Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5743 Report Date: 18-Jul-95:17:55 Version: ********** Check-in Date: ********** 1.Proposal Title: PLUTOS FUV SPECTRUM: CO ABUNDANCE AND FUV SURVEY carryover from 3803 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID SOLAR SYSTEM GO/CAR Sub Category MINOR PLANETS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Laurence M Trafton TEXAS, UNIVERSITY OF USA 512-471-1476 ------------------------------------------------------------------------------------ 7. Abstract We propose FUV observations of Pluto using the FOS/BL with G190H to survey the spectral region 2200-1800 A for absorption features, and the FOS/BL with G130H to survey the spectral region 1608-1200 A for emission features, or fluorescence, in Pluto's atmosphere. The spectral resolutions are delta lambda = 2.3 A and 1.6 A, respectively. A high priority will be to search for the cosmogonically important molecule CO using two vibrational Cameron bands in absorption at 2060 A and 1989 A, and the (1-0) and other 4th positive vibrational bands in emission near 1500 A, in order to determine an accurate CO column abundance and to constrain the rotational temperature of CO. Detection of both emission and absorption bands would set constraints on models of atmospheric escape by providing information on the radial distribution of CO in Pluto's lower atmosphere. We also search for other species, such as NO. Only HST has the sensitivity and spatial resolution to obtain Pluto's FUV spectrum. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 5.26 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5743 PI: Laurence M Trafton Proposal Title: PLUTOS FUV SPECTRUM: CO ABUNDANCE AND FUV SURVEY carryover from 3803 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Laurence M Trafton TEXAS, UNIVERSITY OF USA S. A. Stern SOUTHWEST RESEARCH INSTITUTE USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. Description of proposed observations: We plan to acquire Pluto when Charon is near elongation and Pluto is not far from opposition. For the 2200-1800A region only, a real-time peak up will center Pluto in the 1" aperture and exclude Charon, which will be about 0.9" away and about 5 times fainter. This aperture will minimize the contamination of Pluto's spectrum by Charon. A 3.2 hr exposure will be obtained with the FOS/RD+G190H+1.0" aperture. The 1608-1200A region will be observed with FOS/BL+G130H+1"aperture over an additional 4 hr total exposure. This will survey the FUV emission spectrum of Pluto and the 4th positive CO bands near 1500A. No attempt will be made to exclude Charon from this aperture since the continuum flux from both Pluto and Charon are both negligible at 1500A owing to the weak solar flux. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Justify the need for the capabilities of HST: Pluto's FUV spectrum has never been observed. Pluto is the only planet not visited by a spacecraft. IUE was able to observe Pluto's spectrum only down to 2500A before reaching its limit of sensitivity. Only HST has the sensitivity to observe Pluto's FUV spectrum. High spatial resolution is needed to separate Pluto's spectrum from Charon's. Only the UV offers molecular absorption coefficients large enough for detecting many trace constituents. Pluto's strong CH4 spectrum critically interferes with detecting CO in the infrared; only the UV allows a practicable way to measure Pluto's CO abundance. CO emission from Pluto's extended atmosphere can only be observed in the UV. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. Justify any special scheduling requests: The observations need to be scheduled when Charon is not far from elongation so that its continuum spectrum will not contaminate Pluto's for the longer wavelength observations using the FOS. Pluto would be available about 70% of the time. Schedule to minimize background Dark Count: Avoid the SSA and high magnetic latitudes. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. List any special calibration requirements for your observations ------------------------------------------------------------------------------------ 8. Additional comments or special requests. Additional comments or requests: None. Page 3 ------------------------------------------------------------------------------------ 9. Description of previous HST work. Description of any previous HST data: a. List HST program numbers and titles, and specify whether they are related to this project or not. Trafton: 1202 Lyman -alpha and H2 Survey; No 1203 Jovian Auroral Ly-alpha Profile; No 1204: Io Proton Aurora? No 1205: SO2 on Io; No 1206 Sulfur Near Io; No 2569: UV Rotational Light Curves for Pluto, and Charon's UV Spectrum; Yes 2957 High Resolution UV Spectropy of Triton,; No 2560: Integrated Dynamical and Spectroscopic Observations of Jupiter and Saturn; No Stern: 2957 High Resolution UV Spectropy of Triton,; No 2569: UV Rotational Light Curves for Pluto, and Charon's UV Spectrum; Yes b. Summarize the main results obtained from previous related programs. No results yet. c. List publications resulting from the above data (Format: Title, Authors,Journal, Volume, Page, and Year.) "First results from the GHRS: Resolved velocity and density structure in the beta pictoris circumstellar gas", A. Boggess, F. C. Bruhweiler, C. A. Grady, D. C. Ebbets, Y. Kondo, L. M. Trafton, J. C. Brandt, and S. R. Heap, Astrophys. J. (Letters), Aug 15 , 1991. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Resources to be supplied by your institution: Facilities of the UT Computation Center and Advanced Graphics Laboratory are available to support this project, as well as a Sun 4 Sparcstation. A pool of astronomy graduate students is also available from which to draw research assistants. Ground based observations of Io are periodically made from MacDonald Observatory for related studies. The Southwest Research Institute will support this project by providing all required computing facilities for the Co-I and visiting PI. ------------------------------------------------------------------------------------ 11. Address Information Name: LAURENCE M TRAFTON Category: PI Institution: UNIVERSITY OF TEXAS Address: ASTRONOMY DEPARTMENT UNIVERSITY OF TEXAS AT AUSTIN City: AUSTIN State: TX Zip Code: 78712 Country: USA Telephone: 512-471-1476 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST b)Solar System Targets ID = 5743 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: PLUTO-BL ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: PLANET PLUTO ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD = PLUTO, ACQ = 0.07 | | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | WND1 = 15-APR-94 TO 30-APR-95, | SEP OF PLUTO CHARON FROM EARTH | GT 0.75" WITHIN WND1 | ------------------------------------------------------------------------------------------------------------------------------------ REF | DATA | COMMENTS | | 1 |V = 13.9 +/- 0.5 | OBSERVE PLUTO WITH CHARON NOT FAR 2 |TYPE = G2V | FROM ELONGATION (OUT OF THE WAY). 3 |F-CONT(2400) = 1.5 +/- 1.0 E-16 | 4 |F-CONT(2000) = 1.8 +/- 0.5 E-17 | | ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5743 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 TALED FOS/BL ACQ 0.3 MIRROR 1 120.0S 1 1 RT ANALYSIS 2 SEQ 1-1.3 NON-INT CYCLE 4 / 1-2 GROUP 1-2 WITHIN 36H ------------------------------------------------------------------------------------------------------------------------------------ 1.2 PLUTO-BL FOS/BL ACQ 4.3 MIRROR 1 480S 1 1 INT ACQ FOR 2 2 Comments: MAKE A PICTURE. FOR REAL TIME CENTERING FIGURE DURING EARTH OCCULTATION ------------------------------------------------------------------------------------------------------------------------------------ 1.3 TALED FOS/BL ACQ 0.3 MIRROR 1 120S 1 1 RT ANALYSIS 2 Comments: LOCATE APERTURE. ------------------------------------------------------------------------------------------------------------------------------------ 2 PLUTO-BL FOS/BL ACCUM 1.0 G190H 1950 1 191M 12 4 1 Comments: EXPOSURE REDUCED FROM 239M TO ACCOUNT FOR COSTAR. ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5743 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 5.26 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category MINOR PLANETS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements RT ANALYSIS; SEQ 1-1.3 NON-INT; CYCLE 4 / 1-2; GROUP 1-2 WITHIN 36H; INT ACQ FOR 2 RT ANALYSIS ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G190H ------------------------------------------------------------------------------------------------------------------------------------ Target Names PLUTO-BL ------------------------------------------------------------------------------------------------------------------------------------