7509( 4) - 06/17/97 13:25 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7509 Version: 4 Check-in Date: 17-Jun-1997 13:25:15 1.Proposal Title: High-Velocity Gas and Dust Evolution in Chamaeleon Clouds ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle INTERSTELLAR MATTER GO 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: FRANCOIS BOULANGER INSTITUT D'ASTROPHYSIQUE SPATIALE CoI: Edith Falgarone Ecole Normale Superieure N CoI: Cecile Gry Laboratoire d'Astronomie Spatiale Y CoI: James Lequeux Observatoire de Paris N CoI: Guillaume Pineau des For\^ets Observatoire de Meudon N ------------------------------------------------------------------------------------ 6. Abstract GHRS absorption spectra obtained for a nearby star located behind the complex of molecular clouds in Chamaeleon show that 10\ cm^-2) is at large velocities (up to - 50 km/s) compared to the main absorption component near v_lsr = 0 km/s. From the excitation of SiII and CII, we infer physical conditions ( n_e ~ 10 cm^-3 , T $~ 1000K) which are unusual in a region where there is no ionizing star. The cooling rate in the 35Mum fine structure line of Si^+ alone is a factor 20 larger than the average cooling rate of the gas in the Solar Neighborhood. A large amount of kinetic energy is thus being deposited in this gas, possibly by a shock driven by infalling gas impacting onto the gas at 0 km/s. The line of sight was selected on the basis of IRAS data showing that the absorbing cloud has an exceptionally large abundance of small grains. The HST data shows that in the high velocity gas all of the Silicon is in the gas phase which suggests significant dust destruction. We propose to get high resolution absorption spectra for this unique sight-line to measure the abundance and excitation of Si, Fe, O, C and Mg. These measurements will be used to study physical conditions, gas energetics and dust destruction as a function of velocity. They should provide keys to the processes that heat the gas and disrupt dust grains and to the possible links between these processes. ------------------------------------------------------------------------------------ 7509( 4) - 06/17/97 13:25 - [ 2] Observations Description ------------------------ The observations will use STIS with two different echelle modes : E140H at 1293 Angstrom and E230H at 2719 Angstrom which will give complete coverage from 1188 Angstrom to 1398 Angstrom and from 2585 Angstrom to 2852 Angstrom at a resolving power in excess of 100,000. The exposure times (160 min for the E140H exposure and 30 min for the E230H exposure) have been computed with the STIS Exposure Time Calculator in order to get with the 0.2*0.09 arcsec and 0.1*0.09 arcsec slits a S/N of 30 at the bottom of the stellar SiII* and FeII absorption lines where the interstellar absorption occurs. The flux of the star is taken from the medium resolution spectra previously obtained with GHRS and IUE., The visibility time is 59 min per orbit for our target, the total acquisition time (guide star, target and peakup) for the first orbit is 37 min and the re- acquisition time in the subsequent orbits is 6 min. The instrument overhead for each exposure is 8 min. Consequently there are 14 min available for the science exposure in the first orbit, and 53 min in the subsequent orbits. A total of 4 orbits is thus needed for the first exposure with E140H and 1 more orbit for the E230H exposure. These two exposures will give access in particular to the following atomic lines : NI 1200 (triplet), SIII 1190.208, SII 1250.584, SII 1253.811, SII 1259.519, SiII 1190.416, SiII 1193.290, SiII 1260.422, SiII* 1264.738, SiII* 1265.002, SiII 1304.370, SiIII 1206.500, HI 1215.67, CI, CI*, CI** (several multiplets with 2 orders of magnitude in the f-values), OI 1302.168, OI* 1304.858, OI** 1306.029, CII 1334.532, CII* 1335.663, CII* 1335.708, NV 1238.821, NV 1242.804, SiIV 1393.755, FeII 1260.533, FeII 2374.461, FeII 2382.765, FeII* 2383.788, FeII 2586.65, FeII 2600.173, MgII 2795.528, MgII 2803.531. Real Time Justification ----------------------- For the OI lines, we expect a telluric absorption line, therefore we request the observation to be achieved when the projected Earth velocity with respect to the LSR is positive. We have two ISO proposals related to this research project. A first proposal has been accepted to observe the IR fine structure lines in emission (C^+, Si^+, O), as well as the H_2 lines, expected to be the most efficient coolants of warm gas. In a second proposal we have obtained observing time to map the near and mid-IR emission from small grains, with the ISO camera at 6" angular resolution, around all lines of sight for which we have measured the UV extinction curve. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 7509( 4) - 06/17/97 13:25 - [ 3] Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7509( 4) - 06/17/97 13:25 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD102065 STAR, B6-B9.5 V-IV RA= 11H 43M 37.87S +/-0.04S, J2000 V = 6.7 DEC=-80D 28' 59.4" +/-0.67" TYPE=B9IV B-V = 0.2 F-CONT(1250)=8+/-0.5e-12 F-CONT(1450)=1.8+/-0.2e-11 F-CONT(1900)=1.0+/-0.5e-11 F-CONT(2300)=5+/-1e-12 F-CONT(2800)=8+/-1e-12 Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1950 -.026 .003 0.0 7509( 4) - 06/17/97 13:25 - [ 5] Visit: 01 Visit Requirements: BETWEEN 21-DEC-97 AND 01-APR-98 On Hold Comments: Additional Comments: The dates for the BETWEEN requirement are to be updated. To avoid that the OI telluric line falls in the IS profile. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 HD102065 STIS/C ACQ F25ND3 MIRROR 1 0.1 S ONBOARD ACQ FOR 12 CD ------------------------------------------------------------------------------------------------------------------------------------ 12 HD102065 STIS/C ACQ/PEA 0.1X0.0 G430L 4300 1 0.2 S ONBOARD ACQ FOR 13-17 CD K 9 ------------------------------------------------------------------------------------------------------------------------------------ 13 HD102065 STIS/F ACCUM 0.2X0.0 E140H 1234 5 24 M UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 14 HD102065 STIS/F ACCUM 0.2X0.0 E140H 1416 1 20 M UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 15 HD102065 STIS/F ACCUM 0.2X0.0 E140H 1598 1 24 M UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 16 HD102065 STIS/N ACCUM 0.1X0.0 E230H 2513 1 18 M UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 17 HD102065 STIS/N ACCUM 0.1X0.0 E230H 2762 1 18 M UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 7509( 4) - 06/17/97 13:25 - [ 6] Summary Form for Proposal 7509 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category INTERSTELLAR MATTER ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 21-DEC-97 AND 01-APR-98 ONBOARD ACQ FOR 12 ONBOARD ACQ FOR 13-17 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430L E140H E230H ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD102065 ------------------------------------------------------------------------------------------------------------------------------------