0 Assigned ID: 2251 ----- Attempting Submission 1 (Fri Apr 09 21:08:21 GMT 2021) ----- HST Phase I Proposal 2251 successfully submitted. Receipt: # 2251-1 ----- Attempting Submission 2 (Fri Apr 09 23:28:31 GMT 2021) ----- HST Phase I Proposal 2251 successfully submitted. Receipt: # 2251-2 ----- Attempting Submission 3 (Mon Apr 12 15:35:11 GMT 2021) ----- For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. One of the orbits with STIS during visit 3 failed. I am therefore resubmitting another visit with the same specifics. -1257107434 ----- Attempting Submission 1 (Wed Jul 28 20:31:35 GMT 2021) ----- ----- Attempting Submission 2 (Sat Sep 04 00:58:16 GMT 2021) ----- ----- Attempting Submission 3 (Mon Dec 04 20:33:30 GMT 2023) ----- I am currently only resubmitting for STIS. The radius and magnetic field structure of the smallest white dwarf The white dwarf ZTF J1901+1458 is extreme in almost every regard: it rotates every 6.94 minutes, one of the shortest periods measured for an isolated white dwarf, it is threaded by a magnetic field of almost a billion Gauss, and is the smallest white dwarf for which a radius has been measured, with a size comparable to that of the Moon. The white dwarf is so compact, that it might be gravitationally unstable and headed toward collapse. The radius's measurement, however, hinges on assumptions on the white dwarf's spectral distribution that can only be verified by ultraviolet spectroscopy. Moreover, a UV spectrum will allow a detailed modeling of the white dwarf's magnetic field strength and morphology. The purpose of this program is to study the SED and lightcurve of the white dwarf ZTF J1901+1458, as well as detect hydrogen absorption features in the far UV. ZTF J1901+1458 is the smallest white dwarf known (with a radius of about 2100 km), which shows signs of a very strong magnetic fields (almost a billion Gauss) and a variation in optical luminosity of about 3% over a period of 6.94 minutes. The proposed observations will allow us to constrain the surface temperature and radius of the white dwarf, as well as its magnetic field strength and structure. We ask for 4 orbits of COS spectroscopy and 6 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, for a total of 4. There are no time constraints on the observations, and the 4 visits can be scheduled separately. The Swift UVOT data for this white dwarf in the UV shows a flattening of the SED, in contrast to what we expect from a non magnetized white dwarf. For this reason, we cannot predict with high confidence the luminosity in the far UV. Thus, we employ two different models in the ETC: a flat spectrum normalized to the bluest UVOT filter, which correspond to the faintest hypothesis for the far UV, and the white dwarf spectrum that best fits both the optical and UV data, which predicts a higher number of counts. To be the most conservative, we use the flat spectrum to estimate the exposure times in the targeting mode of COS, while we employ the white dwarf spectrum to estimate the correct buffer times and the exposure times in the targeting mode of STIS. Dr. Ilaria Caiazzo is a postdoctoral fellow at Caltech. She is an expert on high-energy astrophysics and the physics of white dwarfs, as well as in the analysis of white dwarf spectroscopy and photometry. Mr. Kevin Burdge is Caltech graduate student and is a leading expert in discovering short-period variable white dwarfs using wide field photometric surveys such as the Zwicky Transient facility. He has led HST spectroscopy proposals. Dr Boris Gaensicke is a professor at the University of Warwick. He is a world expert in white dwarf studies and has led several HST proposals. Dr. Jeremy Heyl is a professor of physics and astronomy at the University of British Columbia. He is an expert on galactic dynamics, white dwarfs, binary evolution and compact objects in general. Dr. Shrinivas Kulkarni is a professor at Caltech and PI of the Zwicky Transient Facility. He has been a pioneer in many fields, including millisecond pulsars, old neutron stars, young neutron stars, brown dwarfs, soft gamma-ray repeaters, supernova remnants, gamma-ray bursts, new types of optical transients and instrumentation. Dr. Harvey Richer is a professor at the University of British Columbia. He has led three very large proposals on HST looking for globular cluster white dwarfs and has recently authored a large paper on the search for massive white dwarfs using the Gaia database and Gemini spectroscopy. Dr. Tom Prince is a professor at Caltech and the director of the Keck Institute of Space Studies. He is an expert in several fields, including gravitational wave astrophysics, cosmic-rays, gamma-ray astronomy, high-performance computation and virtual observatories. Dr. Jim Fuller is a professor at Caltech and he is an expert in several fields, including stellar evolution and white dwarf physics Dr. Adela Kawka is a Senior Research Fellow at ICRAR-Curtin. Her research focuses on the properties and evolution of white dwarf stars and other evolved stars such as hot subdwarfs. Dr Stephane Vennes is a professor at the Australian National University. He is an expert on magnetic white dwarfs and he has successfully led a similar UV spectroscopic analysis on a rotating magnetized white dwarf to the one proposed here. Dr Lilia Ferrario is a professor at the Australian National University. She is an expert on magnetism in stars, especially magnetized white dwarfs. Dr Dayal Wickramasinghe is a professor at the Australian National University. He has been a pioneer in th theoretical studies of white dwarfs and in particular magnetic white dwarfs. Stellar Physics and Stellar Types 6 false false true false false false false false SUPPORTED STAR DA NO IPHAS-J190132.77+145807.6 GAIA-DR2-4506869128279648512 J2000 J2000 PS1 g 15.51, Swift U 14.94, Swift UVW1 14.42, Swift UVM2 14.40 COS/FUV Spectroscopic No No G140L 800 STIS/NUV-MAMA Spectroscopic No No G230L 2376 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1659448893000 139.8178303448601 (Tic-Visit :proposal-id 16753 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "03-Sep-2021 17:51:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1504656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2756 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1659523180000 138.717926271801 (Tic-Visit :proposal-id 16753 :visit-id "04" :proposal-version -1 :trans-version "20220516" :date "11-Aug-2022 17:14:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1504656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "04" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2756 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "04" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1663409135000 97.90658499926252 (Tic-Visit :proposal-id 16753 :visit-id "R4" :proposal-version -1 :trans-version "20220516" :date "11-Aug-2022 17:14:09.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 1504656 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "R4" :obset-id "R4" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "R4" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2756 :al-overhead-at-end 0 :internal-dur-at-end 95 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "R4" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 363 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 2 0 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1692410544000 121.57265803060432 (Tic-Visit :proposal-id 16753 :visit-id "02" :proposal-version -1 :trans-version "20210514" :date "03-Sep-2021 17:57:16.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 2000896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2756 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "02" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 603 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 3 0 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. 1694332211000 103.02124117405918 (Tic-Visit :proposal-id 16753 :visit-id "03" :proposal-version -1 :trans-version "20210514" :date "03-Sep-2021 17:57:32.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 2000896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 2756 :al-overhead-at-end 0 :internal-dur-at-end 178 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) (Tic-Orbit :proposal-id 16753 :visit-id "03" :orbit-number 3 :pcs-time 392 :si-vis-utilization 2757 :al-overhead-at-end 0 :internal-dur-at-end 603 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 3 0 The scheduling data was generated by CASM 31.1. CASM was run in Phase II mode. /private/var/folders/q5/pgd2_mqs78b2rc6c4f68fd900005mw/T/OPVisit2161217698143337723.xml (Tic-Visit :proposal-id 16753 :visit-id "R5" :proposal-version -1 :trans-version "20240604" :date "10-Jun-2024 14:38:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 574464 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16753 :visit-id "R5" :obset-id "R5" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16753 :visit-id "R5" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2635 :al-overhead-at-end 0 :internal-dur-at-end 440 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3015 :pcs-gap 0 ) true 1 0