7369( 4) - 04/08/97 09:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7369 Version: 4 Check-in Date: 08-Apr-1997 09:22:42 1.Proposal Title: Dust Formation in Hot Stellar Winds: Infra-Red Imaging of the Wolf-Rayet Binary WR137 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle HOT STARS AND STELLAR GO 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: ANTHONY F.J. MOFFAT UNIVERSITY OF MONTREAL CoI: Sergey Marchenko Universite de Montreal Y CoI: Yves Grosdidier Universite de Montreal N ------------------------------------------------------------------------------------ 6. Abstract We propose to use NICMOS on HST to image the dust formed in the bow shock region of the 12.6-year elliptical-orbit binary WR 137 = HD 192641 (WC7+OB), within a year after periastron passage, predicted to occur in late 1996 or early 1997. Ground - based IR photometry has shown that copious amounts of carbon- rich dust are formed just after periastron passage, when wind- wind collision compression is at its peak. WR 137 is the currently most favorable system for the direct detection of the extended dust formation region among all known WR episodic dust emitters. Imaging of the dust emitting region will directly test for the first time the concept of wind- wind collision and allow one to study how and where dust can form in such a hostile environment. ------------------------------------------------------------------------------------ 7369( 4) - 04/08/97 09:26 - [ 2] Observations Description ------------------------ VISIT 1: We propose to obtain images of the bright `dust-making' Wolf-Rayet star WR137 = HD192641 (K=6.6-6.2mag, H=6.8mag), in the medium-bands F165M and F237M, widely varying the exposure times, from the shortest possible 0.203 s to 19 sec per individual exposure. The former is reqired in order to remain a factor ~two below the saturation limit, and the latter enables us to explore the outer, fainter dust-forming regions, without causing gross saturation in the image center. We expect to see the dust cone in F237M only; the F165M data will serve to locate the exact position of the stellar source relative to field stars. The observations will be carried out in two slightly different modes, almost exactly the same (save the variable DITH-SIZE and PATTERN-ORIENT) for F165M and F237M. 1. SPIRAL-DITH: MULTIACCUM, SCAMRR, NSAMP=3 (i.e 3times the shortest exposure, 0.203 sec), NUM-POS=6, PATTERN-ORIENT=DETECTOR or 22.5, Number_of_iterations=3, DITH-SIZE=4 or 6". 2. SPIRAL-DITH, the same program for F165M and F237M : ACCUM, NUM-POS=6, PATTERN-ORIENT=45.0 or 67.5, Number_of_iterations=3, DITH-SIZE=4 or 6", exposure time 19.65 sec. To be useful, the data should be obtained within ~a year of maximum dust emission, i.e. by the beginning of 1998 at the latest. VISIT 2: We will also obtain identical images with absolutely identical parameters of a nearby WR star WR138=HD193077 (WN6+OB), with similar brightness (K=6.6mag) but without any expected extended dust emission, to calibrate precisely the PSF, thus allowing a more precise study of structure in the dust cone. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7369( 4) - 04/08/97 09:26 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD192641 STAR RA=20H 14M 31.79S +/- 0.02S, J2000 F(2.37)=7.5+/-1.0e-14 DEC=36D 39' 39.1" +/- 0.7", PLATE-ID=004C Comments: The flux is variable, in erg/cm2/s/A, at 2.37 microns 2 HD193077 STAR RA=20H 17M 00.07S +/- 0.02S, J2000 F(2.37)=6.6e-14 DEC=37D 25' 23.0" +/- 0.7", PLATE-ID=004C Comments: The flux is in erg/cm2/s/A, at 2.37 microns 7369( 4) - 04/08/97 09:26 - [ 4] Visit: 01 Visit Requirements: BETWEEN 1-SEP-97 AND 31-DEC-97 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 HD192641 NIC2 MULTIAC NIC2 F237M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 DEF CUM DITH-SIZE=4,SAMP-SEQ=SCAMRR, NSAMP=3,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 2 HD192641 NIC2 MULTIAC NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 DEF CUM DITH-SIZE=6,SAMP-SEQ=SCAMRR, NSAMP=3,PATTERN-ORIENT=22.5 ------------------------------------------------------------------------------------------------------------------------------------ 3 HD192641 NIC2 ACCUM NIC2 F237M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 19.65 S DITH-SIZE=4,NREAD=1, PATTERN-ORIENT=45.0 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD192641 NIC2 ACCUM NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 19.65 S DITH-SIZE=6,NREAD=1, PATTERN-ORIENT=67.5 ------------------------------------------------------------------------------------------------------------------------------------ 7369( 4) - 04/08/97 09:26 - [ 5] Visit: 02 Visit Requirements: AFTER 1 BY 0H TO 2H 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 HD193077 NIC2 MULTIAC NIC2 F237M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 DEF CUM DITH-SIZE=4,SAMP-SEQ=SCAMRR, NSAMP=3,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 2 HD193077 NIC2 MULTIAC NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 DEF CUM DITH-SIZE=6,SAMP-SEQ=SCAMRR, NSAMP=3,PATTERN-ORIENT=22.5 ------------------------------------------------------------------------------------------------------------------------------------ 3 HD193077 NIC2 ACCUM NIC2 F237M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 19.65 S DITH-SIZE=4,NREAD=1, PATTERN-ORIENT=45.0 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD193077 NIC2 ACCUM NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 3 19.65 S DITH-SIZE=6,NREAD=1, PATTERN-ORIENT=67.5 ------------------------------------------------------------------------------------------------------------------------------------ 7369( 4) - 04/08/97 09:26 - [ 6] Summary Form for Proposal 7369 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PATTERN=SPIRAL-DITH NUM-POS=6 DITH-SIZE=4 SAMP-SEQ=SCAMRR NSAMP=3 PATTERN-ORIENT=DETECTOR PATTERN-ORIENT=22.5 PATTERN-ORIENT=45.0 PATTERN-ORIENT=67.5 DITH-SIZE=6 NREAD=1 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category HOT STARS AND STELLAR CORPSES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 1-SEP-97 AND 31-DEC-97 AFTER 1 BY 0H TO 2H ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F237M F165M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD192641 HD193077 ------------------------------------------------------------------------------------------------------------------------------------