! $Id: 5389,v 4.1 1994/07/27 17:25:23 pepsa Exp $ coverpage: title_1: THE NATURE OF INTERSTELLAR CLOUD ENVELOPES -- PHYSICAL title_2: CONDITIONS AND STRUCTURE sci_cat: INTERSTELLAR MEDIUM sci_subcat: ABSORPTION LINES proposal_for: GO pi_fname: DAVID pi_mi: L. pi_lname: LAMBERT pi_inst: UNIVERSITY OF TEXAS pi_country: USA pi_phone: 512-471-7438 hours_pri: 9.00 num_pri: 2 hrs: Y off_fname: STEPHEN off_lname: MONTI off_title: EXECUTIVE V-P off_inst: 3550 off_addr_1: UNIV. OF TEXAS off_city: AUSTIN off_state: TX off_zip: 78712 off_country: USA off_phone: 512 471 4363 ! end of coverpage abstract: line_1: GHRS/G160M spectra of interstellar CO bands and atomic lines toward line_2: two stars will be analyzed to give the column density ratio 12C16O/ line_3: 13C16O and excitation temperatures for CO and C I. The ratio of column line_4: densities will not, in general, equal the 'true' 12C/13C ratio line_5: provided by optical spectroscopy of the CH+ molecular ion. The line_6: fractionation of CO is driven in opposite directions by isotopic line_7: charge exchange and selective photodissociation. The ratio 12C16O/ line_8: 13C16O for a known 12C/13C provides novel information on the physical line_9: conditions in a diffuse cloud. These conditions are also obtained line_10: from analysis of excitation. Since different probes sample different line_11: regions of a cloud, the structure of the cloud is discernible. The line_12: proposed experiment has been applied successfully by us to Zeta Oph's line_13: diffuse clouds. Now, we propose to use fractionation and excitation line_14: as new tools to probe other portions of the Rho Oph Molecular Cloud. ! ! end of abstract general_form_proposers: lname: LAMBERT fname: DAVID mi: L. inst: 3550 country: USA ! lname: SHEFFER fname: YARON inst: 3550 country: USA ! lname: FEDERMAN fname: STEVEN mi: R. inst: 3580 country: USA ! lname: GILLILAND fname: RONALD mi: L. inst: 3470 country: USA ! lname: CARDELLI fname: JASON mi: A. inst: 3884 country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Three regions will be observed with the GHRS, grating G160M and the line_2: SSA: 1442-1488A, 1385-1430A, and 1252-1293A. The 1465A observation line_3: provides the CO A-X 2-0 and 3-0 bands which are the optimum choice line_4: for the 13C16O (and 12C18O and 12C17O) bands. The 1270A observation line_5: covering the 10-0 and 11-0 bands provides weak 12C16O bands. It is line_6: the ratio of the 13C16O bands from 1465A spectra to the 12C16O bands line_7: from the 1270A spectra that provides the 12C16O/13C16O ratio. line_8: Furthermore, the 1405A observation includes the 4-0 and 5-0 bands, line_9: from which an accurate curve of growth for 13C16O is obtainable. Such line_10: a curve of growth allowed us to discern the presence of 12C18O line_11: toward Zeta Oph. The 1270A observations also contain a series of C I line_12: lines of varying strengths, including those from each level of the line_13: ground state, and the 1405 and 1465A spectra have several lines of line_14: S I and Ni II. A comparison of the column density from the weakest line_15: (unsaturated) lines with the estimates from moderately saturated line_16: lines yields a reliable estimate for the Doppler width. Exposure line_17: times have been estimated to give a detection limit of 0.3mA for line_18: the stars. The chosen limit is roughly 5 or more times smaller the line_19: predicted strength of a molecular band and allows detection of the line_20: weakest atomic features. line_22: As our GTO observations demonstrate, G160M provides adequate line_23: resolution if the S/N is sufficiently high. Attaining a S/N of order ! question: 3 section: 2 line_1: 500 requires that the observations be structured in such a way as to line_2: allow a robust, simultaneous solution for the stellar spectrum and line_3: any detector-dependent efficiency variations with wavelength as arise line_4: from photocathode granularity. The standard GHRS observing option, line_5: FP-SPLIT, allows S/N of a few hundred to be obtained, but can generate line_6: problems if the stellar spectrum happens to contain any spectral line_7: features with separations comparable to the carrousel stepping (about line_8: 5 diodes for FP-SPLIT=STD). To allow a robust separation of the line_9: observed spectra into the stellar and detector components, it is line_10: better to generate a super-FP-SPLIT in which FP-SPLIT sequences are line_11: obtained with wavelength settings incommensurate with structure in line_12: the stellar and detector spectra. A simultaneous solution (e.g., line_13: with a generalization of the technique given by Bagnuolo and Gies, line_14: 1991, ApJ, 376, 266) for the stellar and detector flat-field spectra line_15: can yield a S/N very close to that allowed by Poisson statistics line_16: (a S/N of 900 out of a Poisson limit of 950 has been demonstrated line_17: near 1465A with G160M). ! question: 4 section: 1 line_1: In principle, CO is observable from the ground through either the line_2: infrared vibration-rotation transitions or the mm/far-ir pure line_3: rotation transitions. For clouds like those in front of Zeta Oph, line_4: the fundamental V-R transitions at 5 microns should be detectable with line_5: the new generation of cryogenic echelle spectrometers such as the one line_6: at the IRTF. But 13C16O will be too weak to be detected. The mm line_7: also offers little hope of detection of fractionation from the line_8: ground; for example, Wilson et al. (1992, A&A, 262, 248) discuss a line_9: heroic search for the 13C16O J=1-0 line at 2.7 mm but were able to set line_10: the modest limit of 12C16O/13C16O > 60, a factor of ~ 2.5 below our line_11: HST measurement of 167. In addition, mm observations sample gas line_12: within a large beam and the detected clouds may not correspond to line_13: the clouds probed by absorption line spectroscopy. line_15: IUE certainly offers access to the A-X bands and the atomic line_16: transitions that we shall use, but it does not provide an adequate line_17: S/N. With the exception of the recent work on 20 Aql (Hanson et al. line_18: 1992, ApJ, 392, 571), no believable 12C16O/13C16O ratios have been line_19: provided from IUE. line_21: In short, fractionation of CO which can be determined only from HST line_22: spectroscopy provides information on physical conditions in a diffuse line_23: cloud that cannot be provided from observations of other molecules ! question: 4 section: 2 line_1: by ground-based telescopes. Furthermore, the atomic data can only line_2: be obtained through ultraviolet observations. ! question: 5 section: 1 line_1: None. ! question: 6 section: 1 line_1: None. ! ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: In anticipation of GTO1065, SV data of the CO A-X 5-0 and 6-0 bands line_2: were analyzed in conjunction with Wannier et al.'s (1982, ApJ, 254, line_3: 100) measurements of weak 12C16O bands. This analysis gave 12C16O/ line_4: 13C16O = 150. GTO observations with G160M yielded a refined value of line_5: 167. New results include an estimate of the 12C18O column density and line_6: information on excitation temperatures, as well as the first detection line_7: of interstellar Co+ and As+. These results are in press in ApJ. line_9: GTO1066 has provided echelle spectra of the C2 Mulliken bands and line_10: some data on the C2 F-X band with G160M. These data are now being line_11: analyzed. Apart from Zeta Oph, the targets for this program are stars line_12: low in CO and hence do not appear as targets here. line_14: The GHRS SAO and SV echelle data have provided accurate atomic and line_15: molecular abundances for the gas toward Xi Per and Zeta Oph. The line_16: atomic data reveal the presence of multiple component structure and line_17: allow for the quantitative analysis of the effects of differential line_18: depletion. The SV echelle data of Zeta Oph have provided the basis line_19: for and viability of the science proposed here. line_21: Other proposals/programs of the PI and Co-Is are not related to this line_22: one. ! question: 10 section: 1 line_1: Adequate computing facilities are available at all participating line_2: institutions. We anticipate requesting time at McDonald Observatory line_3: to complete the complementary ground-based spectroscopy of the program line_4: stars. ! !end of general form text general_form_address: lname: Lambert fname: David mi: L. category: PI inst: 3550 addr_1: Department of Astronomy addr_2: University of Texas city: Austin state: TX zip: 78712 country: USA phone: 512-471-7438 telex: DLL@ASTRO.AS.UTEXAS.EDU ! lname: category: CON ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HD147933 name_2: RHO-OPH-A name_3: GSC6794/0549 descr_1: A; 110 pos_1: RA = 16H 25M 35.15S +/- 0.01S, pos_2: DEC = -23D 26' 49.8" +/- 0.15" equinox: 2000 pm_or_par: N rv_or_z: V=-15.0 acqpr_1: COMP comment_1: THIS IS THE BRIGHTER MEMBER OF A comment_2: DOUBLE STAR. SEPARATION IS comment_3: 3.2" AND BRIGHTNESS DIFFERENCE comment_4: IS 0.9 MAG. comment_5: UV FLUXES FROM TD-1 AND comment_6: GAMMA-PEG (FROM OAO-2). comment_7: POS. FROM GSC/HIPPARCHOS DATABASE comment_8: STAR IS SAO NO. 184382. fluxnum_1: 1 fluxval_1: V=5.02,TYPE=B2IV fluxnum_2: 1 fluxval_2: B-V=+0.24 fluxnum_3: 2 fluxval_3: E(B-V)=0.47 fluxnum_4: 3 fluxval_4: F-CONT(1270)=4.6+/-0.5E-10 fluxnum_5: 4 fluxval_5: F-CONT(1405)=5.4+/-0.5E-10 fluxnum_6: 5 fluxval_6: F-CONT(1465)=5.4+/-0.5E-10 ! targnum: 2 name_1: HD148184 name_2: CHI-OPH name_3: GSC6207/1170 descr_1: A; 110 pos_1: RA = 16H 27M 1.44S +/- 0.01S, pos_2: DEC = -18D 27' 22.6" +/- 0.17" equinox: 2000 pm_or_par: N rv_or_z: V=-15.0 comment_1: UV FLUXES FROM OAO-2. comment_2: POSITION FROM GSC HIPPARCHOS comment_3: STAR IS SAO NO. 159918. fluxnum_1: 1 fluxval_1: V=4.42,TYPE=B2IV fluxnum_2: 1 fluxval_2: B-V=+0.28 fluxnum_3: 2 fluxval_3: E(B-V)=0.53 fluxnum_4: 3 fluxval_4: F-CONT(1270)=5.2+/-0.7E-10 fluxnum_5: 4 fluxval_5: F-CONT(1405)=4.8+/-0.4E-10 fluxnum_6: 5 fluxval_6: F-CONT(1465)=4.7+/-0.3E-10 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: STOBSG targname: # config: HRS opmode: ACCUM aperture: 0.25 sp_element: # wavelength: 1.0 num_exp: # time_per_exp: 108.8S s_to_n: 100 s_to_n_time: 20M fluxnum_1: # priority: # param_1: FP-SPLIT=STD param_2: STEP-PATT=5 ! linenum: 2.000 targname: HD147933 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 5.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN, param_3: LOCATE=YES req_1: ONBOARD ACQ FOR 2.1; req_2: CYCLE 4 / 2.0-9.2 comment_1: CENTER IN LSA comment_2: EXPECT ABOUT 3000 CTS/0.2S STEP ! linenum: 2.100 targname: HD147933 config: HRS opmode: ACQ/PEAKUP aperture: 0.25 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 5.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5 req_1: ONBOARD ACQ FOR 5.1-9.2; ! linenum: 5.100 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1464.8 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 5.300 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1466.8 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 5.400 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1461.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 5.500 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1471.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 7.000 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1403.1 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 7.100 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1405.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 7.200 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1407.9 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 9.000 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1271.1 num_exp: 3 time_per_exp: X5 fluxnum_1: 3 priority: 1 ! linenum: 9.100 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1273.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 3 priority: 1 ! linenum: 9.200 sequence_1: USE sequence_2: STOBSG targname: HD147933 sp_element: G160M wavelength: X1275.9 num_exp: 3 time_per_exp: X5 fluxnum_1: 3 priority: 1 ! linenum: 12.000 targname: HD148184 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 5.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN, param_3: LOCATE=YES req_1: ONBOARD ACQ FOR 12.1; req_2: CYCLE 4 / 12.0-19.2 comment_1: CENTER IN LSA comment_2: EXPECT ABOUT 3000 CTS/0.2S STEP ! linenum: 12.100 targname: HD148184 config: HRS opmode: ACQ/PEAKUP aperture: 0.25 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 5.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=5 req_1: ONBOARD ACQ FOR 15.1-19.2; ! linenum: 15.100 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1464.8 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 15.300 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1466.8 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 15.400 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1461.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 15.500 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1471.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 5 priority: 1 ! linenum: 17.000 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1403.1 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 17.100 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1405.0 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 17.200 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1407.9 num_exp: 3 time_per_exp: X5 fluxnum_1: 4 priority: 1 ! linenum: 19.000 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1271.1 num_exp: 3 time_per_exp: X5 fluxnum_1: 3 priority: 1 ! linenum: 19.100 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1273.0 num_exp: 3 time_per_exp: X4 fluxnum_1: 3 priority: 1 ! linenum: 19.200 sequence_1: USE sequence_2: STOBSG targname: HD148184 sp_element: G160M wavelength: X1275.9 num_exp: 3 time_per_exp: X5 fluxnum_1: 3 priority: 1 ! ! end of exposure logsheet ! No scan data records found