From: "milton_aupperle" <milton@outcastsoft.com>

Date: November 12, 2010 10:43:00 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Asteroid Devosa Light Curve

Hi folks;

I decided to record a 5 hour Light curve for Asteroid Devosa on Wednesday (Nov 10). It's approximately Mag 11.2, has a change of 0.45 to 0.86 mags and rotates once ever 4.56 hours, so it's something one can do in a single longish night (running from 9 pm to 2 am in my case).

I had a marvelous cool (-7°C ambient) night of very stable skies over a 5 hour period, with measured FWHM in the 3 to 4 arc second range (about 2x to 3x as good as normal). Tracking was superb and and the mount only needed small (<1 arc seconds) corrections at up to 15 seconds periods. That was a mixed blessing because it wound up over saturating my stars compared to other nights. That added a lot more variability and scatter to the resulting curve, as you can see below:

http://groups.yahoo.com/group/Astro_IIDC/files/Other/Devosa_20101110_MJA_LightCurve.png 

I could not make any sense of the Light curve, as I found 3 decreasing humps in a 5 hour period. The peaks occurred at about 04:53 UTC, 06:42 UTC and 08:06 UTC on 2100 11 11. An elongated shaped asteroid likely has 2 minima and maxima (depending on rotational axis), so three humps does not make much sense and I suspected the data was bogus.

Then I found these links:

http://adsabs.harvard.edu/abs/1979A&AS...35..337S

http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?2001MPBu...28...32L&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf

which indicates it's an unusual asteroid with 3 decreasing minima and maxima (humps) in each period.

Very weird, eh?

Milton Aupperle