Comet Orbits

I know many of you refer frequently to the comet track images we've had on the Sungrazer site for a long time. Those images (which are in the process of being updated) provide a great reference for where to look in the data. But it also occurred to me some time ago that orbit simulations might be helpful too. So my coworker Brendan has compiled some really excellent animations that show the orbits of the various comets in the LASCO and (for Kreutz) the STEREO-A/SECCHI fields of view. 

You can see the SOHO orbits here, with an animation for the Kreutz, Meyer, Marsden and Kracht groups. As most of you know, SOHO orbits the Sun once per year, which means that we see the same part of the sky on every day of the year. This means that we only need to produce a simulation of one year of data, and it will work for every other year. So those animations use 2002 images but the month/day is entirely applicable to any other year in the SOHO mission.

STEREO/SECCHI-A does NOT follow the same 1-year orbit that SOHO does, which means that the position of the Kreutz comets will vary every year.  So Brendan has also produced this really nice 8-yr simulation of the Kreutz orbit in COR2 and HI1 from 2015 through 2023. I believe the comet orbit is based upon Comet Lovejoy's as a proxy for the nominal Kreutz orbit. Of course we know that many of the Kreutz we observe are outliers of this orbit, but the simulation gives a great indication of roughly when/where they will be in the data. It's a really cool animation so I'll post it here so you don't have to jump to the other page straight away.

Eight years (2015 - 2023) of the Kreutz orbit in STEREO-A/SECCHI COR-2 and HI-1.
Direct download 3.2Mb mp4. [Credit: Brendan Gallagher (NRL).]