7940( 4) - 05/07/98 08:58 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7940 Version: 4 Check-in Date: 07-May-1998 08:57:34 1.Proposal Title: Dust Formation in the Wolf-Rayet Star WR137: NICMOS Follow-up ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/DD 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: ANTHONY F.J. MOFFAT UNIVERSITY OF MONTREAL CoI: Sergey Marchenko Universite de Montreal Y CoI: Yves Grosdidier Universite de Montreal N ------------------------------------------------------------------------------------ 5. Abstract We propose to use NICMOS on HST to take a second image of the dust formation region in the 13-year elliptical-orbit wind-interacting binary WR 137 = HD 192641 (WC7+OB), within a few months after periastron passage, which occured around July-September 1997. Ground-based IR photometry shows that copious amounts of carbon- rich dust are forming around current periastron passage, when wind- wind collision compression is at its peak. Recently we obtained (GO # 7369, September 1997) direct images of HD 192641 with NIC-2 through the F165M, F237M filters. We have resolved, for the first time, IR-emitting dust in the close environment of HD 192641. As expected on the basis of groundbased, spatially unresolved IR spectrosocopy, we saw the dust emission only in the K-band, not in the H-band. We found that the dust emission occured in a few strong clumps within about 0.5" from the star. In order to study the dynamics of the dust formation, we request a follow-up NICMOS orbit. ------------------------------------------------------------------------------------ 7940( 4) - 05/07/98 08:58 - [ 2] Observations Description ------------------------ VISIT 1, EXPOSURES 1 and 2: 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, with very short exposure times, 0.203-0.406 s, to avoid saturation. Based on the previous images (GO # 7369), 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 exactly the same modes for F165M and F237M. SPIRAL-DITH: MULTIACCUM, SCAMRR, NSAMP=2 (i.e 2 times the shortest exposure, 0.203 sec), NUM -POS=6, PATTERN-ORIENT=DETECTOR, Number_of_iterations=4, DITH-SIZE=3". To be useful, the data should be obtained within ~a year of maximum dust emission, i.e. by September 1998 at the latest, but preferably as soon as possible. We expect that the distribution and emissivity of the shock- produced dust will vary on a relatively short, order of months, time-scale. The images taken at March-May 1998 will allow us to study the dynamics of the already detected dust clumps. VISIT 1, EXPOSURES 3 and 4: 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: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7940( 4) - 05/07/98 08:58 - [ 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 7940( 4) - 05/07/98 08:58 - [ 4] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 15-Feb-98 AND 30-Sep-98 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, 4 DEF CUM DITH-SIZE=3,SAMP-SEQ=SCAMRR, NSAMP=2,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 2 HD192641 NIC2 MULTIAC NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 4 DEF CUM DITH-SIZE=3,SAMP-SEQ=SCAMRR, NSAMP=2,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 3 HD193077 NIC2 MULTIAC NIC2 F237M PATTERN=SPIRAL-DITH,NUM-POS=6, 4 DEF CUM DITH-SIZE=3,SAMP-SEQ=SCAMRR, NSAMP=2,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 4 HD193077 NIC2 MULTIAC NIC2 F165M PATTERN=SPIRAL-DITH,NUM-POS=6, 4 DEF CUM DITH-SIZE=3,SAMP-SEQ=SCAMRR, NSAMP=2,PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ 7940( 4) - 05/07/98 08:58 - [ 5] Summary Form for Proposal 7940 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PATTERN=SPIRAL-DITH NUM-POS=6 DITH-SIZE=3 SAMP-SEQ=SCAMRR NSAMP=2 PATTERN-ORIENT=DETECTOR ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 15-Feb-98 AND 30-Sep-98 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F237M F165M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD192641 HD193077 ------------------------------------------------------------------------------------------------------------------------------------