Expert: Jayendra Upadhye - 6/25/2008

Question
If a type 1a supernova, such as HR 8210 "IK Pegasi" for example exploded, would it be a threat to us on earth at the current distance 150 lightyears away?

Answer
Hi,
[refer:-http://en.wikipedia.org/wiki/IK_Pegasi].

The 1k pegasi system is currently 150 light years away from us, and receding at about 20.4 km/sec, as found by various means.
[refer para "observation"].

For a supernova to effectively deplete the earth's ozone layer completely, and thus cause grave damage to life, it should be at least 26 light years away.

At the current rate of recession (not hubble recession, but due to its proper natural velocity thru real space), this is equivalent to moving a distance of one light year every 14,700 years. After 5 million years, for example, this star will be separated from the Sun by more than 500 light years. This is outside the radius where a Type Ia supernova is thought to be hazardous.
[refer para Future evolution].

Conclusion:-
No. It will take about 5 million years for component A to reach the red gian phase, by which time the system will be about 500 lightyears or more from the sun, which is a safe distance from type 1a supernovas.

regards
Jayen