14467( 4) - 29-Jan-2016 16:25:45 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14467 Version: 4 Check-in Time: 29-Jan-2016 16:25:45 STScI Edit Number: 0 Title A White Dwarf with an Actively Disintegrating Asteroid ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Siyi Xu European Southern Observatory - Germany Y CoI: Mr. Andrew Vanderburg Harvard University N CoI: Dr. Michael Jura University of California - Los Angeles N CoI: Dr. John Henry Debes Space Telescope Science Institute N CoI: Dr. Patrick Dufour Universite de Montreal N CoI: Dr. Philip Steven Muirhead Boston University N CoI: Dr. Bryce J Croll Boston University N CoI: Prof. Ben M. Zuckerman University of California - Los Angeles N ------------------------------------------------------------------------------------ Abstract We have recently discovered a white dwarf where an asteroid is actively disintegrating. Using data from K2, transits with periods less than 5 hours have been detected from at least 6 fragments. Evidence for circumstellar dust is found by comparing UKIDSS and WISE data. High-resolution optical spectroscopic data from Keck show that the host star is heavily polluted with 11 heavy elements and circumstellar gas. We propose follow-up with time-resolved ultraviolet spectroscopy with the Cosmic Origins Spectrograph to: (i) detect new photospheric elements such as carbon; (ii) monitor any changes of the circumstellar absorption lines during a transit; (iii) measure a transit light curve in the ultraviolet to compare with simultaneous ground-based photometry which we will separately acquire. ------------------------------------------------------------------------------------ Observations Description ------------------------ We aim to understand WD 1145+017 system, which has a heavily polluted atmosphere, a dust disk, circumstellar gas as well as six or more transiting planetesimals. Specifically, our goal is threefold: (i) to detect new elements that only have transitions in the ultraviolet; (ii) use TIME-TAG data to monitor the potential changes of circumstellar lines; (iii) measure a transit light curve in the ultraviolet. To cover all the lines of interest, we will employ the G130M grating with a central wavelength of 1291 Angstrom and a wavelength coverage of 1137-1274 Angstrom and 1292-1432 Angstrom. For target acquisition, we will employ both ACQ/SEARCH and ACQ/IMG. ------------------------------------------------------------------------------------ 14467( 4) - 29-Jan-2016 16:25:45 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WD-1145+017 STAR, DB RA=11H48M33.6270S +/- 0.04", J2000 V = 17.3 DEC=+01D28'59.45" +/- 0.043" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.002887634121500669 -0.007 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 14467( 4) - 29-Jan-2016 16:25:45 - [ 3] Visit: 01 Visit Requirements: SCHED 40% On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 WD-1145+017 COS/NUV ACQ/IMA PSA MIRRORB 1 20 S (20 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 WD-1145+017 COS/FUV TIME-TA PSA G130M 1291 SEGMENT=BOTH, FP-POS=ALL, 1 1000 S G FLASH=YES, BUFFER-TIME=480 see below (1920 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 WD-1145+017 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=480, SEGMENT=BOTH, 1 2940 S G FLASH=YES, FP-POS=1 see below (2870 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 WD-1145+017 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=480, SEGMENT=BOTH, 1 2945 S G FLASH=YES, FP-POS=2 see below (2870 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 WD-1145+017 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=480, SEGMENT=BOTH, 1 2945 S G FLASH=YES, FP-POS=3 see below (2870 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WD-1145+017 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=480, SEGMENT=BOTH, 1 2944 S G FLASH=YES, FP-POS=4 see below (2870 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WD-1145+017 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE WD-1145+017 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 480.0 S G WD-1145+017 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 480.0 S G WD-1145+017 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 480.0 S G WD-1145+017 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 480.0 S G WD-1145+017 3 COS/FUV TIME-TA PSA G130M 1291 none none none none 2 2870.0 S G 14467( 4) - 29-Jan-2016 16:25:45 - [ 4] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ WD-1145+017 4 COS/FUV TIME-TA PSA G130M 1291 none none none none 3 2870.0 S G WD-1145+017 5 COS/FUV TIME-TA PSA G130M 1291 none none none none 4 2870.0 S G WD-1145+017 6 COS/FUV TIME-TA PSA G130M 1291 none none none none 5 2870.0 S G 14467( 4) - 29-Jan-2016 16:25:45 - [ 5] Summary Form for Proposal 14467 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=480, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, FP-POS=ALL, SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SCHED 40% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names WD-1145+017 ------------------------------------------------------------------------------------------------------------------------------------