15273( 4) - 11-Jul-2019 13:20:26 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15273 Version: 4 Check-in Time: 11-Jul-2019 13:20:26 STScI Edit Number: 0 Title A Star at the Limit? - Direct Mass Measurement of the White Dwarf in Nova Herculis 1991 ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Peter M. Garnavich University of Notre Dame Y CoI: Mr. Colin Littlefield University of Notre Dame N CoI: Mr. Mark Kennedy University College Cork N ------------------------------------------------------------------------------------ Abstract V838 Her was one of the fastest fading novae ever observed. Its nebular spectrum revealed unusual abundance ratios including a high sulfur content. These observations strongly imply that the white dwarf in the system is very close to the Chandrasekhar limit and may be the most massive known. However, no direct radial velocity measurements have confirmed this assertion. Our attempt to directly measure the mass was foiled by the light of very nearby stars contaminating the nova spectra and suppressing the estimated orbital velocity of the donor star. We propose STIS high-angular resolution spectroscopy to eliminate any contamination and make a definitive, trustworthy mass measurement for the V838~Her white dwarf. ------------------------------------------------------------------------------------ Observations Description ------------------------ We propose time-resolved spectroscopy of V838 Her with the STIS covering one binary orbit. Because the orbit is 7.1 hours long and the target visibility is 54 minutes, we will break the observations up into two visits. The first visit will be 5 HST orbits and cover an entire binary orbit. The second visit will be timed to fill in holes in phase created by the Earth occultations in the first visit. By coincidence, actually observing 9 consecutive orbits would naturally fill in the gaps, but such long periods of continuous observing are not commonly available. We have calculated that starting the second visit 63 HST orbits (4.2 days) after the beginning of the first visit will also fill all the missing phases. Longer delays (121, 130, 188 ... HST orbits) before starting the second visit will also work. V838 Her has a brightness of R=19.0 mag. This is too faint for the medium resolution gratings, but good signal-to-noise ratio (SNR) can be achieved with the low resolution grat- ing. Because the velocity amplitude is expected to be large, we will still achieve sufficient velocity resolution to measure the WD mass. We plan to use the 0.1 arcsec wide slit to improve the resolution while not significantly impacting the throughput. The narrow slit is critical for absorption line measurements because it maximizes spectral purity. To avoid the emission lines from the disk that dominate the blue wavelengths, we will use the G750L grating and cover 530-1000 nm. This will include the strong NaI line as well as hundreds of weaker absorption lines found in K-type stars. These weak lines are important for the cross-correlation velocity 15273( 4) - 11-Jul-2019 13:20:26 - [ 2] measurement method. To reduce fringing beyond 700 nm we will take contemporaneous fringe flats that add 2 minutes of overhead. With the G750L grating and 0.1-arcsec slit we will achieve a velocity resolution of 400 km/s. Using the cross-correlation technique, the velocity uncertainty per spectrum will be 35 km/s or an unbiased velocity amplitude good to 5% . The STIS ETC shows that we will reach a S/N= 13 per resolution element in a 900 sec exposure on the 19.0 mag star. Because of the multiplexing from cross-correlation this will be sufficient S/N to make an accurate velocity measurement. ------------------------------------------------------------------------------------ 15273( 4) - 11-Jul-2019 13:20:26 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V838HER STAR, CLASSICAL NOVA, RA=18H46M31.4700S +/- 0.09", J2000 V = 19.5 +/- 0.3 INTERACTING BINARY, K DEC=+12D14'2.26" +/- 0.14" V-IV Reference Frame: ICRS Extended: NO Comments: The position was determined from the GSC2 catalog. A plate solution was determined on a VATT image taken in 2016 and applied to the nova. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR-A-OFFSE EXT-STAR, K V-IV RA=18H46M31.5725S +/- 0.2", J2000 V = 18.8 +/- 0.1 T DEC=+12D14'0.99" +/- 0.2" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 15273( 4) - 11-Jul-2019 13:20:26 - [ 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 V838HER STIS/CCD ACQ F28X50LP MIRROR 1 25 S (25 S) Comments: Initial exposure for V=20 mag target, spectrum = K4V ------------------------------------------------------------------------------------------------------------------------------------ 2 V838HER STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 60 S (60 K S) Comments: Exposure through 0.1 arcsec slit for V=20 mag target, spectrum = K4V ------------------------------------------------------------------------------------------------------------------------------------ 3 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1280 S SAME POS AS 2 see below (1318 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1402 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1402 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 15273( 4) - 11-Jul-2019 13:20:26 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 12 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 13 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 14 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 15 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1352 S) ------------------------------------------------------------------------------------------------------------------------------------ 16 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 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 | ------------------------------------------------------------------------------------------------------------------------------------ V838HER 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V838HER 2 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 1 N/A K V838HER 3 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 1 659.0 S V838HER 3 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 1 659.0 S CCDFLAT 4 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 1 N/A CCDFLAT 4 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 1 N/A V838HER 5 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 2 676.0 S V838HER 5 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 2 676.0 S V838HER 6 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 2 676.0 S V838HER 6 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 2 676.0 S CCDFLAT 7 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 2 N/A CCDFLAT 7 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 2 N/A V838HER 8 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 3 701.0 S V838HER 8 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 3 701.0 S V838HER 9 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 3 701.0 S V838HER 9 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 3 701.0 S CCDFLAT 10 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 3 N/A CCDFLAT 10 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 3 N/A V838HER 11 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 4 676.0 S V838HER 11 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 4 676.0 S V838HER 12 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 4 676.0 S V838HER 12 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 4 676.0 S CCDFLAT 13 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 4 N/A CCDFLAT 13 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 4 N/A 15273( 4) - 11-Jul-2019 13:20:26 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V838HER 14 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 5 676.0 S V838HER 14 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 5 676.0 S V838HER 15 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 5 676.0 S V838HER 15 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 5 676.0 S CCDFLAT 16 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 5 N/A CCDFLAT 16 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 5 N/A 15273( 4) - 11-Jul-2019 13:20:26 - [ 7] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Have removed "after" restriction since Visit 01 completed 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 STAR-A-OFFS STIS/CCD ACQ F28X50LP MIRROR 1 15 S (15 ET S) Comments: Initial exposure for V=20 mag target, spectrum = K4V ------------------------------------------------------------------------------------------------------------------------------------ 2 V838HER STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 60 S (60 K S) Comments: Exposure through 0.1 arcsec slit for V=20 mag target, spectrum = K4V ------------------------------------------------------------------------------------------------------------------------------------ 3 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1280 S SAME POS AS 2 see below (1236 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1283 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1284 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1283 S) ------------------------------------------------------------------------------------------------------------------------------------ 9 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1284 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 S) ------------------------------------------------------------------------------------------------------------------------------------ 11 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1332 S) ------------------------------------------------------------------------------------------------------------------------------------ 15273( 4) - 11-Jul-2019 13:20:26 - [ 8] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 V838HER STIS/CCD ACCUM 52X0.1 G750L 7751 1 1200 S SAME POS AS 2 see below (1333 S) ------------------------------------------------------------------------------------------------------------------------------------ 13 CCDFLAT STIS/CCD ACCUM 0.2X0.06 G750L 7751 2 DEF (0 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 | ------------------------------------------------------------------------------------------------------------------------------------ STAR-A-OFFSET 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V838HER 2 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 1 N/A K V838HER 3 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 1 618.0 S V838HER 3 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 1 618.0 S CCDFLAT 4 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 1 N/A CCDFLAT 4 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 1 N/A V838HER 5 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 2 641.0 S V838HER 5 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 2 642.0 S V838HER 6 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 2 642.0 S V838HER 6 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 2 642.0 S CCDFLAT 7 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 2 N/A CCDFLAT 7 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 2 N/A V838HER 8 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 3 641.0 S V838HER 8 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 3 642.0 S V838HER 9 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 3 642.0 S V838HER 9 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 3 642.0 S CCDFLAT 10 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 3 N/A CCDFLAT 10 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 3 N/A V838HER 11 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 4 666.0 S V838HER 11 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 4 666.0 S V838HER 12 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 1 4 667.0 S V838HER 12 STIS/CCD ACCUM 52X0.1 G750L 7751 none none none 2 4 666.0 S CCDFLAT 13 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 1 none 4 N/A CCDFLAT 13 STIS/CCD ACCUM 0.2X0.06 G750L 7751 none none 2 none 4 N/A 15273( 4) - 11-Jul-2019 13:20:26 - [ 9] Summary Form for Proposal 15273 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.2X0.06, 52X0.1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SAME POS AS 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names CCDFLAT, STAR-A-OFFSET, V838HER ------------------------------------------------------------------------------------------------------------------------------------