Jupiter Trojan Lightcurve Project
Joshua Emery of NASA Ames Research Center needs lightcurves on Jupiter Trojans:
I'm an astronomer at NASA Ames Research Center, studying the Jupiter Trojan asteroids.
Along with several colleagues, I have a program to observe several Trojans with the
Spitzer Space Telescope. None of the objects on our target list has very good light
curve data, and many of them have no info whatsoever.
Rotational data on these objects would really make our analysis of the Spitzer data more
robust, especially if the light curve observations are close in time to the Spitzer
observations, and I was wondering if you could help us let people know that we would
appreciate such observations.
Unfortunately, Spitzer only announces its schedule a few weeks in advance, so right now we
don't know exactly when our targets will be observed. But since most of the targets
don't have any light curve info, anytime anyone can observe would help. I could send
a list of dates when each object is observable with Spitzer, if it would be helpful.
What I want kind of depends on what I can get. The following list is arranged from "really need" to "would be terrific if possible."
Amplitude - if I get nothing else, this allows me to put a realistic estimate on my albedo estimate from thermal observations (since I won't have simultaneous visible, unless . . .
Period - necessary to reasonably constrain thermal inertia of the surface.
Calibrated brightness - H magnitudes of some of these guys are not very good, probably because they haven't had lightcurve and phase effects removed.
- Close-in-time light curve - A flux calibrated light curve within a few rotations of the Spitzer observations would be heaven. Knowing the rotational phase of of the Spitzer observations would let me get a very good size and albedo (and would tighten estimates of thermal inertia, though a pole position is needed to do this well.
0.01 to 0.03 mag precision would be just fine, and I would very much enjoy having the
data sent to me.
I very much encourage anyone who collects data to publish it as soon as they can.
Please don't have them wait for me. That gives everyone the chance to do as much as
they can with the data.
Below is a list of when each object is observable with Spitzer.
Object Window 1 Window 2
---------------- -------------------- --------------------
588 Achilles 01 Oct - 11 Nov 2006 05 Jun - 13 Jul 2007
617 Patroclus 22 Jan - 03 Mar 2007 20 Jun - 01 Aug 2007
(Patroclus is a binary, whose rotation is well studied now)
659 Nestor 28 May - 08 Jul 2007
1437 Diomedes 01 Nov - 10 Dec 2006 30 May - 06 Jul 2007
1867 Deiphobus 16 Jan - 02 Mar 2007 11 Jun - 28 Jul 2007
2797 Teucer 30 May - 13 Jul 2007
3548 Eurybates 14 Oct - 22 Nov 2006 10 May - 18 Jun 2007
4035 (1986 WD) 30 Sep - 11 Nov 2006 08 Jun - 20 Jul 2007
4060 Deipylos 02 Oct - 12 Nov 2006 02 Jun - 13 Jul 2007
11395 (1998 XN77) 14 Jun - 29 Jul 2007
627 Hektor already observed by Spitzer, but LC wouldn't hurt
911 Agamemnon already observed by Spitzer, but LC wouldn't hurt
1172 Aneas already observed by Spitzer, but LC wouldn't hurt
4709 Ennomos already observed by Spitzer, but LC wouldn't hurt
Extinct JFCs:
1922 Zulu 06 Apr - 03 Jun 2007
7304 Namiki 26 Jan - 02 May 2007
19752 (2000 CH67) 08 Dec - 20 Jan 06/07 08 May - 20 Jun 2007
30512 (2001 HO8) 28 Feb - 13 Apr 2007
(2002 AT4) 27 Feb - 26 Apr 2007
Announced Spitzer Observing Times
If at all possible, lightcurves at the same time or within hours will be of even greater help. Dates and Times are UT. Ephemerides are geocentric for 00:00 UT.
SCHEDULED TIME AOT TYPE TARGET NAME AOR LABEL ----------------------- --------- ----------- ---------------------- jun 11 2007 19:14:31.000 IrsStare 1867 Deiphobus IRSS-1867deiphobus jun 12 2007 22:11:32.200 IrsStare Teucer IRSS-2797teucer jun 12 2007 23:04:10.200 IrsStare Nestor IRSS-659nestor jun 13 2007 07:11:53.400 IrsStare Deipylos IRSS-4060deipylos jun 13 2007 08:12:12.400 IrsStare 1986 WD IRSS-4035_1986wd jun 13 2007 09:23:25.900 IrsStare Achilles IRSS-588achilles Mag: Estimated V magnitude PA: Phase Angle E: Solar elongation Ephemeris for: 1867 Deiphobus DATE UT RA(2000) DC(2000) Mag PA E ------------------------------------------------------------ 06/05/2007 00:00 10 59.54 -24 48.0 16.28 11.2 101 06/10/2007 00:00 11 01.26 -24 32.5 16.31 11.3 97 06/15/2007 00:00 11 03.27 -24 19.1 16.34 11.4 93 06/20/2007 00:00 11 05.54 -24 07.9 16.37 11.4 90 06/25/2007 00:00 11 08.06 -23 59.0 16.40 11.4 86 Ephemeris for: 2797 Teucer DATE UT RA(2000) DC(2000) Mag PA E ----------------------------------------------------------- 06/05/2007 00:00 22 05.50 -34 49.8 16.29 9.8 111 06/10/2007 00:00 22 06.10 -35 10.8 16.25 9.5 116 06/15/2007 00:00 22 06.37 -35 33.2 16.20 9.1 120 06/20/2007 00:00 22 06.29 -35 56.9 16.16 8.7 124 06/25/2007 00:00 22 05.86 -36 21.5 16.11 8.2 129 Ephemeris for: 659 Nestor DATE UT RA(2000) DC(2000) Mag PA E ----------------------------------------------------------- 06/05/2007 00:00 21 25.95 -18 52.2 16.08 11.4 116 06/10/2007 00:00 21 26.09 -18 53.2 16.03 10.9 121 06/15/2007 00:00 21 25.87 -18 55.7 15.97 10.3 126 06/20/2007 00:00 21 25.30 -18 59.6 15.91 9.6 130 06/25/2007 00:00 21 24.38 -19 04.9 15.84 8.9 135 Ephemeris for: 4060 Deipylos DATE UT RA(2000) DC(2000) Mag PA E ----------------------------------------------------------- 06/05/2007 00:00 21 27.44 - 4 22.1 17.14 9.1 111 06/10/2007 00:00 21 27.29 - 4 19.2 17.10 8.8 115 06/15/2007 00:00 21 26.89 - 4 18.0 17.05 8.4 120 06/20/2007 00:00 21 26.24 - 4 18.3 17.01 8.0 125 06/25/2007 00:00 21 25.34 - 4 20.3 16.96 7.5 130 Ephemeris for: 4035 1986 WD DATE UT RA(2000) DC(2000) Mag PA E ----------------------------------------------------------- 06/05/2007 00:00 21 44.34 + 0 07.0 17.13 10.5 105 06/10/2007 00:00 21 44.54 + 0 20.9 17.08 10.2 110 06/15/2007 00:00 21 44.47 + 0 33.3 17.04 9.9 114 06/20/2007 00:00 21 44.11 + 0 44.0 16.99 9.5 119 06/25/2007 00:00 21 43.48 + 0 53.0 16.94 9.1 123 Ephemeris for: 588 Achilles DATE UT RA(2000) DC(2000) Mag PA E ------------------------------------------------------------ 06/05/2007 00:00 21 44.79 -14 05.7 16.67 9.7 110 06/10/2007 00:00 21 44.79 -14 01.8 16.62 9.3 115 06/15/2007 00:00 21 44.51 -13 59.3 16.57 9.0 120 06/20/2007 00:00 21 43.94 -13 58.0 16.52 8.5 125 06/25/2007 00:00 21 43.09 -13 58.1 16.47 8.0 130
Brian D. Warner
Palmer Divide Observatory (716)
17995 Bakers Farm Rd.
Colorado Springs, CO 80908