The dwarf planet Haumea has a fascinating history, including the formation of two large satellites by an ancient mantle-shattering collision. Haumea also has an exciting future with many observable mutual events between Haumea and the smaller inner moon Namaka predicted for the next several years. The Haumea-Namaka mutual events will provide a wealth of information that is otherwise unattainable: the size, shape, and spin pole of Haumea; the size, albedo, and density of Namaka; and precise orbital constraints. The orbital orientation is not as favorable for the outer, larger satellite Hi'iaka, but the last mutual event between Hi'iaka and Namaka occurs on July 2, 2009 and will not occur again for a century. As a follow-up to our observations of the last satellite-satellite event (Program 11971), we propose a short (7-orbit) STIS resolved photometry program to observe the last of these events, which will occur with an estimated ~93% probability. Even catching a partial event can measure the density of Hi'iaka to within ~15% and provide unique insight in the formation and evolution of this exciting system.

Observations of a satellite-satellite mutual event of the dwarf planet Haumea. The goal is to obtain precise photometry of a (resolved) faint satellite to a moving object (located near 13:36:08, +19:27:00). The observations are designed to maximize overall signal-to-noise (by maximizing total exposure time), while taking multiple observations to produce a high-cadence light curve. All 7 orbits must be taken as close as possible to (02-JUL-2009 04:45:00). Seven consecutive orbits must be taken, with the first exposure occurring between 01-JUL-2009:21:30:00 and 01-JUL-2009:23:30:00. These observations could be taken with other instruments or in "engineering time." Please contact the PI (darin@caltech.edu) at any time for questions. 0 false 0.0 0.0 false false false false false SUPPORTED SOLAR SYSTEM At the time of the observations, the approximate RA and Dec are 13:36:08, +19:27:00 ASTEROID (136108) Dwarf Planet Haumea and its Two Satellites TYPE=ASTEROID,A=43.1359862,E=0.1949506,I=28.2244,O=122.1032,W=239.18665,M=202.66919,EQUINOX=J2000,EPOCH=30-NOV-2008:00:00:00 EARTH POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 6 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 7 false POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 8 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 8 false POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 9 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 9 false POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 10 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 10 false POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 12 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 11 false POS-TARG MOSAIC DITHER 0.4056 The purpose of the dither pattern is to reduce the effects of hot pixels to improve photometric accuracy. Ideal dither spacing is an integer number of pixels, since a stable PSF is more important than a sub-sampled PSF: 0.4056" = 8 pixels. Dither spacing is large enough to significantly displace hot pixels with respect to the PSF size, but small enough to keep the observations near the middle of the detector and to minimize slew time. By the suggestion of Charles Profitt, we are going to be dither perpendicular to the slit to minimize variable CTE effects. STIS-ALONG-SLIT false false 13 0.0 POS-TARG STIS-PERP-TO-SLIT 90.0 12 false Using ephemeris for target 12004-01-HAUMEA ephemeris data for target 12004-01-HAUMEA does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 08.220 to 10.182. ephemeris interval: 09.151 to 11.152 The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. Observation of the Haumea satellite-satellite mutual event through resolved photometry. The first observation of seven consecutive orbits should occur between 01-JUL-2009:21:30:00 and 01-JUL-2009:23:30:00, in order to observe the event. The observations are designed to maximize overall signal-to-noise (by minimizing read and overhead time), while achieving high temporal cadence and avoiding saturation of the primary (~58 seconds).Observations should consist of the maximum number of 40 second observations during visible time. The satellites are directly South of Haumea, so please choose ORIENT near 135 degrees, instead of near 90 degrees, in order to keep the diffraction spikes off of the satellites and to improve the faint satellite search. This orientation is a secondary requirement, and it can be relaxed or dropped if necessary. (Tic-Visit :proposal-id 12004 :visit-id "01" :proposal-version -1 :trans-version "20080609" :date "15-Jun-2009 15:01:25.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 7 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 744704 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12004 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 12004 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 1374 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 2 :pcs-time 195 :si-vis-utilization 1814 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 3 :pcs-time 195 :si-vis-utilization 2044 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 4 :pcs-time 195 :si-vis-utilization 2277 :al-overhead-at-end 0 :internal-dur-at-end 450 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 5 :pcs-time 195 :si-vis-utilization 2754 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 6 :pcs-time 195 :si-vis-utilization 2734 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12004 :visit-id "01" :orbit-number 7 :pcs-time 195 :si-vis-utilization 2967 :al-overhead-at-end 0 :internal-dur-at-end 450 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) false 7 0