final 97436022 Assigned ID: 6789 ----- Attempting Submission 1 (Thu Apr 10 22:33:34 GMT 2025) ----- HST Phase I Proposal 6789 successfully submitted. Receipt: # 6789-1 ----- Attempting Submission 2 (Fri Apr 11 00:00:23 GMT 2025) ----- Here's my updated resubmission and any feedback or comments are welcome. Aug 13 1363258582 ----- Attempting Submission 1 (Fri Aug 08 20:37:29 GMT 2025) ----- HST Phase II Proposal 18018 successfully submitted. Receipt: # 18018-1 ----- Attempting Submission 2 (Tue Aug 12 20:21:40 GMT 2025) ----- ----- Attempting Submission 3 (Wed Aug 13 20:22:00 GMT 2025) ----- 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. 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. Dr. Qinan Wang is an expert in supernova photometry and spectroscopy with a focus on the rapid early features of SNe Ia and CCSNe. He has extensive experience on transients alert, coordinating follow-up with ground-based and space-based telescopes, data reduction and light curve fitting. Dr. Armin Rest is an expert in transient science, in particular SN Ia cosmology, light echoes of historic SN, and exotic transients. His technical expertise lies in data reduction, image analysis, photometry, and their application to wide-field time-domain surveys. Dr. Ori Fox is an expert in transient science and mid-IR observations of dust, in particular. He is a member of the JWST MIRI team and will support data analysis and interpretation. Dr. Justin Pierel is an expert in NIR supernova photometry, light curve fitting, and classification using HST and JWST. He has produced many of the existing NIR models currently used for simulations and fitting of NIR transients, including the SALT3-NIR model used for NIR standardization of SNeIa. He has also led multiple efforts to produce large scale simulations of SNIa surveys with the industry standard SNANA software, which is used to understand selection effects and perform bias-corrected cosmological measurements. Dr. Melissa Shahbandeh is an expert in IR spectroscopy and observations of transients, as well as JWST data analysis. She is experienced with modeling dust evolution in SNe. She is the PI and co-I of many programs using both ground and space-based telescopes, and thus can support supplementary multiwavelength observations. Mike Engesser is an expert in image reduction and analysis with JWST, near- and mid-infrared detectors, as well as detecting transients using modern alignment, subtraction, source detection, and photometry techniques. Dr. Ryan Foley in an expert in spectroscopic reductions of SNe. He is also an expert in the physics of SNe and SN Ia cosmology Yuan Qi Ni is an expert in SN Ia and their progenitors. Dr. Siebert is an expert in spectroscopy of all types of SNe Dr. Jacob Jencson is an expert in transient science, particularly in infrared studies of obscured or dusty transients. He has worked on several transient searches, including ones with Spitzer and HST, and has experience in reduction/analysis of spectroscopic and imaging data. Dr. Sebastian Gomez is an expert on the study of exotic transients, particularly superluminous supernovae and tidal disruption events. He has experience leading programs on optical photometric and spectroscopic observations of transients from a wide array of telescopes including HST, Magellan, MMT, Gemini, and WHT. Dr. Dave Coulter is an expert in optical/ir studies of kilonovae, em/gw search analysis and optimization, photometric data reduction, software/web application/database architecture and engineering Dr. Yossef Zenati is an expert on theory and simulation of transients, type Ia SNe and exotic SNe such as SESN. He is also a member of the few groups at the STScI. He will help with the simulation and interpretation of the data of these exotic SNe. Dr. Melissa Shahbandeh is an expert in IR spectroscopy and observations of transients, as well as JWST data analysis. She is experienced with modeling dust evolution in SNe. She is the PI and co-I of many programs using both ground and space-based telescopes, and thus can support supplementary multiwavelength observations. Dr. Lou Strolger is an expert in supernova rates, progenitor studies, and SN Ia cosmology. His technical expertise lies in data reduction and analysis, photometry, and spectroscopy. Dr. Suvi Gezari is an expert in time domain astronomy, in particular nuclear transients related to massive black holes. She has extensive experience characterizing transients in wide-field surveys in the optical and ultraviolet. Dr. Dimitriadis is an expert in image analysis and photometry, and interested in the physics and progenitors of all types of SNe. Muryel Guolo is an expert in time-domain astronomy. Dr. Tea Temim is an expert in the evolution of supernova remnants and particularly dust production and processing in supernovae and supernova remnants. As a former member of the MIRI team, she also has extensive experience with the reduction and analysis of JWST observations. Dr. Michael Fausnaugh is an expert in supernova photometry and spectroscopy with a focus on the rapid early features of SNe Ia and CCSNe. He has extensive experience analyzing the SNe in TESS. Dr. James Derkacy is an expert in supernova spectroscopy; including reductions, analysis and NLTE modeling. Stellar Physics and Stellar Types 6 false false false false false false SUPPORTED EXT-STAR SUPERNOVA TYPE IA NO This object was generated by the targetselector and retrieved from the NED database. J2000 J2000 WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F110W WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F814W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false 1755116425580 /private/var/folders/w_/hyfkyntj02s_3xtw61hfztxw0000gn/T/OPVisit5001459020147697671.xml The scheduling data was generated by CASM 33.1. CASM was run in Phase II mode. 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