17720( 4) - 24-Oct-2024 19:39:45 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17720 Version: 4 Check-in Time: 24-Oct-2024 19:39:45 STScI Edit Number: 2 Title Confirming the first strongly asynchronous polar ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Ilaria Caiazzo Institute of Science and Technology Y Austria CoI: Dr. Tim Cunningham Harvard University N CoI: Prof. Boris T. Gaensicke University of Warwick N CoI: Prof. Paula Szkody University of Washington N CoI: Mr. Antonio C. Rodriguez California Institute of Technology N CoI: Dr. Thomas A Prince California Institute of Technology N CoI: Mr. Andrei Alexandru Cristea Institute of Science and Technology N Austria CoI: Dr. Kevin Burdge Massachusetts Institute of Technology N ------------------------------------------------------------------------------------ Abstract We have discovered a new exotic binary system containing an accreting highly magnetized white dwarf. The peculiar variability in the hydrogen emission lines and the high magnetic field of the white dwarf hint to a very exciting explanation for the current observations: we might have caught the system in a rare evolutionary stage, in which the highly magnetized white dwarf has only recently started accreting from the companion and therefore its rotation period is not yet synchronized with the orbital period of the binary. We here propose a joint HST-XMM program to confirm the nature of this system as a strongly asynchronous polar, to constrain the magnetic field strength and temperature of the white dwarf, and to measure the accretion rate of the system. If confirmed, this system promises to become a keystone for our understanding of the evolution of cataclysmic variables and of binary evolution in general. ------------------------------------------------------------------------------------ Observations Description ------------------------ The purpose of this program is to study the SED and lightcurve of the white dwarf ZTF J2008+4449 in the UV. ZTF J12008+449 is a new exotic binary system containing an accreting highly magnetized white dwarf, which could be the first highly asynchronous polar observed. If confirmed, this system promises to become a keystone for our understanding of the evolution of cataclysmic variables. The proposed HST observations will allow us to constrain the magnetic field strength and temperature of the white dwarf, and possibly detect cyclotron emission humps. We ask for 5 orbits of COS spectroscopy and 4 orbits of STIS spectroscopy in the time-tag mode, so that we will obtain high signal-to-noise phase resolved spectra and UV lightcurves. For the COS observations, we ask for a different FP-POS in each orbit. There are no time constraints on the observations, and the visits can be scheduled separately. 17720( 4) - 24-Oct-2024 19:39:45 - [ 2] ------------------------------------------------------------------------------------ 17720( 4) - 24-Oct-2024 19:39:45 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ZTFJ2008+444 STAR, POLAR RA=20H08M32.7891S +/- 0.0001136 J2000 V = 18.8 Galex FUV 17.9 9 ", DEC=+44D49'39.67" +/- 0.0001307" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016.0 3.023936055314497E-4 0.001328 0.0029149 ------------------------------------------------------------------------------------------------------------------------------------ 17720( 4) - 24-Oct-2024 19:39:45 - [ 4] 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 ZTFJ2008+44 COS/FUV ACQ/PEA PSA G140L 1105 1 59 S (59 49 KXD S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939816 ------------------------------------------------------------------------------------------------------------------------------------ 2 ZTFJ2008+44 COS/FUV ACQ/PEA PSA G140L 1105 NUM-POS=5, STEP-SIZE=0.9, 1 59 S (59 49 KD CENTER=FLUX-WT-FLR S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939816 ------------------------------------------------------------------------------------------------------------------------------------ 3 ZTFJ2008+44 COS/FUV TIME-TA PSA G140L 800 FP-POS=1, BUFFER-TIME=6200 1 1722 S 49 G (1722 S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939817 ------------------------------------------------------------------------------------------------------------------------------------ 17720( 4) - 24-Oct-2024 19:39:45 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 4 ZTFJ2008+44 COS/FUV TIME-TA PSA G140L 800 FP-POS=1, BUFFER-TIME=6200 1 2605 S 49 G (2605 S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939815 ------------------------------------------------------------------------------------------------------------------------------------ 5 ZTFJ2008+44 COS/FUV TIME-TA PSA G140L 800 FP-POS=2, BUFFER-TIME=6200 1 2605 S 49 G (2605 S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939815 ------------------------------------------------------------------------------------------------------------------------------------ 6 ZTFJ2008+44 COS/FUV TIME-TA PSA G140L 800 FP-POS=3, BUFFER-TIME=6200 1 2605 S 49 G (2605 S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939815 ------------------------------------------------------------------------------------------------------------------------------------ 7 ZTFJ2008+44 COS/FUV TIME-TA PSA G140L 800 FP-POS=4, BUFFER-TIME=6200 1 2605 S 49 G (2605 S) Comments: As there could be some cyclotron emission in the FUV, the emission itself could be up to a magnitude brighter. We therefore run the ETC with the normalization magnitude smaller by 1 to check that the local cout rate is ok. Also, we included the brightest emission lines that we can expect from previous COS observations of polars. ETC number: 1939815 ------------------------------------------------------------------------------------------------------------------------------------ 17720( 4) - 24-Oct-2024 19:39:45 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ ZTFJ2008+4449 1 COS/FUV ACQ/PEA PSA G140L 1105 none none none none 1 N/A KXD ZTFJ2008+4449 2 COS/FUV ACQ/PEA PSA G140L 1105 none none none none 1 N/A KD ZTFJ2008+4449 3 COS/FUV TIME-TA PSA G140L 800 none none none none 1 N/A G ZTFJ2008+4449 4 COS/FUV TIME-TA PSA G140L 800 none none none none 2 N/A G ZTFJ2008+4449 5 COS/FUV TIME-TA PSA G140L 800 none none none none 3 N/A G ZTFJ2008+4449 6 COS/FUV TIME-TA PSA G140L 800 none none none none 4 N/A G ZTFJ2008+4449 7 COS/FUV TIME-TA PSA G140L 800 none none none none 5 N/A G 17720( 4) - 24-Oct-2024 19:39:45 - [ 7] Visit: 02 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 ZTFJ2008+44 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 21 S (21 49 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 ZTFJ2008+44 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1096 1 1998 S 49 -MAMA G (1998 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 ZTFJ2008+44 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1096 1 2641 S 49 -MAMA G (2641 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 ZTFJ2008+44 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1096 1 2616 S 49 -MAMA G (2616 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 ZTFJ2008+44 STIS/NUV TIME-TA 52X2 G230L 2376 BUFFER-TIME=1096 1 2616 S 49 -MAMA G (2616 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 | ------------------------------------------------------------------------------------------------------------------------------------ ZTFJ2008+4449 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A ZTFJ2008+4449 2 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 1 N/A -MAMA G ZTFJ2008+4449 3 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 2 N/A -MAMA G ZTFJ2008+4449 4 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 3 N/A -MAMA G ZTFJ2008+4449 5 STIS/NUV TIME-TA 52X2 G230L 2376 none none none none 4 N/A -MAMA G 17720( 4) - 24-Oct-2024 19:39:45 - [ 8] Summary Form for Proposal 17720 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X2, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, ACQ/PEAKD, ACQ/PEAKXD, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=1096, BUFFER-TIME=6200, CENTER=FLUX-WT-FLR, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, NUM-POS=5, STEP-SIZE=0.9 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names ZTFJ2008+4449 ------------------------------------------------------------------------------------------------------------------------------------