Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 4824o Report Date: 09-May-96:20:33 Version: ********** Check-in Date: ********** 1.Proposal Title: A SEARCH FOR INTERSTELLAR GASEOUS LEAD ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID INTERSTELLAR MEDIUM GO Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Prof. L. M. Hobbs CHICAGO, UNIVERSITY OF USA (414) 245-5555 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract WE PROPOSE TO USE THIS DIRECTOR'S DISCRETIONARY TIME TO SEARCH FOR INTERSTELLAR ABSORPTION BY GASEOUS INTERSTELLAR LEAD IN THE SPECTRUM OF 1 SCO. IN OUR CYCLE 1 DATA FROM PROGRAM 3993, WE HAVE ALREADY SIMILARLY DETECTED INTER- STELLAR TIN TOWARD THE SAME STAR. AT Z=50, TIN IS BY FAR THE HEAVIEST ELEMENT YET DETECTED IN THE INTERSTELLAR MEDIUM, AND, AT Z=82, LEAD IS STILL MUCH HEAVIER. ON QUITE FIRM GROUNDS, WE EXPECT THE 1433 A LINE OF PB II TO ATTAIN A A STRENGTH OF ABOUT 3 MA TOWARD 1 SCO, OR ABOUT 40 % OF THAT OF THE SN II 1400 A LINE WHICH WE HAVE PREVIOUSLY DETECTED. SUCH A PB II LINE SHOULD BE READILY DETECTED IN THE SINGLE SPECTRAL EXPOSURE WHICH CONSTITUTES THIS PROGRAM. ------------------------------------------------------------------------------------ 8. Scientific Key Words: INTERSTELLAR CLOUDS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.37 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 4824o PI: Prof. L. M. Hobbs Proposal Title: A SEARCH FOR INTERSTELLAR GASEOUS LEAD ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ P.I. L. M. Hobbs CHICAGO, UNIVERSITY OF USA Dr. D. C. Morton HERZBERG INSTITUTE OF CANADA ASTROPHYSICS Dr. L. Spitzer Jr. PRINCETON UNIVERSITY USA Dr. D. E. Welty CHICAGO, UNIVERSITY OF USA Dr. D. G. York CHICAGO, UNIVERSITY OF USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. FOR ONE STAR, ONE GHRS EXPOSURE IS TO BE OBTAINED THROUGH THE SMALL SCIENCE APERTURE IN THE ACCUMULATION MODE, WITH THE 160M GRATING. THE EXPOSURE IS CENTERED AT 1425 A, BUT THE PB II LINE AT 1433 A IS OF PRIMARY IMPORTANCE. THE FP -SPLIT OPTION IS ADOPTED, TO ENHANCE THE LIKELIHOOD OF DETECTING A WEAK LINE. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. THE PROPOSED SCIENTIFIC PROGRAM CANNOT BE CARRIED OUT WITH ANY OTHER EXISTING TELESCOPE AND SPECTROGRAPH. THE HIGHEST POSSIBLE SPECTRAL RESOLVING POWER AND S/N RATIO ARE REQUIRED TO ACHIEVE A DETECTION OF THE EXPECTED VERY WEAK, NARROW LINE. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. THE EXPOSURE TIME REQURIED FOR THE ONE GHRS EXPOSURE IS GIVEN BELOW IN THE EXPOSURE LOGSHEET. OBSERVED, ABSOLUTE FLUXES MEASURED AT 1400 AND 1450 ANGSTROMS HAVE BEEN PUBLISHED FOR 1 SCO IN THE UV BRIGHT-STAR SPECTROPHOTOMETRIC CATALOGUE OF CATALOGUE OF JAMAR ET AL (1976). THE ABSOLUTE SENSITIVITY OF THE GHRS IS GIVEN IN THE GHRS INSTRUMENT HANDBOOK. THIS COMBINATION ALLOWS STRAIGHTFORWARD ESTIMATES OF THE REQUIRED EXPOSURE TIME. IN ADDITION, WE HAVE RECEIVED OUR CYCLE 1 DATA (PROGRAM ID=3993) FOR VERY SIMILAR EXPOSURES OF THE OF THE SAME STARS AT ADJACENT WAVELENGTHS, WHICH CONFIRM THE CALCULATED EXPOSURE TIMES DIRECTLY. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. WE WILL USE THE CALIBRATED SCIENCE DATA WHICH ARE PROVIDED AS THE OUTPUT OF THE ROUTINE SCIENCE DATA PROCESSING AND THE CALIBRATION DATA BASE SOFTWARE, AT THE ST ScI. SINCE WE WILL ANALYZE IN DETAIL ONLY ABSORPTION LINE PROFILES, WE DO NOT REQUIRE PRECISE INFORMATION ABOUT THE ABSOLUTE FLUXES. THE REDUCTIONS WILL BE CARRIED OUT USING IRAF/STSDAS, PRIMARILY. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). EXTENSIVE DATA-ANALYSIS CAPABILITIES WHICH ARE TAILORED PRECISELY FOR THIS KIND OF OBSERVATIONAL DATA AND ITS INTERPRETATION EXIST AT, AND WILL BE MADE AVAILABLE BY, OUR HOME INSTITUTIONS. ------------------------------------------------------------------------------------ 11. Address Information Name: L. M. HOBBS Category: PI Institution: UNIVERSITY OF CHICAGO Address: YERKES OBSERVATORY City: WILLIAMS BAY State: WI Zip Code: 531910258 Country: USA Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 4824o [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 14 HD141637 1 A,110 RA= 15H 47M 57.94S +/- 1950 V= +03 1 V=4.68+/-0.02, TYPE=B2.5V, E(B- SCO 0.01S, 2 V)=0.16 DEC= -25D 36' 03.0" +/- 0.1" 3 F-CONT(1480)=7.27 E-10 4 F-CONT(1600)=5.65 E-10 5 F-CONT(2000)=2.96 E-10 F-CONT(2400)=2.17 E-10 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 1950.00 -0.0200 +/- 0.0000 -0.0270 +/- 0.0000 0.0050 +/- 0.0050 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 4824o [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 306 DEFINE # HRS ACCUM 0.25 G160M 1425.0 FP-SPLIT=DSFOUR 1 9.6M # 3 # 162 STEP-PATT=5 Comments: GA II, PB II; 1.2MX2(SAMPL)X4(S /N=200) ------------------------------------------------------------------------------------------------------------------------------------ 714.1 HD141637 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE=5 1 5S 95 3 1 ONBOARD ACQ FOR BRIGHT=RETURN 714.2 LOCATE=YES SEQ 714.1-714.4 NO GAP CYCLE 2 / 714.1- 714.4 Comments: STEP-TIME = 0.2 SEC ------------------------------------------------------------------------------------------------------------------------------------ 714.2 HD141637 HRS ACQ/ 2.0 MIRROR-A2 1 9.2S 3 1 ONBOARD ACQ FOR PEAKUP 714.3-714.4 Comments: STEP-TIME = 0.2 SEC ------------------------------------------------------------------------------------------------------------------------------------ 714.3 HD141637 HRS IMAGE 2.0 MIRROR-A2 1 96.8S 3 1 Comments: STEP-TIME = 0.2 SEC; TAKE MAP AFTER CENTERING ------------------------------------------------------------------------------------------------------------------------------------ 714.4 USE 162 HD141637 X1.59 200 1 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 4824o [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ACQ ACQ/PEAKUP IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=DSFOUR STEP-PATT=5 SEARCH-SIZE=5 BRIGHT=RETURN LOCATE=YES ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.37 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MEDIUM ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 714.2; SEQ 714.1-714.4 NO GAP; CYCLE 2 / 714.1-714.4 ONBOARD ACQ FOR 714.3-714.4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M MIRROR-A2 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD141637 1 SCO ------------------------------------------------------------------------------------------------------------------------------------