RS OphiuchiThe narrow double star RS Ophiuchi is a recurring nova, which erupts about every 20 years. The last eruption was on February 26th, 2006. In the stellar system the white dwarf (B) even moves within the thin gas hull of the red giant RS Ophiuchi A.This is remarkable, because the white dwarf has a mass only slightly below te Chandrasekhar limit. It draws off mass from the red one, so it will excess this limit of 1.44 solar masses sometime and then will explode as a type Ia supernova. When this will happen exactly we don't know of course, probably within the next 100 000 years. So that's no reason to worry yet, the more so as it is too far away to be a hazard for our Earth. The B star sends out jets, something like this is known from no other white dwarf. Furthermore there is a gas disk around it, which will explode as a nova again soon. Constellation: Ophiuchus Distance: 5200 light-years Visual magnitude: 12.5
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Graphic: Rob Hynes, LSU |
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