17107( 6) - 14-Jun-2024 15:09:34 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17107 Version: 6 Check-in Time: 14-Jun-2024 15:09:34 STScI Edit Number: 4 Title A very low mass, highly irradiated survivor of the common envelope phase ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Prof. Boris T. Gaensicke The University of Warwick Y CoI: Prof. Tom R. Marsh The University of Warwick N CoI: Dr. Nicole Reindl Universitat Potsdam N CoI: Dr. Veronika Schaffenroth Thuringer Landessternwarte Tautenburg N (TLS) ------------------------------------------------------------------------------------ Abstract The common envelope (CE) phase is a key driver in the evolution of close binary stars, causing their periods to shrink dramatically, or the two stars to merge altogether. An important parameter for the survival of many systems, including planets enveloped by host giant branch stars, is the minimum companion mass that can survive a CE. No certain survivor of a CE has been found with a mass less than 50 Jupiter masses (M_J), well above the lowest theoretical prediction of 5 M_J. With the theory itself uncertain, it is important to establish firmer observational limits. A recently discovered hot white dwarf / brown dwarf binary with a period of 2.4 hours promises to do just this. Optical data of this system indicate a mass for the brown dwarf lying between 11 and 44 M_J. Better constraints require a measurement of the temperature of the hot white dwarf, which translates to a better mass for the brown dwarf through a combination of distance, model atmosphere, gravitational red-shift and dynamical constraints. Preliminary indications from optical spectra suggest a white dwarf temperature of order 100, 000 K and a brown dwarf mass of order 20 M_J, substantially reducing the current gap between theory and observation. However, optical spectra have relatively few and weak features compared to the FUV, and suffer significant contamination from light emitted by the heated face of the brown dwarf in this compact system. The aim of this proposal is to acquire FUV spectra to measure the white dwarf's effective temperature and to obtain improved values for the dynamical and red-shift constraints upon which the mass estimates hinge. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of this proposal is to obtain far-ultraviolet, orbital phase-resolved, high-resolution spectroscopy of WD 2003+0838 to measure the effective temperature and orbital velocity of the white dwarf, in order to determine its mass and hence the mass of its brown dwarf companion, and to look for evidence of mass loss and/or accretion in the system and circumstellar material. The observations will be split into 2 x 3 orbits, following standard STIS procedures: target acquisition with the F28X50LP long-pass filter, followed by E140M time-tag spectroscopy (such that we can bin the data into arbitrary phase bins during the analysis) using the 0.2"x0.2" aperture. The two visits can be 17107( 6) - 14-Jun-2024 15:09:34 - [ 2] scheduled totally independently. ------------------------------------------------------------------------------------ 17107( 6) - 14-Jun-2024 15:09:34 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 WDJ200328.97 STAR, DA RA=20H03M28.9775S +/- 0.0360", J2000 V = 14.1 +/- 0.05 GALEX NUV=13.5 +083847.22 DEC=+08D38'46.97" +/- 0.0219" Reference Frame: ICRS Extended: NO Comments: Coordinates and proper motions were taken from Gaia EDR3. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2016 2.035129224855774E-4 -0.015695 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 17107( 6) - 14-Jun-2024 15:09:34 - [ 4] Visit: 01 (Visit 1) 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 WDJ200328.9 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.5 S (0.5 7+083847.22 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to V=14.1 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2269 S 7+083847.22 -MAMA G see below (2147 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G see below (2600 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G see below (2600 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 17107( 6) - 14-Jun-2024 15:09:34 - [ 5] 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ200328.97+083847 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A .22 WDJ200328.97+083847 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2147.0 S .22 -MAMA G WDJ200328.97+083847 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2600.0 S .22 -MAMA G WDJ200328.97+083847 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2600.0 S .22 -MAMA G 17107( 6) - 14-Jun-2024 15:09:34 - [ 6] Visit: 02 (Visit 2) 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 WDJ200328.9 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.5 S (0.5 7+083847.22 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to V=14.1 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2269 S 7+083847.22 -MAMA G (2269 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G (2723 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G (2723 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ200328.97+083847 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A .22 WDJ200328.97+083847 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 N/A .22 -MAMA G 17107( 6) - 14-Jun-2024 15:09:34 - [ 7] 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ200328.97+083847 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 N/A .22 -MAMA G WDJ200328.97+083847 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 N/A .22 -MAMA G 17107( 6) - 14-Jun-2024 15:09:34 - [ 8] Visit: 52 (Visit 52) Visit Requirements: On Hold Comments: Additional Comments: HOPR repeat of visit 02. 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 WDJ200328.9 STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.5 S (0.5 7+083847.22 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to V=14.1 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 2 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2269 S 7+083847.22 -MAMA G see below (2147 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 3 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G see below (2600 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 4 WDJ200328.9 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=300 1 2723 S 7+083847.22 -MAMA G see below (2600 S) Comments: At the estimated Teff=100000K for the white dwarf in this binary, the spectrum will closely resemble a blackbody, hence we chose a blackbody with T=100000K and scaled it to GALEX NUV=13.5 for the STIS ETC calculation. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 17107( 6) - 14-Jun-2024 15:09:34 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ WDJ200328.97+083847 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A .22 WDJ200328.97+083847 2 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 1 2147.0 S .22 -MAMA G WDJ200328.97+083847 3 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 2 2600.0 S .22 -MAMA G WDJ200328.97+083847 4 STIS/FUV TIME-TA 0.2X0.2 E140M 1425 none none none none 3 2600.0 S .22 -MAMA G 17107( 6) - 14-Jun-2024 15:09:34 - [ 10] Summary Form for Proposal 17107 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=300 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names WDJ200328.97+083847.22 ------------------------------------------------------------------------------------------------------------------------------------