Bob Moler's Ephemeris Blog

This is Bob Moler with Ephemeris for Veterans Day, Tuesday, November 11th. Today the Sun will be up for 9 hours and 43 minutes, setting at 5:18, and it will rise tomorrow at 7:36. The Moon, 1 day before last quarter, will rise at 11:37 this evening.

I’ve always wondered what the difference is between a nova like T Coronae Borealis, sometimes called the Blaze Star, and a Type 1a supernova. Both involve a white dwarf star and a larger star and having the mass of the larger star being drawn off onto the surface of the white dwarf until an explosion happens. If the detonation, which is a thermonuclear detonation of the hydrogen drawn off the larger star, is on the surface only, involving the outer layers of the white dwarf, the star becomes thousands of times brighter for a short period of time. The star survives. In the Type 1a supernova, the accretion of the hydrogen onto the white dwarf causes a more massive explosion involving the core of the white dwarf because its mass approaches or will surpass 1.4 times the Sun’s mass. At that point the star explodes.

The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.

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