14117( 2) - 20-Jul-2015 13:01:19 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14117 Version: 2 Check-in Time: 20-Jul-2015 13:01:19 STScI Edit Number: 0 Title A Young White Dwarf with an Infrared Excess: Dust Disk or Substellar Companion? ------------------------------------------------------------------------------------ Type Cycle GO 23 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Siyi Xu European Southern Observatory - Germany Y CoI: Dr. Michael Jura University of California - Los Angeles N CoI: Prof. Ben M. Zuckerman University of California - Los Angeles N ------------------------------------------------------------------------------------ Abstract We recently discovered the youngest white dwarf with 2-8 micron emission. Its SED can be fit by either a dust disk or a substellar companion. Two unique properties of this object favor the substellar companion hypothesis: (i) the color of the infrared excess; (ii) the non-detection of heavy elements with Keck/HIRES observations. We propose to use COS to look for heavy elements; which would be about two orders of magnitude more sensitive than the HIRES studies. If heavy elements are detected, the excess emission is likely to come from dust and this would be the hottest white dwarf with a ~1200 K dust disk; otherwise, the excess is likely to come from a substellar companion, possibly a rejuvenated planet, which would rank among the closest and lowest mass companions known to orbit a white dwarf. ------------------------------------------------------------------------------------ Observations Description ------------------------ Our goal is to look for heavy elements in the atmosphere of PG 0010+280 to understand the origin of its infrared excess. The strongest photospheric line comes from silicon, including Si II 1265 A, Si III 1299 A and Si IV 1392 A. We will employ the G130M grating with a central wavelength of 1291 A and a wavelength coverage of 1137-1274 A and 1292-1432 A.Extrapolating from the GALEX flux, we found that an average S/N of 45 can be reached with an exposure time of 2200 sec (1 orbit) according to the ETC. To minimize the fixed-pattern noise, all four FP-POS steps are used. ------------------------------------------------------------------------------------ 14117( 2) - 20-Jul-2015 13:01:19 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PG0010+280 STAR, DA RA=00H13M21.0390S +/- 0.133", J2000 V = 15.7 DEC=+28D20'19.89" +/- 0.133" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 1.590627799879649E-4 -0.013 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 14117( 2) - 20-Jul-2015 13:01:19 - [ 3] Visit: 01 Visit Requirements: 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 PG0010+280 COS/FUV ACQ/SEA PSA G130M 1291 CENTER=FLUX-WT-FLR, 1 1 S (1 S) RCH SCAN-SIZE=3, SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 2 PG0010+280 COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH 1 1 S (1 S) KXD ------------------------------------------------------------------------------------------------------------------------------------ 3 PG0010+280 COS/FUV ACQ/PEA PSA G130M 1291 CENTER=FLUX-WT-FLR, NUM-POS=5, 1 1 S (1 S) KD SEGMENT=BOTH, STEP-SIZE=0.9 ------------------------------------------------------------------------------------------------------------------------------------ 4 PG0010+280 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=330, FLASH=YES, 1 439 S G FP-POS=ALL, SEGMENT=BOTH see below (1761 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 | ------------------------------------------------------------------------------------------------------------------------------------ PG0010+280 1 COS/FUV ACQ/SEA PSA G130M 1291 none none none none 1 N/A RCH PG0010+280 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KXD PG0010+280 3 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A KD PG0010+280 4 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 441.0 S G PG0010+280 4 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 440.0 S G PG0010+280 4 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 440.0 S G PG0010+280 4 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 440.0 S G 14117( 2) - 20-Jul-2015 13:01:19 - [ 4] Summary Form for Proposal 14117 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=330, CENTER=FLUX-WT-FLR, FLASH=YES, FP-POS=ALL, NUM-POS=5, SCAN-SIZE=3, SEGMENT=BOTH, STEP-SIZE=0.9 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M ------------------------------------------------------------------------------------------------------------------------------------ Target Names PG0010+280 ------------------------------------------------------------------------------------------------------------------------------------