11637( 3) - 22-Jun-2009 11:51:36 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11637 Version: 3 Check-in Time: 22-Jun-2009 11:51:36 STScI Edit Number: 1 Title A Closeup View of a Twin of SN 1987A Before Explosion ------------------------------------------------------------------------------------ Type Cycle GO 17 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Nathan Smith University of California - Berkeley CoI: Prof. John Bally University of Colorado at Boulder N CoI: Mr. Adam Ginsburg University of Colorado at Boulder N CoI: Prof. Alex Filippenko University of California - Berkeley N ------------------------------------------------------------------------------------ Abstract Last year we reported the discovery of a ring nebula called SBW1 around a blue supergiant star in our Galaxy. In almost every respect, it is a true "twin" of the equatorial ring nebula around SN 1987A: it has an identical physical radius of 0.2pc, a similar expansion speed and age, it is located in a massive HII region, the central star is an early B supergiant with the same luminosity as SN1987A's progenitor, and the ring's structure in our ground-based H-alpha images looks almost identical to early HST images of SN1987A's ring. The detailed density structure of SN1987A's ring on scales smaller than the limiting resolution of HST has become a pressing question, because the forward shock of the supernova is now colliding with that ring, causing it to brighten by 3 orders of magnitude and giving rise to a series of "hotspots" around the ring. HST/WFC3 images of SBW1 will provide a snapshot of an SN1987A-like ring before the supernova explodes, and will provide a detailed view of the important density inhomogeneities in the ring with a physical spatial resolution 10 times better than HST images of SN1987A (because SBW1 is 10 times closer to us). STIS spectra will allow us to directly measure the radial density structure of the ring. Both the overall radial density profile and the detailed structures of the clumps that give rise to the "hotspots" are critical factors in modeling the rapid evolution of SN1987A, and our proposed study of SBW1 will provide extremely valuable input for those models. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program will obtain F656N, F658N, and F502N images with WFC3 of the ring nebula around SBW2, as well as STIS/CCD spectra including the H-alpha and [S II] emission lines. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments 11637( 3) - 22-Jun-2009 11:51:36 - [ 2] ------------------- ------------------------------------------------------------------------------------ 11637( 3) - 22-Jun-2009 11:51:36 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SBW1 STAR, B0-B2 III-I, BE, RA=10H40M19.4000S +/- 0.5", J2000 V = 12.7 CIRCUMSTELLAR MATTER, DEC=-59D49'9.70" +/- 0.5" EMISSION LINE NEBULA, RING Reference Frame: ICRS Comments: ------------------------------------------------------------------------------------------------------------------------------------ 11637( 3) - 22-Jun-2009 11:51:36 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 11637( 3) - 22-Jun-2009 11:51:36 - [ 5] Visit: 01 Visit Requirements: CVZ On Hold Comments: Additional Comments: for imaging, central star is centered on CCD1, and only CCD1 is read out. use 2-pt dither for all, and CR-SPLIT for F656N and F658N. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SBW1 WFC3/UVI ACCUM UVIS1-2K4 F502N CR-SPLIT=NO 1 210 S PATTERN 1 1-3 S -SUB Comments: not doing CR-SPLIT for the F502N images. ------------------------------------------------------------------------------------------------------------------------------------ 2 SBW1 WFC3/UVI ACCUM UVIS1-2K4 F658N CR-SPLIT=2 1 480 S S -SUB ------------------------------------------------------------------------------------------------------------------------------------ 3 SBW1 WFC3/UVI ACCUM UVIS1-2K4 F656N CR-SPLIT=2 1 420 S S -SUB ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SBW1 1 WFC3/UVI ACCUM UVIS1-2K F502N 1 none none none 1 N/A S 4-SUB SBW1 1 WFC3/UVI ACCUM UVIS1-2K F502N 2 none none none 1 N/A S 4-SUB SBW1 2 WFC3/UVI ACCUM UVIS1-2K F658N 1 none none 1 1 N/A S 4-SUB SBW1 2 WFC3/UVI ACCUM UVIS1-2K F658N 1 none none 2 1 N/A S 4-SUB SBW1 2 WFC3/UVI ACCUM UVIS1-2K F658N 2 none none 1 1 N/A S 4-SUB SBW1 2 WFC3/UVI ACCUM UVIS1-2K F658N 2 none none 2 1 N/A S 4-SUB SBW1 3 WFC3/UVI ACCUM UVIS1-2K F656N 1 none none 1 1 N/A S 4-SUB SBW1 3 WFC3/UVI ACCUM UVIS1-2K F656N 1 none none 2 1 N/A S 4-SUB SBW1 3 WFC3/UVI ACCUM UVIS1-2K F656N 2 none none 1 1 N/A S 4-SUB SBW1 3 WFC3/UVI ACCUM UVIS1-2K F656N 2 none none 2 1 N/A S 4-SUB 11637( 3) - 22-Jun-2009 11:51:36 - [ 6] Visit: 02 Visit Requirements: CVZ; ORIENT 72.0D TO 82.0 D; ORIENT 252.0D TO 262.0 D On Hold Comments: Additional Comments: The slit will be offset by 0.3 arcsec on either side of the star, and the slit should be oriented at a position angle of +32d (or +122d) with a tolernce of +-5d. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SBW1 STIS/CCD ACQ F28X50LP MIRROR 1 2 S ------------------------------------------------------------------------------------------------------------------------------------ 2 SBW1 STIS/CCD ACCUM 52X0.2 G750M 6581 CR-SPLIT=3 1 2070 S POS TARG -0.3, 0.0 Comments: slit offset perp-to-slit, placing slit 0.3 arcsec off of star's position to avoid saturation of bright central star in long exposures. ------------------------------------------------------------------------------------------------------------------------------------ 3 SBW1 STIS/CCD ACCUM 52X0.2 G750M 6581 CR-SPLIT=3 1 2070 S POS TARG 0.3, 0.0 Comments: spatial offset placing slit 0.3 arcsec on other side of star. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ SBW1 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A SBW1 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 1 1 N/A SBW1 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 2 1 N/A SBW1 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 3 1 N/A SBW1 3 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 1 1 N/A SBW1 3 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 2 1 N/A SBW1 3 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 3 1 N/A 11637( 3) - 22-Jun-2009 11:51:36 - [ 7] Summary Form for Proposal 11637 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP, UVIS1-2K4-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2, CR-SPLIT=3, CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ, ORIENT 252.0D TO 262.0 D, ORIENT 72.0D TO 82.0 D, PATTERN 1 1-3, POS TARG -0.3, 0.0, POS TARG 0.3, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N, F656N, F658N, G750M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names SBW1 ------------------------------------------------------------------------------------------------------------------------------------