17764( 6) - 08-Aug-2025 21:08:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 17764 Version: 6 Check-in Time: 08-Aug-2025 21:08:44 STScI Edit Number: 1 Title Unraveling Red Supergiant Mass Loss with Early FUV Spectra of a Type IIP/L Supernova ------------------------------------------------------------------------------------ Type Cycle GO 32 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Kyra Azalee Bostroem University of Arizona Y CoI: Dr. Jennifer Andrews NOIRLab - Gemini North (HI) N CoI: Dr. Michael Jon Lundquist California Association for Research in N Astronomy (CARA) CoI: Prof. David J. Sand University of Arizona N CoI: Dr. Stefano Valenti University of California - Davis N CoI: Dr. Manisha Shrestha University of Arizona N CoI: Dr. Jacob Jencson California Institute of Technology N CoI: Prof. Griffin Hosseinzadeh University of California - San Diego N CoI: Jeniveve Pearson University of Arizona N CoI: Dr. Yize Dong Center for Astrophysics | Harvard & N Smithsonian CoI: Mr. Nicolas Eduardo Meza Retamal University of California - Davis N CoI: Emily Hoang University of California - Davis N CoI: Daryl Janzen University of Saskatchewan N CoI: Dr. Saurabh W. Jha Rutgers the State University of New Jersey N CoI: Dr. Aravind Pazhayath Ravi University of California - Davis N CoI: Ms. Darshana Mehta University of California - Davis N ------------------------------------------------------------------------------------ Abstract During the red supergiants phase, the progenitors of hydrogen-rich Type IIP/L supernovae undergo substantial mass loss. However, there is no first principle theory that predicts the mass-loss rate. Furthermore, prescriptions based on observations vary by orders of magnitude. Additionally, observations of supernovae during the early evolution, can show evidence of even higher mass-loss rates occurring just prior to explosion, although it is unknown what fraction of supernovae this occurs in. While optical spectra can detect the highest mass-loss rates via narrow high-ionization lines that disappear within 2 weeks of explosion, the ultraviolet is sensitive to the full range of possible mass loss, with the majority of strong resonance lines occurring in the far ultraviolet (FUV) as well as continuum emission from the ejecta's interaction with circumstellar material. In this way, FUV spectra can be used to characterize the density, location, and composition of the circumstellar material. Despite these strong indicators, only one Type IIP/L supernova has been observed in the FUV within a week of explosion. This is because only about one Type IIP/L supernova per year is discovered young, unextincted, and close enough for FUV study and these observations require a disruptive ToO to execute. We propose a disruptive ToO to obtain FUV and NUV observations of an infant, nearby, Type IIP/L supernova to understand the red supergiant mass loss and the diversity of supernovae in the UV. Beyond the local universe, these observations are critical for understanding the high redshift supernovae, which may be some of the first single objects observable in the early universe. 17764( 6) - 08-Aug-2025 21:08:44 - [ 2] ------------------------------------------------------------------------------------ Observations Description ------------------------ We will trigger this ToO on a Type II supernova that is UV bright and discovered within 24 hours of explosion. We would like the First visit to execute as soon as possible with the second visit executing a day later and the third visit a day after that. The final visit will execute 7 days after the last visit. We request a full GS acquisition at the beginning of each orbit as the supernova will change on the timescale of a day and thus these observations are not repeatable. ------------------------------------------------------------------------------------ 17764( 6) - 08-Aug-2025 21:08:44 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SN2025TIS EXT-STAR, SUPERNOVA, RA=03H55M22.7790S, J2000 V = 17 +/- 0.1 SUPERNOVA TYPE II DEC=-28D09'32.68" Reference Frame: ICRS Extended: NO ------------------------------------------------------------------------------------------------------------------------------------ 17764( 6) - 08-Aug-2025 21:08:44 - [ 4] Visit: 01 Visit Requirements: ON HOLD ; TOO RESPONSE TIME 2.0D On Hold Comments: Waiting for a suitable supernova to explode. I understand this response time is likely a lower limit on what STScI is capable of but the sooner the better for this program Additional Comments: Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed First epoch should be executed as soon as possible after trigger For SN with initial brightness around r=17 mag 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 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) NEW OBSET FULL ACQ ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) NEW OBSET FULL ACQ ------------------------------------------------------------------------------------------------------------------------------------ 6 SN2025TIS STIS/NUV ACCUM 52X0.2 G230L 2376 1 1400 S -MAMA (1400 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 SN2025TIS STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 180 S (180 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2025TIS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2025TIS 2 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 1 N/A -MAMA SN2025TIS 3 STIS/CCD ACQ F28X50LP MIRROR none none none none 2 N/A SN2025TIS 4 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 2 N/A -MAMA SN2025TIS 5 STIS/CCD ACQ F28X50LP MIRROR none none none none 3 N/A SN2025TIS 6 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 3 N/A -MAMA SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 3 N/A SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 3 N/A 17764( 6) - 08-Aug-2025 21:08:44 - [ 5] Visit: 02 Visit Requirements: AFTER 01 BY 18 H TO 28 H; ON HOLD On Hold Comments: Waiting for a suitable supernova to explode. Additional Comments: Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed Second epoch should be executed 24 hours after first visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 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 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) NEW OBSET FULL ACQ ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) NEW OBSET FULL ACQ ------------------------------------------------------------------------------------------------------------------------------------ 6 SN2025TIS STIS/NUV ACCUM 52X0.2 G230L 2376 1 1400 S -MAMA (1400 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 SN2025TIS STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 180 S (180 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2025TIS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2025TIS 2 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 1 N/A -MAMA SN2025TIS 3 STIS/CCD ACQ F28X50LP MIRROR none none none none 2 N/A SN2025TIS 4 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 2 N/A -MAMA SN2025TIS 5 STIS/CCD ACQ F28X50LP MIRROR none none none none 3 N/A SN2025TIS 6 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 3 N/A -MAMA SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 3 N/A SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 3 N/A 17764( 6) - 08-Aug-2025 21:08:44 - [ 6] Visit: 03 Visit Requirements: AFTER 02 BY 18 H TO 24 H; ON HOLD On Hold Comments: Waiting for a suitable supernova to explode. Additional Comments: Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed Third epoch should be executed 24 hours after second visit and 48 hours after first visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 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 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) NEW OBSET FULL ACQ ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2025TIS STIS/NUV ACCUM 52X0.2 G230L 2376 1 1300 S -MAMA (1300 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2025TIS STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 180 S (180 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2025TIS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2025TIS 2 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 1 N/A -MAMA SN2025TIS 3 STIS/CCD ACQ F28X50LP MIRROR none none none none 2 N/A SN2025TIS 4 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 2 N/A -MAMA SN2025TIS 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 2 N/A SN2025TIS 5 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 2 N/A 17764( 6) - 08-Aug-2025 21:08:44 - [ 7] Visit: 04 Visit Requirements: AFTER 03 BY 6 D TO 8 D; ON HOLD On Hold Comments: Waiting for a suitable supernova to explode. Additional Comments: Please put a full GS acq at the beginning of each orbit so if one orbit fails the others have a chance of succeeding. I can adjust the exposure times if needed fourth epoch should be executed 7 days after third visit For SN with initial brightness around r=17 mag If possible execute at same orientation as visit 1 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 SN2025TIS STIS/CCD ACQ F28X50LP MIRROR 1 5 S (5 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2000 S -MAMA (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2500 S NEW OBSET FULL ACQ -MAMA (2500 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 2500 S NEW OBSET FULL ACQ -MAMA (2500 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SN2025TIS STIS/FUV ACCUM 52X0.2 G140L 1425 1 850 S (850 NEW OBSET FULL ACQ -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 6 SN2025TIS STIS/NUV ACCUM 52X0.2 G230L 2376 1 740 S (740 -MAMA S) ------------------------------------------------------------------------------------------------------------------------------------ 7 SN2025TIS STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 200 S (200 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2025TIS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SN2025TIS 2 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 1 N/A -MAMA SN2025TIS 3 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 2 N/A -MAMA SN2025TIS 4 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 3 N/A -MAMA SN2025TIS 5 STIS/FUV ACCUM 52X0.2 G140L 1425 none none none none 4 N/A -MAMA SN2025TIS 6 STIS/NUV ACCUM 52X0.2 G230L 2376 none none none none 4 N/A -MAMA 17764( 6) - 08-Aug-2025 21:08:44 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 1 4 N/A SN2025TIS 7 STIS/CCD ACCUM 52X0.2E1 G430L 4300 none none none 2 4 N/A 17764( 6) - 08-Aug-2025 21:08:44 - [ 9] Summary Form for Proposal 17764 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, 52X0.2E1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 18 H TO 28 H, AFTER 02 BY 18 H TO 24 H, AFTER 03 BY 6 D TO 8 D, NEW OBSET FULL ACQ, ON HOLD , TOO RESPONSE TIME 2.0D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140L, G230L, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names SN2025TIS ------------------------------------------------------------------------------------------------------------------------------------