14844( 3) - 28-Oct-2016 18:17:30 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14844 Version: 3 Check-in Time: 28-Oct-2016 18:17:30 STScI Edit Number: 0 Title Dust to Dust: Monitoring the Evolution of a New Class of Self-Obscured Transients ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Chris S. Kochanek The Ohio State University Y CoI: Mr. Scott Adams California Institute of Technology N ------------------------------------------------------------------------------------ Abstract The goal of this proposal is to understand a new class of explosive transients associated with the most massive AGB stars. Today these sources are true creatures of the mid-IR, being optically invisible and very faint in the near-IR. By coarsely monitoring them with Spitzer and HST we can examine the evolution of the luminosity, dust optical depth and dust radius/temperature at a key time when their observed fluxes are approaching those of the two known progenitors. At its very simplest, if they do not stop fading in the mid-IR or start to brighten in the near-IR, then they are almost certainly examples of the theoretically expected but observationally missing electron capture supernovae (ecSNe). The exciting result from the last set of HST/Spitzer observations is that the sources continued to fade and two are clearly substantially fainter than their progenitors. If this continues, the ecSNe interpretation becomes far stronger. ------------------------------------------------------------------------------------ Observations Description ------------------------ The newly recognized SN2008S class of transients consists of some form of explosive transient, possibly an electron capture supernova, on heavily self-obscured ~10Msun extreme AGB stars. After the transient they again cloak themselves with dust to be almost invisible in the near-IR while remaining very luminous in the mid-IR. The only way to determine their true natures is to continue following their evolution. We have allocated Spitzer time to follow their evolution, but the mid-IR data is not sensitive to the evolution of the dust optical depth. We propose observing 2 of these systems with WFC3/IR in the YJ (F110W) and H (F160W) bands. The near-IR emission comes from the underlying source (an expanding shock and/or a surviving star) and is absorbed by the surrounding dust, so the near-IR fluxes are exponentially sensitive to the evolution of the dust optical depth. For example, the optical depth from the observer through a dusty wind down to an expanding shock drops inversely with time, so we should begin to see these sources become brighter 14844( 3) - 28-Oct-2016 18:17:30 - [ 2] in the near-IR. ------------------------------------------------------------------------------------ 14844( 3) - 28-Oct-2016 18:17:30 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2008S STAR, SUPERNOVA RA=20H34M45.3300S, J2000 V = 26 DEC=+60D05'58.40" Reference Frame: ICRS Comments: copied from previous HST observation phase 2 APT ------------------------------------------------------------------------------------------------------------------------------------ 4 NAME-NGC-300 STAR, SUPERNOVA RA=00H54M34.1600S, J2000 V = 28 -OT2008-1 DEC=-37D38'28.60" Reference Frame: ICRS Comments: copied from previous HST observation phase 2 APT ------------------------------------------------------------------------------------------------------------------------------------ 14844( 3) - 28-Oct-2016 18:17:30 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE-3PT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.605 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 14844( 3) - 28-Oct-2016 18:17:30 - [ 5] Visit: 01 Visit Requirements: ORIENT 17.8D TO 74.4 D; ORIENT 107.8D TO 164.4 D; ORIENT 197.8D TO 254.4 D; ORIENT 287.8D TO 344.4 D 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-2008S WFC3/IR MULTIAC IR F160W NSAMP=11, SAMP-SEQ=STEP100 1 DEF PATTERN 1 1-2 CUM (1497.696 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SN-2008S WFC3/IR MULTIAC IR F110W NSAMP=9, SAMP-SEQ=STEP100 1 DEF CUM (897.694 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SN-2008S WFC3/IR MULTIAC IR F110W NSAMP=10, SAMP-SEQ=STEP100 1 DEF CUM (399.232 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-2008S 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A CUM SN-2008S 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A CUM SN-2008S 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A CUM SN-2008S 2 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A CUM SN-2008S 2 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A CUM SN-2008S 2 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A CUM SN-2008S 3 WFC3/IR MULTIAC IR F110W none none none none 1 N/A CUM 14844( 3) - 28-Oct-2016 18:17:30 - [ 6] Visit: 02 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 NAME-NGC-30 WFC3/IR MULTIAC IR F160W NSAMP=11, SAMP-SEQ=STEP100 1 DEF PATTERN 1 1-2 0-OT2008-1 CUM (1497.696 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 NAME-NGC-30 WFC3/IR MULTIAC IR F110W NSAMP=9, SAMP-SEQ=STEP100 1 DEF 0-OT2008-1 CUM (897.694 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NAME-NGC-30 WFC3/IR MULTIAC IR F110W NSAMP=8, SAMP-SEQ=STEP100 1 DEF 0-OT2008-1 CUM (199.231 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 | ------------------------------------------------------------------------------------------------------------------------------------ NAME-NGC-300-OT2008 1 WFC3/IR MULTIAC IR F160W 1 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 1 WFC3/IR MULTIAC IR F160W 2 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 1 WFC3/IR MULTIAC IR F160W 3 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 2 WFC3/IR MULTIAC IR F110W 1 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 2 WFC3/IR MULTIAC IR F110W 2 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 2 WFC3/IR MULTIAC IR F110W 3 none none none 1 N/A -1 CUM NAME-NGC-300-OT2008 3 WFC3/IR MULTIAC IR F110W none none none none 1 N/A -1 CUM 14844( 3) - 28-Oct-2016 18:17:30 - [ 7] Summary Form for Proposal 14844 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures IR ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/IR ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters NSAMP=10, NSAMP=11, NSAMP=8, NSAMP=9, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 107.8D TO 164.4 D, ORIENT 17.8D TO 74.4 D, ORIENT 197.8D TO 254.4 D, ORIENT 287.8D TO 344.4 D, PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NAME-NGC-300-OT2008-1, SN-2008S ------------------------------------------------------------------------------------------------------------------------------------