Re: appendix: Astronomy Campfire
If ye would like to moderate the Astronomy Campfire, please drop becket@jollyroger.com a
line. Astronomy & Re: appendix
Posted by Astroman on October 08, 192002 at 13:44:00:
In Reply to: appendix posted by pete s on September 29, 192002 at 10:17:30:
I checked out astronomy.net just for the fun of it. (I've been on an observing run and out of the office for some time, so it took a while to respond.) It seems you're not alone in your beliefs of making physics out of thin air. ;-) I also looked up the bursts you mention and come up with the following ysis. Neither burst was particularly energetic, (emitting mostly in the hard to soft x-ray region, rather than gamma rays), accurately located, noteworthy or well studied. These 2 bursts came at a time when the data were downloaded from the satellite twice per day, so considerable fading had occurred before anyone on Earth new they happened. No optical transient was suspected, much less observed and this is where most of the information is gleaned from a burst. Now, BATSE trigger 5079 gave a location well over 8 full degrees away from 40 Eridanis. Not a snowballs chance in Hades it's related to any emissions from that star. It may as well have been in a different constellation. While the catalog itself says the locations are not that good, 8 degrees is excessive, especially for BATSE. While trigger 3914 is closer to a star in Pyxis, there's no evidence of a relationship between the burst and the star. I'm also not familiar with the catalog you cite-LP532-81. I did find the star to be HD200000. Strange, it should be such an even number... "Flukey to see 3 out of 3..." I count a "sample" of 2. Astronomically, even for GRB's a sample of 2 is meaningless.
>The delay in years from the supernova to the burst is found by Delay(years)= d.(1-cosa) where d is the distance to the star in lightyears and a is the angle between star and supernova.
Supernova debris travel at supersonic speeds, not relativistic speeds. Debris from an expanding SN cloud would take eons to travel to the nearest star. Add that to the distance to us and you get into some really big numbers.
>There was a prediction for Van Maanens star in Mar 2001 but NASA decided to reposition the Compton after I posted this info 3 years ago and as I suspected it never saw anything from its new location. A pity because only BATSE saw these two events.
A prediction of a GRB? SN? Wow, I wasn't aware we'd come to predicting them. "Reposition Compton" is an interesting choice of words, since they deorbited it in June 2000. Dr. Fishman still can't talk about it without raising his blood pressure. It was a political decision, rather than a scientific/tactical decision. The shuttle would have been very capable of repaiering CGRO, but the been counters nixed it. Sad.