18018( 4) - 14-Aug-2025 16:17:15 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 18018 Version: 4 Check-in Time: 14-Aug-2025 16:17:15 STScI Edit Number: 0 Title Phoenix from the Ashes: Searching for Surviving Companions to SN~2023bee with early excess ------------------------------------------------------------------------------------ Type Cycle GO 33 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Qinan Wang Massachusetts Institute of Technology Y CoI: Dr. Armin Rest Space Telescope Science Institute N CoI: Dr. Ori Dosovitz Fox Space Telescope Science Institute N CoI: Dr. Justin Pierel Space Telescope Science Institute N CoI: Mike Engesser Space Telescope Science Institute N CoI: Prof. David J. Sand University of Arizona N CoI: Dr. Ryosuke Hirai Monash University N CoI: Prof. Griffin Hosseinzadeh University of California - San Diego N CoI: Dr. Charles Kilpatrick Northwestern University N CoI: Yuan Qi Ni University of Toronto N CoI: Dr. Georgios Dimitriadis Lancaster University N CoI: Dr. Matthew Ryan Siebert Space Telescope Science Institute N CoI: Dr. Jacob Jencson California Institute of Technology N CoI: Dr. Sebastian Gomez University of Texas at Austin N CoI: Dr. Yossef Zenati The Johns Hopkins University N CoI: Dr. Melissa Shahbandeh Space Telescope Science Institute N CoI: Dr. Louis-Gregory Strolger Space Telescope Science Institute N CoI: Dr. Suvi Gezari Space Telescope Science Institute N CoI: Muryel Guolo The Johns Hopkins University N CoI: Dr. James M DerKacy Space Telescope Science Institute N CoI: Prof. Ryan Foley University of California - Santa Cruz N CoI: Dr. Tea Temim Columbia University in the City of New N York ------------------------------------------------------------------------------------ Abstract Despite their important role in modern cosmology, the exact progenitor system of Type Ia supernovae (SNe Ia) remains elusive. The community has been trying to resolve this question in many indirect ways, but HST offers a unique opportunity to do so directly by observing a nearby SN Ia, SN 2023bee. This supernova has an early excess flux that could be due to the interaction between the SN ejecta and a non-degenerate companion. If observed, this would be the first direct detection of the single-degenerate SN Ia progenitor channel. According to theoretical models, the surviving non-degenerate companion will be heated by SN ejecta and inflate, resulting in a significant increase in its luminosity. The late-time bolometric light curves of SNe Ia are also indicative of their isotope composition, and thus of their progenitor systems. HST, with its exquisite depth, resolution, and multi-band coverage from UV to NIR, is the only resource suitable for discovering these heated surviving companions and constraining the progenitor channels of SNe Ia. Using HST to observe SN 2023bee over three cycles, we will be able to confirm or exclude the existence of a non-degenerate companion in this system, and provide strong constraints on the progenitor system. ------------------------------------------------------------------------------------ 18018( 4) - 14-Aug-2025 16:17:15 - [ 2] Observations Description ------------------------ We propose to observe SN 2023bee with 3 orbits in 5 filters: 1st orbit with F336W only, 2nd orbit with F606W & F814W, and 3rd orbit with F110W and F160W. The target is distant from the host galaxy and has a relatively clear background, so we do not worry much about the resolution or the exact location of the target. For first orbit we choose to do a straightforward CR split as it uses single filter. For second orbit we choose to do a 3-point dither with 2 filters. The order of filters is chosen to minimize the overhead time. For third orbit we choose to do similar 3-point dither with 2 NIR filters. The three orbits should be around Oct-Dec 2025, ideally 3 continuous orbits or at least close to each other. ------------------------------------------------------------------------------------ 18018( 4) - 14-Aug-2025 16:17:15 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN-2023BEE EXT-STAR, SUPERNOVA RA=08H56M11.6280S, J2000 V = 26 TYPE IA DEC=-03D19'32.05" Reference Frame: Other: NED Extended: NO Comments: This object was generated by the targetselector and retrieved from the NED database. ------------------------------------------------------------------------------------------------------------------------------------ 18018( 4) - 14-Aug-2025 16:17:15 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 18018( 4) - 14-Aug-2025 16:17:15 - [ 5] Visit: 03 (all) Visit Requirements: BETWEEN 10-OCT-2025:00:00:00 AND 28-DEC-2025:00:00:00 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 SN-2023BEE WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=STEP50 1 DEF CUM (449.234 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2023BEE WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=STEP50 1 DEF POS TARG 0.451, 0.403 CUM (449.234 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2023BEE WFC3/IR MULTIAC IR F110W NSAMP=11, SAMP-SEQ=STEP50 1 DEF POS TARG 0.474, 0.424 CUM (299.232 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SN-2023BEE WFC3/IR MULTIAC IR F110W NSAMP=11, SAMP-SEQ=STEP50 1 DEF POS TARG 0.925, 0.827 CUM (299.232 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN-2023BEE WFC3/IR MULTIAC IR F110W NSAMP=11, SAMP-SEQ=STEP50 1 DEF POS TARG 1.376, 1.230 CUM (299.232 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 SN-2023BEE WFC3/IR MULTIAC IR F160W NSAMP=14, SAMP-SEQ=STEP50 1 DEF POS TARG 0.902, 0.806 CUM (449.234 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F336W FLASH=21 1 565 S PATTERN 1 7 S 1C-SUB (2260 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F606W FLASH=14 1 153 S (153 POS TARG 0, 0 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 9 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F814W FLASH=14 1 308 S (308 POS TARG 0, 0 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 10 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F814W FLASH=14 1 308 S (308 POS TARG .092, .098 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 11 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F606W FLASH=14 1 153 S (153 POS TARG .092, .098 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 12 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F606W FLASH=14 1 153 S (153 POS TARG .185, .197 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 18018( 4) - 14-Aug-2025 16:17:15 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 13 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F814W FLASH=14 1 308 S (308 POS TARG .185, .197 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 14 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F814W FLASH=14 1 308 S (308 POS TARG .276, .294 S 1C-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 15 SN-2023BEE WFC3/UVI ACCUM UVIS2-C1K F606W FLASH=14 1 153 S (153 POS TARG .276, .294 S 1C-SUB 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2023BEE 1 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM SN-2023BEE 2 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM SN-2023BEE 3 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM SN-2023BEE 4 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM SN-2023BEE 5 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM SN-2023BEE 6 WFC3/IR MULTIAC IR F160W none none none none 1 N/A CUM SN-2023BEE 7 WFC3/UVI ACCUM UVIS2-C1 F336W 1 none none none 2 N/A S K1C-SUB SN-2023BEE 7 WFC3/UVI ACCUM UVIS2-C1 F336W 2 none none none 2 N/A S K1C-SUB SN-2023BEE 7 WFC3/UVI ACCUM UVIS2-C1 F336W 3 none none none 2 N/A S K1C-SUB SN-2023BEE 7 WFC3/UVI ACCUM UVIS2-C1 F336W 4 none none none 2 N/A S K1C-SUB SN-2023BEE 8 WFC3/UVI ACCUM UVIS2-C1 F606W none none none none 3 N/A S K1C-SUB SN-2023BEE 9 WFC3/UVI ACCUM UVIS2-C1 F814W none none none none 3 N/A S K1C-SUB SN-2023BEE 10 WFC3/UVI ACCUM UVIS2-C1 F814W none none none none 3 N/A S K1C-SUB SN-2023BEE 11 WFC3/UVI ACCUM UVIS2-C1 F606W none none none none 3 N/A S K1C-SUB SN-2023BEE 12 WFC3/UVI ACCUM UVIS2-C1 F606W none none none none 3 N/A S K1C-SUB SN-2023BEE 13 WFC3/UVI ACCUM UVIS2-C1 F814W none none none none 3 N/A S K1C-SUB 18018( 4) - 14-Aug-2025 16:17:15 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN-2023BEE 14 WFC3/UVI ACCUM UVIS2-C1 F814W none none none none 3 N/A S K1C-SUB SN-2023BEE 15 WFC3/UVI ACCUM UVIS2-C1 F606W none none none none 3 N/A S K1C-SUB 18018( 4) - 14-Aug-2025 16:17:15 - [ 8] Summary Form for Proposal 18018 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR, UVIS2-C1K1C-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FLASH=14, FLASH=21, NSAMP=11, NSAMP=14, SAMP-SEQ=STEP50 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 10-OCT-2025:00:00:00 AND 28-DEC-2025:00:00:00, PATTERN 1 7, POS TARG .092, .098, POS TARG .185, .197, POS TARG .276, .294, POS TARG 0, 0, POS TARG 0.451, 0.403, POS TARG 0.474, 0.424, POS TARG 0.902, 0.806, POS TARG 0.925, 0.827, POS TARG 1.376, 1.230 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F336W, F606W, F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN-2023BEE ------------------------------------------------------------------------------------------------------------------------------------