[AZ-Observing] How many comets?
- From: Brian Skiff <Brian.Skiff@xxxxxxxxxx>
- To: amastro@xxxxxxxxxxxxxxx, az-observing@xxxxxxxxxxxxx
- Date: Mon, 19 Jan 2004 21:50:25 -0700 (MST)
I was asked a few times in the past week, following the announcement of P/2004 A1, how many comets I have. My answer is either "I don't know" or "some". Here's why. The list below shows comets that have my name attached, with as-yet-unnamed 2004 A1 shown for completeness, along with a gloss on the discovery circumstances. The IAU Circulars are the journal-of-record for comets, and the discovery announcements are available on-line at the URLs shown for each object. 140P/1983 C1 (Bowell-Skiff) found by Ted Bowell on Pluto Camera plates taken by me; Saturn-family comet http://cfa-www.harvard.edu/iauc/03700/03773.html D/1977 C1 (Skiff-Kosai) found by me on a Palomar Schmidt plate taken by Charlie Kowal, identified as asteroid previously reported by Hiroki Kosai (Kiso Schmidt); now considered lost Jupiter-family comet http://cfa-www.harvard.edu/iauc/04200/04250.html 114P/1986 Y1 (Wiseman-Skiff) found by Jennifer Wiseman on Pluto Camera plates taken by me; Jupiter-family comet http://cfa-www.harvard.edu/iauc/04200/04299.html C/1999 J2 (Skiff) found on LONEOS images; large perihelion distance with hyperbolic orbit http://cfa-www.harvard.edu/iauc/07100/07165.html C/1999 U4 (Catalina-Skiff) reported as a comet, but found the day prior by Tim Spahr at Catalina and reported only as having unusual motion by him; hyperbolic orbit http://cfa-www.harvard.edu/iauc/07200/07298.htm P/2000 S1 (Skiff) found on LONEOS images; Saturn-family comet http://cfa-www.harvard.edu/iauc/07400/07496.html C/2000 Y2 (Skiff) found on LONEOS images http://cfa-www.harvard.edu/iauc/07500/07549.html C/2001 K3 (Skiff) found on LONEOS images http://cfa-www.harvard.edu/iauc/07600/07631.html P/2001 R6 (LINEAR-Skiff) reported by me as a comet, but prediscovery LINEAR observations on two nights as an asteroid that had already been linked by the MPC; Jupiter-family comet http://cfa-www.harvard.edu/iauc/07700/07723.html C/2001 S1 (Skiff) found on LONEOS images http://cfa-www.harvard.edu/iauc/07700/07725.html P/2002 S1 (Skiff) found on LONEOS images; Jupiter-family comet http://cfa-www.harvard.edu/iauc/07900/07972.html P/2004 A1 ( ? ) found on LONEOS images as stellar but with unusual motion; identified as comet in follow-up images taken immediately afterwards with Lowell Perkins 1.8-m telescope. Centaur-like orbit. Notes: Jupiter-family comet captured objects in roughly 3:2 resonance with Jupiter, orbital periods of 7 to 9 years. many of these are perturbed inward from the Kuiper belt. Saturn-family comet captured objects in roughly 2:1 resonance with Saturn, orbital periods of about 15 years. hyperbolic orbit comet that's being thrown out of the solar system, mainly from perturbation by Jupiter. So the number of comets found by me with no one else involved is six, and maybe seven once the name for 2004 A1 is announced. The first of these didn't come until 1999, and 12 years separated it from Wiseman-Skiff. (We didn't do much survey-type asteroid observing between about 1990 and 1998, so sure enough we didn't find any comets during that interval.) Then there are the hyphenated ones where I'm given top billing or where I'm the junior partner, and ones where the names arguably should be reversed from what the official name is. I don't know how to count those, so I'll stick with the six for the moment. There are in addition several 'LONEOS' comets (some of them hyphenated as well), which were identified as comets after being reported by me as asteroidal but with unusual motion. These are similar to the case of Catalina-Skiff or LINEAR-Skiff, and are now fairly common with the many faint comets found by the big surveys (LINEAR, NEAT, LONEOS). Some (but not all) of these hyphenated comets with the survey name given rather than the observer can be regarded as failure to do our job as thoroughly as we might have. My opinion is that those comets should be named for the person who identified them as comets (and too bad for us), but that's not the way it works under the current rules. The comet-naming scheme is utterly byzantine, and seems to depend largely and mysteriously on Brian Marsden, who interprets the rules on a whim and would like to omit the names altogether. The rules have also changed over the years. After a few of these ambiguous cases, I've gotten so I don't care any more. The main thing is that the comet is picked up and made available for study. \Brian -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.
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