How long does it take a white dwarf star turn supernova?

Question

Lets look at sirus b a white dwarf star 8 light years away.If astromoners found out tomorrow that Sirus b was turning super nova.How long would that give us before the gamma rays from the super nova wipes us out.Will the people on the oppisite side of the earth from the gamma radiation receive the same amount of radiation and will going underground help save us.

Answer 1

White Dwarfs do not turn into a supernova, they do not have sufficient mass. They turn into Black Dwarfs,

Answer 2

the ONLY way a star going super nova would hurt us, is if one of it's poles were pointed DIRECTLY at us (not just really close)

yes the other side of the earth will get just as much radiation and destruction

and no going underground won't save you. it may help prolong your life expentancy, but this is a MASSIVE dose of radiation, even if we tunneled down deep in the earth we'd see the radiation reaches there as well.

Answer 3

White dwarfs are already dead stars.  They do not supernova.  Supernovas occur in high mass stars.  Stars that produce white dwarfs, like our sun in about 5 billion years, are smaller.

Answer 4

A white dwarf is a 2 solar mass star about 100 km in diameter with insufficient mass to even collapse to a neutron star.

  A white dwarf requires the addition of mass to collapse to a neutron star which is about 16 km in diameter.

  Only massive stars [10 solar masses or more]can explode as super novas.

Answer 5

So many ignorant answers! Obviously some of the people don't know what a Type 1a Supernova is. Hint - it has something to do with white dwarfs.

The fact that Sirius is over 8 light years away means that 8 years is the minimum time we would have for anything to reach us. I think it's an understatement to say that it would be very bad for life on Earth. I don't think it would matter which part of the Earth you were on, space would be filled with high energy particles so there would be no escape.

I think it's unlikely to ever happen though.

Answer 6

Normaly white dwarfs do not super nova but in the case of sirius b it is sucking gas of its counterpart once the white dwarf reaches 40% of the mass of our son it will supernova a type one 1 supernova there always the same throughout the univerese.

Answer 7

A white dwarf will not go supernova under normal circumstances.  The dwarf state is what happens to a small to medium sized star after first swelling into a red giant, then collapsing under it's own mass.  These stars don't have sufficient mass to go supernova.  On rare occasions, white dwarfs can generate an explosion (called a type Ia supernova), but such events are infrequent.  They only occur in the milky way once every 1000 years or so, and considering the size of our galaxy (100,000 light years across), the odds of one happening near us any time soon aren't very high.  Those who are saying that white dwarfs never go supernova are incorrect, though.

A large, giant, or hyper-giant star does contain enough mass to generate a supernova explosion, however, such an event would only be harmful to the earth if one of the star's poles was facing towards us.  Even a relatively close-by star wouldn't harm us, so long as its poles weren't directed at us.

Sirius B won't go supernova.  It burnt itself out long ago, and is currently in a white dwarf state, destined to cool off over many billions of years, first becoming a brown dwarf, and then a black dwarf.

A near-earth supernova (less than 100 light years away) could deplete the ozone layer, exposing the surface to solar and cosmic radiation.  Both sides of the earth would be equally affected, since it rotates (the gamma rays wouldn't pass by in a matter of minutes, the earth would be exposed to them for years), and the reactions within the ozone layer would affect the whole planet even if we were stationary.  Some have theorized that a nearby supernova was the cause of at least one of the mass extinction events in earth's history.  However, such an event is unlikely to occur anytime soon, so I wouldn't worry about it.

Answer 8

white dwarfs are result of stars that arent big enough of to explode in supernova. for example our sun, its not big enough to actually explode it will just expand then shrink down to white dwarf then a black dwarf.

Answer 9

white dwarfs dont turn into supernova and sirius b is a white dwarf