagazine.com/badastronomy/) (a professional astronomer, writer, lecturer, etc.) covers exactly what would happen to earth if a star nearby *did* go supernova, and it isn't pretty. Basically, it would strip us of our [ozone layer](http://en.wikipedia.org/wiki/Ozone_layer) and turn the upper layer of our atmosphere into a dirty brown smog layer, let in a lot of UV radiation that would devastate plankton and plant life, and be very bad for all life down on the surface. However, for a Type II, they need to be around 25 light years or closer to affect us. Dr Plait's writing style is very much geared for a layman reader, and explains things in a very conversational tone, so I highly suggest that you get the book and read it. It will tell you exactly what to expect, and also tell you exactly why it's nothing to worry about.

All that said, there are two things in his book that you may want to consider as more likely than a supernova. A [GRB](http://en.wikipedia.org/wiki/Gamma-ray_burst) from [Eta Carinae](http://en.wikipedia.org/wiki/Eta_Carinae), or an asteroid impact. The latter we may actually have the technology to eliminate as a concern though, so we're not doing too badly!

> **Comments:**
> **username_1**: I thought you need more than 1.4 solar masses (Chandrasekhar limit) for a star to go supernova. So if I understand you correctly, a star above 1.4 solar masses but below 9 solar masses would turn into a neutron star (instead of a white dwarf) but _not_ go supernova (instead it would eject a planetary nebula)?  
> **username_0**: The 1.4 mass refers to the core mass. Hence why it sort of refers to the Type I with a white dwarf as it is basically just a core. Type II still requires the overall stellar mass to be well above our solar mass: https://en.wikipedia.org/wiki/Type_II_supernova  
> **username_1**: So a star that has at least 9 solar masses _does_ have a core of more than 1.4 solar masses so it can go supernova?  
> **username_0**: It's a little more complex than that in detail, but essentially yes. :)  
> **username_1**: Thank you. I always thought the 1.4 mass referred to the entire star. But Sirius A is anyway to lose enough mass during its evolution so its mass will fall even lower for becoming a stable white dwarf.  

---

