7373( 4) - 01/21/99 11:49 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7373 Version: 4 Check-in Date: 21-Jan-1999 11:48:50 1.Proposal Title: Sher 25 in NGC 3603: A Galactic counterpart of SN 1987 A's progenitor ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Eva Grebel UCO/Lick Observatory CoI: Wolfgang Brandner University of Illinois at Urbana-Champaign N CoI: You-Hua Chu University of Illinois at Urbana-Champaign N CoI: Sean D. Points University of Illinois at Urbana-Champaign N CoI: Horacio Dottori Instituto di Fisica, UFRGS, Porto Alegre N ------------------------------------------------------------------------------------ 5. Abstract The B1.5 supergiant Sher 25 in the Galactic giant H II region NGC 3603 shows a circumstellar ring and bipolar outflow filaments similar to the ring structures detected around SN 1987 A. The star itself resembles Sk-69 202, the progenitor of SN 1987 A. Our ground-based optical observations revealed a complex circumstellar environment with a clumpy ring and a bipolar nebula around Sher 25. This ring is similar to that around SN 1987 A in both size and morphology. Follow-up high- resolution spectroscopy showed a high N II/H-alpha ratio, indicating a nitrogen enrichment in the nebula around Sher 25. Sher 25 must be a post-red supergiant and hence at similar evolutionary stage as Sk-69 202 was. We request Planetary Camera images of Sher 25's circumstellar nebula in the H-alpha and N II lines. These images allow us to study a Galactic counterpart of SN 1987 A's ring with a resolution of 0.003 pc. The detailed structure of Sher 25's circumstellar nebula will be compared to wind-interaction models in order to determine its mass loss history and the dominant type of instability responsible for the fragmentation of the ring. ------------------------------------------------------------------------------------ 7373( 4) - 01/21/99 11:49 - [ 2] Observations Description ------------------------ We will take Planetary Camera images of Sher 25 in the F656N and F658N filters. The surface brightness of the nebula is 1.3times10e-14 erg/sec/cm2/arcsec2 in the H-alpha line and 1.7times10e-14 erg/s/cm2/arcsec2 in the N II 6583 line. For an exposure time of 1000 sec to 1200 sec with CR-SPLIT, the expected S/N ratio is approximately 5 per pixel. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7373( 4) - 01/21/99 11:49 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SHER-25 STAR, B0-B2 III-I RA=11H 15M 7.76S +/- 0.3", DEC=- J2000 V = 12.3 61D 15' 12.5" +/- 0.3", PLATE- B-V = 1.4 ID=0610 Comments: PC1 center offset by 5"N from Sher-25 7373( 4) - 01/21/99 11:49 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENTation 270D TO 50D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SHER-25 WFPC2 IMAGE PC1-FIX F658N 1 1200 S ------------------------------------------------------------------------------------------------------------------------------------ 2 SHER-25 WFPC2 IMAGE PC1-FIX F656N 1 1000 S ------------------------------------------------------------------------------------------------------------------------------------ 7373( 4) - 01/21/99 11:49 - [ 5] Summary Form for Proposal 7373 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENTation 270D TO 50D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F658N F656N ------------------------------------------------------------------------------------------------------------------------------------ Target Names SHER-25 ------------------------------------------------------------------------------------------------------------------------------------