Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5462 Report Date: 18-Jul-95:17:27 Version: ********** Check-in Date: ********** 1.Proposal Title: THE ORIGIN OF C2 IN COMETS CYCLE4MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GO Target of Oppt. Sub Category COMETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Michael F A'hearn 2620 USA (301) 405 6076 ------------------------------------------------------------------------------------ 7. Abstract We propose to observe any comet which satisfies the constraint Q(C2) > 1.4E26 at r=1AU (scaled appropriately to other r) to map the Mulliken and Swan bands of C2. The relative intensities of the singlets and triplets and the excitation temperatures will be mapped as a function of distance from the nucleus. This will constrain the presently unknown formation mechanism for producing C2 and thus constrain the identity of its parent. It will also constrain the rate for intercombination (singlet-triplet) radiative transitions, thus providing crucial information required for the detailed study of the resonance fluorescence of C2. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 7.50 par: 0 10. Num targs pri: 5 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS WF/PC ------------------------------------------------------------------------------------ 12. Special sched req: Real Time obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5462 PI: Michael F A'hearn Proposal Title: THE ORIGIN OF C2 IN COMETS CYCLE4MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Michael F A'Hearn 2620 USA Claude Arpigny 4330 BELGIUM X Paul D Feldman 2380 USA William M Jackson 1510 USA Harold A Weaver 3470 USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We will observe a target-of-opportunity comet so the ephemeris will not be well known. We will therefore require WFPC-assisted, interactive acquisition with the first exposure putting the comet on WF3, located halfway from the center of the chip toward the apex of all four chips. We will then observe the comet with FOS at 5 radial positions. At each position we will take a short exposure with G570H to obtain the Swan bands of C2 (dv=+1 through dv=-2) and a long exposure with G270H to obtain the Mulliken bands (dv=0). The five positions should correspond to on-nucleus and offsets of 400, 800, 1600, and 3200 km (approximately). The spatial resolution, i.e. the choice of aperture, should be consistent with the spacing: 400km for the inner points, larger for the outer points. Use of on- board acquisition with FOS is desireable for the positions at and close to the nucleus but use of this technique is pending tests of whether the technique will work for a comet. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Only HST has the required spatial resolution and the capability of observing simultaneously (or nearly so) the Mulliken bands at 232nm and the Swan bands in the optical. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. This proposal requires a comet which is both sufficiently bright and sufficiently close to Earth. It is possible that comet Mueller will satisfy these requirements. It will satisfy the criterion for distance from Earth but the brightness is still very uncertain. We expect to notify STScI at least one month before the observations must be carried out. At that time, the ephemeris may not be sufficiently well known to achieve the sub-arcsecond pointing required for the exposures nearest the nucleus; we therefore require a WFPC-assisted, interactive acquisition and/or the capability of using on-board acquisition with FOS. The latter capability has never been tested on a comet and it is not yet known whether the spatial contrast is sufficient for the technique to work. We therefore presume use of WFPC-assist. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. DD observations of comet Levy (GO/DD 3064) have resulted in a published paper by Weaver et al. (1992) Icarus 97, 85-98. Images show that the temporal fluctuations in brightness are caused by quite different physical processes than were operative in P/Halley. GO observations of comet P/Hartley 2(GO 2481) have resulted in a paper which is now in press in ApJ by Weaver et al. These observations yielded the first detection of the Cameron bands of CO which we have interpreted as due to prompt emission following dissociation of CO2 into the upper state of the Cameron bands. Observations of comet Shoemaker-Levy 1991a1 (GO 2442 and GO 2483) are still being processed. Observations of comet P/Schaumasse (GO 3707) are still being processed. Images and spectra of comet Shoemaker-Levy 9 (GO/DD proposal) were taken in July 1993 and have been used to constrain the nuclear sizes and the outgassing rate. An abstract has been submitted to DPS and a very rough draft of a paper has been prepared. Observations of Ceres (GO 4545) were obtained in September 1993. These data at first glance appear to set a very interesting upper limit on any outgassing from Ceres but the data are still being processed. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). All hardware for the analysis of the observations and for the laboratory work is being provided at no cost by the institutions. Salary for the time of the PIs and of the coIs is being provided at no cost by the institutions. ------------------------------------------------------------------------------------ 11. Address Information Name: Michael F A'Hearn Category: PI Institution: 2620 Address: Department of Astronomy University of Maryland City: College Park State: MD Zip Code: 207422421 Country: USA Telephone: (301) 405 6076 Telex (or e-mail): ma@astro.umd.edu ------------------------------------------------------------------------------------ Name: Category: CON Institution: Address: City: State: Zip Code: Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5462 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: MUELLER ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET MUELLER (1993P), TARG. OF OPP. TENTATIVE CHOICE, CENTERED ON NUCLEUS ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET, | Q=0.9668992, E=1.0, | I=105.01213, O=193.79440, | W=261.05554, | T=26-MAR-1994:06:20:42, | EQUINOX=J2000, | EPOCH=01-SEP-93:00:00:00, ACQ=0.25 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 12. | OPTIMUM OBSERVING TIME IS 1994 APRIL 2 |SURF-LINE(5165) = 4. E-13 | 25 TO 1994 MAY 5 (MINIMUM GEOCENTRIC 3 |W-LINE(5165) = 40. | DISTANCE, WEIGHTED TOWARD SMALLER 4 |SURF-LINE(2320) = 3. E-15 | HELIOCENTRIC DISTANCE) 5 |W-LINE(2320) = 10. | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: MUELLER-OFF-1 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET MUELLER, 400 KM SUNWARD ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET, | TYPE = POS_ANGLE, Q=0.9668992, E=1.0, | RAD = 1.0, I=105.01213, O=193.79440, | ANG = 0.0, W=261.05554, | REF = SUN, T=26-MAR-1994:06:20:42, | EQUINOX=J2000, | EPOCH=01-SEP-93:00:00:00 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 12. | DESIRED OFFSET APPROX 400 KM TOWARD 2 |SURF-LINE(5165) = 4. E-13 | SUN. ANGULAR OFFSET DEPENDS ON 3 |W-LINE(5165) = 40. | GEOCENTIRC DISTANCE OF COMET. 4 |SURF-LINE(2320) = 3. E-15 | 5 |W-LINE(2320) = 10. | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5462 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: MUELLER-OFF-2 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET MUELLER 800 KM SUNWARD ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET, | TYPE = POS_ANGLE, Q=0.9668992, E=1.0, | RAD = 2.0, I=105.01213, O=193.79440, | ANG = 0.0, W=261.05554, | REF = SUN, T=26-MAR-1994:06:20:42, | EQUINOX=J2000, | EPOCH=01-SEP-93:00:00:00 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 12. | DESIRED OFFSET APPROX 800 KM TOWARD 2 |SURF-LINE(5165) = 4. E-13 | SUN. ANGULAR OFFSET DEPENDS ON 3 |W-LINE(5165) = 40. | GEOCENTRIC DISTANCE OF COMET. 4 |SURF-LINE(2320) = 3. E-15 | 5 |W-LINE(2320) = 10. | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 4 | TARGET NAME: MUELLER-OFF-3 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET MUELLER 1600 KM SUNWARD ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET, | TYPE = POS_ANGLE, Q=0.9668992, E=1.0, | RAD = 4.0, I=105.01213, O=193.79440, | ANG = 0.0, W=261.05554, | REF = SUN, T=26-MAR-1994:06:20:42, | EQUINOX=J2000, | EPOCH=01-SEP-93:00:00:00 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 12. | DESIRED OFFSET APPROX 1600 KM TOWARD 2 |SURF-LINE(5165) = 2.5E-13 | SUN. ANGULAR OFFSET DEPENDS ON 3 |W-LINE(5165) = 40. | GEOCENTRIC DISTANCE OF COMET. 4 |SURF-LINE(2320) = 2. E-15 | 5 |W-LINE(2320) = 10. | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5462 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 5 | TARGET NAME: MUELLER-OFF-4 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET MUELLER 3200 KM SUNWARD ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | TYPE=COMET, | TYPE = POS_ANGLE, Q=0.9668992, E=1.0, | RAD = 8.0, I=105.01213, O=193.79440, | ANG = 0.0, W=261.05554, | REF = SUN, T=26-MAR-1994:06:20:42, | EQUINOX=J2000, | EPOCH=01-SEP-93:00:00:00 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |SURF(V) = 12. | DESIRED OFFSET APPROX 3200 KM TOWARD 2 |SURF-LINE(5165) = 1.5E-13 | SUN. ANGULAR OFFSET DEPENDS ON 3 |W-LINE(5165) = 40. | GEOCENTRIC DISTANCE OF COMET. 4 |SURF-LINE(2320) = 1. E-15 | 5 |W-LINE(2320) = 10. | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5462 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 DEFINE # FOS/RD ACQ 4.3 MIRROR 1 60 S 30 1 2 CYCLE 4 VERIFY Comments: PSEUDO-IMAGE USED TO VERIFY POINTING ------------------------------------------------------------------------------------------------------------------------------------ 2 DEFINE MUELLER FOS/RD ACQ/ 1.0 MIRROR 1 1 S 15 1 1 CYCLE 4 REDACQ BINARY Comments: THIS ACQUISITION IS USED ONLY FOR THE NUCLEAR POINTING. OTHER POINTINGS ASSUMED CARRIED BY GUIDE-STAR HANDOFF. ------------------------------------------------------------------------------------------------------------------------------------ 3 DEFINE # FOS/RD ACCUM # G570H 4600- 1 2 M 30 2 1 CYCLE 4 SWAN 6500 3 Comments: SHORT EXPOSURE FOR SWAN BANDS. ------------------------------------------------------------------------------------------------------------------------------------ 4 DEFINE # FOS/RD ACCUM # G270H 2230- 1 24 M 10 4 1 CYCLE 4 MULLIKE 2600 5 N Comments: LONG EXPOSURE FOR MULLIKEN BANDS. ------------------------------------------------------------------------------------------------------------------------------------ 5 DEFINE MUELLER WFPC2 IMAGE WF3 F702W 7020 1 700 S 100 1 1 CYCLE 4 IMAGE POS TARG +20, +20 ------------------------------------------------------------------------------------------------------------------------------------ 5.9 USE MUELLER VERIFY Comments: DUMMY EXPOSURE TO FORCE CORRECT OBSET STRUCTURE. SPSS SHOULD DUMMY THIS LINE. ------------------------------------------------------------------------------------------------------------------------------------ 6 USE SEQ 5.9-19 NO GAP IMAGE INT ACQ FOR 7 Comments: WF ACQ IMAGE FOR 7-21 FGS CONTROL FOR 7-12 FGS CONTROL PREFERRED FOR ALL, USE GYROS IF FGS NOT AVAIL. FOR 13-19. SCIENCE OPTIMIZED IF THIS PROGRAM EXECUTED ADJACENT TO PROGRAM Z540. ------------------------------------------------------------------------------------------------------------------------------------ 7 USE MUELLER GUIDE TOL 0.2" / VERIFY 5.9-21 SEQ 7-9 NO GAP Comments: IF ONBOARD ACQ IS FEASIBLE ON COMET, WE WILL USE REDACQ INSTEAD. INTEND 7-9 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5462 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 8 USE MUELLER 1.0 SWAN Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. ------------------------------------------------------------------------------------------------------------------------------------ 9 USE MUELLER 1.0 MULLIKE N Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. ------------------------------------------------------------------------------------------------------------------------------------ 10 USE MUELLER-OFF SEQ 10-12 NO GAP VERIFY -1 Comments: INTEND 10-12 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ 11 USE MUELLER-OFF 1.0 SWAN -1 Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. ------------------------------------------------------------------------------------------------------------------------------------ 12 USE MUELLER-OFF 1.0 MULLIKE -1 N Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. ------------------------------------------------------------------------------------------------------------------------------------ 13 USE MUELLER-OFF SEQ 13-15 NO GAP VERIFY -2 Comments: INTEND 13-15 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ 14 USE MUELLER-OFF 1.0 SWAN -2 Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. ------------------------------------------------------------------------------------------------------------------------------------ 15 USE MUELLER-OFF 1.0 MULLIKE -2 N Comments: APERTURE MAY BE 0.5, DEPENDING ON DISTANCE OF COMET. CONTINUE ON GYROS IF GUIDE STARS LOST. ------------------------------------------------------------------------------------------------------------------------------------ 16 USE MUELLER-OFF 1.0 X1.25 SWAN -3 Comments: APERTURE MAY CHANGE, DEPENDING ON DISTANCE OF COMET. INTEND 16 -17 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5462 [ 9] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 17 USE MUELLER-OFF 1.0 X1.25 MULLIKE -3 N Comments: APERTURE MAY CHANGE, DEPENDING ON DISTANCE OF COMET. CONTINUE ON GYROS IF GUIDE STARS LOST. ------------------------------------------------------------------------------------------------------------------------------------ 18 USE MUELLER-OFF 1.0 X1.25 SWAN -4 Comments: APERTURE MAY BE 4.3, DEPENDING ON DISTANCE OF COMET. INTEND 18 -19 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ 19 USE MUELLER-OFF 1.0 X1.25 MULLIKE -4 N Comments: APERTURE MAY BE 4.3, DEPENDING ON DISTANCE OF COMET. CONTINUE ON GYROS IF GUIDE STARS LOST. ------------------------------------------------------------------------------------------------------------------------------------ 20 USE MUELLER-OFF 1.0 X1.25 SWAN -4 Comments: APERTURE MAY BE 4.3, DEPENDING ON DISTANCE OF COMET. INTEND 20 -21 TO FILL ONE ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ 21 USE MUELLER-OFF 1.0 X1.25 MULLIKE -4 N Comments: APERTURE MAY BE 4.3, DEPENDING ON DISTANCE OF COMET. CONTINUE ON GYROS IF GUIDE STARS LOST. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5462 [ 10] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/RD WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/BINARY ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 7.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category COMETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4; POS TARG +20, +20; SEQ 5.9-19 NO GAP; INT ACQ FOR 7; GUIDE TOL 0.2" / 5.9-21; SEQ 7-9 NO GAP; SEQ 10-12 NO GAP; SEQ 13-15 NO GAP; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G570H G270H F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names MUELLER MUELLER-OFF-1 MUELLER-OFF-2 MUELLER-OFF-3 MUELLER-OFF-4 ------------------------------------------------------------------------------------------------------------------------------------