Target QUAOAR: There is no need or capability to test the scheduling of observations of moving targets in Phase I. This warning will go away the next time the proposal is loaded.0Your proposal could not be saved.
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Assigned ID: 4493
----- Attempting Submission 1 (Wed May 24 18:40:14 GMT 2023) -----Test the scheduling is not possible in phase I because this is a moving target.0----- Attempting Submission 1 (Wed May 31 18:56:21 GMT 2023) -----Beating Weywot in the game of hide-and-seekWeywot is the satellite of the trans-Neptunian dwarf planet candidate Quaoar. Obtaining its physical properties, such as size and density, is pivotal in order to understand its formation scenario and to better understand the formation of binary systems in the trans-Neptunian region. Weywot was thought to be a captured satellite due to its estimated size through thermal modeling and its eccentric orbit (which should circularize in a few million years if the satellite formed via collision). However, recent fortuitous detections through stellar occultation indicate that the size could be double. This opens the debate about Weywot's formation. A stellar occultation is predicted to happen on June 22nd that would cross the continental US, providing the opportunity to prepare a good observational campaign to distribute telescopes to maximize the coverage of Weywot's limb (and surroundings). However, our resources are limited and the uncertainty of the current prediction is of around 1000 km north and south the current path. We are therefore asking for a single HST orbit to locate Weywot with respect to Quaoar so that we can reduce the uncertainty to 300 km, thus being able to obtain a highly sampled stellar occultation and decipher the mystery of Weywot's formation.A single orbit is required to image the Quaoar/Weywot TNO binary system with the WFC3/UVIS instrument and the F606W filter.
The WFC3-UVIS-BOX-DITHER pattern will be used, which is composed of 4 exposures. Each exposure will be 432 seconds long in order to optimize the efficiency of the orbit (resulting in only 3 seconds of unused time). This individual exposure time is longer than the 348-second limit under which a serial buffer dump is required and APT does not provide a warning message about adding a post-flash.
The "UVIS2" aperture was specified to ensure optimal placement within the UVIS2 detector, which has better characteristics than UVIS1.
A BEFORE special requirement is specified to ensure the observations occur before June 19th. There is an occultation by Weywot predicted on June 22nd and obtaining the data by June 19th will allow enough time to process the data. extract astrometry, and update the prediction. This timing requirement was included in the DDT proposal.PI Dr. Fernandez-Valenzuela has extensive experience using photometric techniques of faint and moving objects such as TNOs (PI of program 16306 to observe TNOs candidate to belong to Haumea's family, the only known TNO to have a dynamical family). She is also an expert in the analysis of stellar occultations and the study physical properties of TNOs.
Co-I Dr. Holler has previous experience using HST to observe TNOs and their satellites (PI of program 15171 to observe the dwarf planet Eris and its satellite, Dysnomia, with WFC3/UVIS; Co-I on snapshot program 15821 to evaluate Centaurs for binarity). He also has prior experience using PSF fitting to analyze WFC3 and ACS images.
Co-I Dr. Rommel is postdoctoral research working on the analysis of stellar occultations of TNOs. She has plenty of expertise with astrometric and photometric techniques. She is also currenlty working on rotational light curves.
Co-I Dr. Ortiz has extensive expertise in the application of astrometric techniquest to the prediction of stellar occulations. He has also plenty of expertise in the photometric analysis of the data and understanding the physical properties of TNOs and centaurs through stellar occultations.
Co-I Mr. Morales is an engineer with experience in the application of astrometric techniques to the prediction of stellar occulations. He is also an experienced observer.
Co-I Dr. Vachier Vachier is a world leader in the production of ephemeris for binary asteroids by offering this unique service in the world. It contributes to the numerical application of models by comparing them to observations already acquired by different satellite systems. His work relies on statistical methods to obtain orbital parameters and explore the internal structure of asteroids.
The entire team was part of the lead group in charge of the analysis of the stellar occultations produced by Haumea's largets satellite, Hi'iaka, in April 2021.Solar System Astronomy0falseSUPPORTEDSOLAR SYSTEMNOASTEROIDTrans-Neptunian object (TNO)TYPE=ASTEROID,A=43.35614180031197,E=0.0399368787562926,I=7.991290702148744
,O=189.0991840859715,W=158.6090073041173,M=293.8088571674838,EQUINOX=J2000,EPOCH=25-MAY-2023:00:00:00,EpochTimeScale=TDBEARTHWFC3/UVISImagingNoNoF606WPOS-TARGDITHER0.173LINE0.112falsefalse81.785423.884WFC3-UVIS-DITHER-BOX1falseUsing ephemeris for target 17315-01-QUAOARephemeris data for target 17315-01-QUAOAR does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.213 to 24.182. ephemeris interval: 23.120 to 25.121The scheduling data was generated by CASM 31.0.CASM was run in Phase II mode.1686591930000241.225003231754(Tic-Visit
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:date "31-May-2023 14:47:44.0"
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