17123( 3) - 08-Dec-2022 14:42:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17123 Version: 3 Check-in Time: 08-Dec-2022 14:42:30 STScI Edit Number: 0 Title Characterizing four massive post-interaction binaries with HST/COS ------------------------------------------------------------------------------------ Type Cycle GO 30 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Ylva Goetberg Carnegie Institution of Washington Y CoI: Bethany Ann Ludwig University of Toronto N CoI: Maria Drout University of Toronto Y CoI: Dr. Nathan Smith University of Arizona N CoI: Dr. Selma E. de Mink Max Planck Institute for Astrophysics N CoI: Dr. Jose Groh University of Dublin, Trinity College N CoI: Mr. Eoin Farrell University of Dublin, Trinity College N ------------------------------------------------------------------------------------ Abstract Massive stars stripped of their hydrogen-rich envelopes should be one of the most common types of binary products and the progenitors of stripped-envelope supernovae and binary neutron star mergers. Yet, no such system descending directly from stable mass transfer has been published. We propose to characterize a set of four binaries containing ~2-5 Msun stripped stars (originating from stars with initial masses ~7-20 Msun) that orbit B-type companions and that were recently discovered in the Large Magellanic Cloud. Because stripped stars are the exposed helium cores of their progenitors, they are very hot and emit most of their light in the ionizing extreme ultraviolet. As a result, their main-sequence companions dominate the optical output, making HST/COS UV spectroscopy necessary for characterizing the properties of the stripped stars. Using a set of HeII and HI lines combined with NIV and NV lines in the UV, we will be able to measure the effective temperature, surface gravity, surface hydrogen/helium content, and wind mass loss. In turn, these will lead to estimates for the bolometric luminosity, stellar radius, and mass. Combined with the properties of the companion star, we will provide the first stringent constraints on the outcomes of stable mass transfer in massive binary stars. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program will obtain UV spectra for 4 targets in the LMC that are newly discovered double-lined spectroscopic binaries, where one of the components is an intermediate mass stripped helium star candidate. These stripped stars are hot stars that are more luminous than subdwarfs, but lack the wind emission lines of Wolf-Rayet stars. The goal is to obtain UV spectra that can be modeled to both obtain stellar parameters and to constrain their wind parameters. The UV is essential for this study both because the optical spectra are obscured by the companion main-sequence star and the UV contains valuable spectral lines sensitive to wind parameters. Spectra will be obtained in the FUV with the G140L grism and a center wavelength of 800 Angstrom, providing continuous wavelength coverage between ~900-1950 Angstrom. We use the maximum exposure time avalible in between 2-3 orbits allocated per star, using all four FP positions for each target. 17123( 3) - 08-Dec-2022 14:42:30 - [ 2] The impacts of a reduced gyro operations on this program would primarily be reduced schedualability due to the smaller field of regard, as well as possible impacts of roll angle constraints when avoiding placement of bright field objects in the second COS aperture. Slightly longer acquisition times would have only a small effect on the S/N of our observations. ------------------------------------------------------------------------------------ 17123( 3) - 08-Dec-2022 14:42:30 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LMC-OBS45465 EXT-STAR, ALGOL SYSTEM, RA=05H26M19.7633S +/- 0.0014", J2000 V = 18.66 +/- 0.11 UVW2: 17.87 (ABmag), -1066 COMPOSITE SPECTRAL DEC=-69D22'34.25" +/- 0.0017" UVM2: 17.93 (ABmag) TYPE, INTERACTING BINARY, SDO Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 2 LMC-OBS45522 EXT-STAR, ALGOL SYSTEM, RA=05H11M23.1388S +/- 0.0015", J2000 V = 18.41 +/- 0.086 UVW2: 17.47 -795 COMPOSITE SPECTRAL DEC=-69D53'53.59" +/- 0.0013" (ABmag), UVM2: 17.57 (ABmag) TYPE, SDO Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 3 LMC-OBS45570 EXT-STAR, ALGOL SYSTEM, RA=05H23M39.8466S +/- 0.0009", J2000 V = 17.94 +/- 0.028 UVW2: 17.09 -572 COMPOSITE SPECTRAL DEC=-68D36'41.02" +/- 0.0009" (ABmag), UVM2: 17.19 (ABmag) TYPE, SDO Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 4 LMC-OBS45473 EXT-STAR, ALGOL SYSTEM, RA=05H36M33.0762S +/- 0.0014", J2000 V = 18.18 +/- 0.10 UVW2: 17.67 (ABmag), -3515 COMPOSITE SPECTRAL DEC=-69D26'27.16" +/- 0.0016" UVM2: 17.76 (ABmag) TYPE, SDO Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 5 ACQUISITION- EXT-STAR, UNDESIGNATED RA=05H36M32.1513S +/- J2000 V = 17.09 +/- 0.082 UVW2: 17.73 STAR-3515 0.00007101734", (ABmag), UVM2: 17.49 (ABmag), UVW1: DEC=-69D26'34.05" +/- 17.61 (ABmag) 0.00007695555" Reference Frame: ICRS Extended: NO Comments: This star is to make the acquisition of target 4 easier. We aim to first point at this star, then offset the telescope to target 4 and obtain the spectrum of star 3. ------------------------------------------------------------------------------------------------------------------------------------ 17123( 3) - 08-Dec-2022 14:42:30 - [ 4] Visit: 01 (LMC-OBS45465-1066-COS) 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 LMC-OBS4546 COS/NUV ACQ/IMA PSA MIRRORB 1 21 S (21 5-1066 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 SEGMENT=A, FLASH=YES, 1 1290 S 5-1066 G FP-POS=1, BUFFER-TIME=4673 (1290 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 FP-POS=1, SEGMENT=A, 1 1290 S 5-1066 G FLASH=YES, BUFFER-TIME=4673 (1290 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 FP-POS=2, FLASH=YES, 1 1454 S 5-1066 G SEGMENT=A, BUFFER-TIME=4673 (1454 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 FP-POS=2, FLASH=YES, 1 1454 S 5-1066 G SEGMENT=A, BUFFER-TIME=4673 (1454 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 FP-POS=3, FLASH=YES, 1 1453 S 5-1066 G SEGMENT=A, BUFFER-TIME=4673 (1453 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 LMC-OBS4546 COS/FUV TIME-TA PSA G140L 800 FLASH=YES, FP-POS=4, 1 1453 S 5-1066 G SEGMENT=A, BUFFER-TIME=4673 (1453 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 | ------------------------------------------------------------------------------------------------------------------------------------ LMC-OBS45465-1066 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE LMC-OBS45465-1066 2 COS/FUV TIME-TA PSA G140L 800 none none none none 1 N/A G LMC-OBS45465-1066 3 COS/FUV TIME-TA PSA G140L 800 none none none none 1 N/A G LMC-OBS45465-1066 4 COS/FUV TIME-TA PSA G140L 800 none none none none 2 N/A G LMC-OBS45465-1066 5 COS/FUV TIME-TA PSA G140L 800 none none none none 2 N/A G LMC-OBS45465-1066 6 COS/FUV TIME-TA PSA G140L 800 none none none none 3 N/A G LMC-OBS45465-1066 7 COS/FUV TIME-TA PSA G140L 800 none none none none 3 N/A G 17123( 3) - 08-Dec-2022 14:42:30 - [ 5] Visit: 02 (LMC-OBS45522-795-COS) 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 LMC-OBS4552 COS/NUV ACQ/IMA PSA MIRRORB 1 15 S (15 2-795 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LMC-OBS4552 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, SEGMENT=A, 1 1276 S 2-795 G FLASH=YES, BUFFER-TIME=3866 see below (5474 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 | ------------------------------------------------------------------------------------------------------------------------------------ LMC-OBS45522-795 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE LMC-OBS45522-795 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1289.0 S G LMC-OBS45522-795 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 1 1289.0 S G LMC-OBS45522-795 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1448.0 S G LMC-OBS45522-795 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 2 1448.0 S G 17123( 3) - 08-Dec-2022 14:42:30 - [ 6] Visit: 03 (LMC-OBS45570-572-COS) 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 LMC-OBS4557 COS/NUV ACQ/IMA PSA MIRRORB 1 11 S (11 0-572 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LMC-OBS4557 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, FLASH=YES, 1 1276 S 0-572 G SEGMENT=A, BUFFER-TIME=3077 see below (5472 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 | ------------------------------------------------------------------------------------------------------------------------------------ LMC-OBS45570-572 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A GE LMC-OBS45570-572 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1293.0 S G LMC-OBS45570-572 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 1 1293.0 S G LMC-OBS45570-572 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1443.0 S G LMC-OBS45570-572 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 2 1443.0 S G 17123( 3) - 08-Dec-2022 14:42:30 - [ 7] Visit: 04 (LMC-OBS45473-3515-COS) 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 ACQUISITION COS/NUV ACQ/IMA PSA MIRRORB 1 23 S (23 -STAR-3515 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 LMC-OBS4547 COS/FUV TIME-TA PSA G140L 800 FP-POS=ALL, SEGMENT=A, 1 1276 S 3-3515 G FLASH=YES, BUFFER-TIME=4287 see below (5469 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 | ------------------------------------------------------------------------------------------------------------------------------------ ACQUISITION-STAR-35 1 COS/NUV ACQ/IMA PSA MIRRORB none none none none 1 N/A 15 GE LMC-OBS45473-3515 2 COS/FUV TIME-TA PSA G140L 800 none none none 1 1 1286.0 S G LMC-OBS45473-3515 2 COS/FUV TIME-TA PSA G140L 800 none none none 2 1 1287.0 S G LMC-OBS45473-3515 2 COS/FUV TIME-TA PSA G140L 800 none none none 3 2 1448.0 S G LMC-OBS45473-3515 2 COS/FUV TIME-TA PSA G140L 800 none none none 4 2 1448.0 S G 17123( 3) - 08-Dec-2022 14:42:30 - [ 8] Summary Form for Proposal 17123 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=3077, BUFFER-TIME=3866, BUFFER-TIME=4287, BUFFER-TIME=4673, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, FP-POS=ALL, SEGMENT=A ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, MIRRORB ------------------------------------------------------------------------------------------------------------------------------------ Target Names ACQUISITION-STAR-3515, LMC-OBS45465-1066, LMC-OBS45473-3515, LMC-OBS45522-795, LMC-OBS45570-572 ------------------------------------------------------------------------------------------------------------------------------------