! File: 4272C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:19:51:10 coverpage: title_1: SUPERSONIC CHROMOSPHERIC WINDS CYC3-MED sci_cat: COOL STARS sci_subcat: STELLAR ATMOSPHERES proposal_for: GO pi_fname: ANDREA pi_mi: K. pi_lname: DUPREE pi_inst: SMITHSONIAN ASTROPHYSICAL OBSERVATORY pi_country: USA hours_pri: 7.25 num_pri: 1 hrs: Y funds_length: 12 off_fname: IRWIN off_mi: I. off_lname: SHAPIRO off_title: DIRECTOR off_inst: 2166 off_addr_1: 60 GARDEN STREET off_addr_2: MS 45 off_city: CAMBRIDGE off_state: MA off_zip: 02138 off_country: USA off_phone: 617-495-7100 ! end of coverpage abstract: line_1: We have discovered supersonic wind velocities in the chromosphere of line_2: the hybrid supergiant star: Alpha Aquarii (HD 209750; G2Ib). These line_3: mass motions in excess of the photospheric escape velocity are evident line_4: in the profile of the He I 10830A line, and confirmed by our model line_5: calculations. Such supersonic motion of a wind profoundly impacts line_6: the velocity profile and energy requirements of stellar winds and line_7: subsequent mass loss. We are proposing HST spectroscopic line_8: observations of Alpha Aqr in order to obtain line profiles and line_9: velocity shifts of transition region lines to identify the emitting line_10: region, to define the wind acceleration profile, and to settle line_11: long-standing controversies about the wind temperature. ! ! end of abstract general_form_proposers: lname: DUPREE fname: ANDREA title: PI mi: K. inst: SMITHSONIAN ASTROPHYSICAL OBSERVATORY country: USA ! lname: WHITNEY fname: BARBARA mi: A. inst: SMITHSONIAN ASTROPHYSICAL OBSERVATORY country: USA ! lname: SASSELOV fname: DIMITAR mi: D. inst: SMITHSONIAN ASTROPHYSICAL OBSERVATORY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We propose to use the GHRS at medium resolution, G160M grating in line_2: order to measure the line widths, line positions, and flux of 4 line_3: transitions in the spectrum of Alpha Aquarii: N V (center at line_4: 1240.8A), C II (center at 1335.1A), C IV (center at 1549.5A), He line_5: II (center at 1652.0A). A wavelength calibration will be taken line_6: before each spectral line observation. ! question: 4 section: 1 line_1: Ultraviolet spectra are required to study the transition regions line_2: and winds of cool stars because the important resonance line_3: transitions at these temperatures occur in the ultraviolet. The line_4: capabilities of HST are required for the spectral resolution line_5: necessary to identify the He II line and to determine the line line_6: profiles of the transition region lines. Spectra from IUE have line_7: been obtained at low dispersion (about 6 Angstrom resolution), and line_8: fluxes can be extracted in cases where blends are not present. line_9: However the region near the He II feature also contains line_10: transitions of Si I, S I, and C I, and no certain identification line_11: can be made from low dispersion spectra. Moderate dispersion is line_12: necessary to detect the He II line. The line profiles are needed line_13: of the resonance transitions: C II, C IV, and N V. We have pushed line_14: IUE to the limit, obtained a 13 hour exposure on Alpha Aqr, but line_15: these lines, or even faint smudges at the appropriate positions, line_16: are not visible on the photowrite image nor on a digital display. line_17: The line profiles, accessible only with HST, are needed to line_18: substantiate and extend the velocity profile to higher line_19: temperatures. line_20: Alpha Aqr has been observed with IUE frequently. After defining line_21: the class of hybrid stars (Hartmann, Dupree, and Raymond 1980), we line_22: were the first to note changes in the Mg II profile using IUE data line_23: (Dupree and Baliunas 1979). Others have also remarked on the ! question: 4 section: 2 line_1: variability of transition region line fluxes and identified a line_2: period of variation (Broscius, Mullan, and Stencel 1985). line_3: Alpha Aqr is included in the SAO-Mt. Wilson HK Program, and has line_4: been monitored from 1983 to the present time in the Ca II H and K line_5: lines near lambda 3900 which act as the tracers of photospheric line_6: magnetic fields. A search for periodicities in a 5-year time line_7: series revealed (Rao et al. 1993) that both long (approximately line_8: 400 days) and short (approximately 75 days) period variations are line_9: present. The longer periods may be ascribed to rotation; the line_10: shorter period may reflect episodic behavior, possibly related to line_11: pulsation. Because the discovery of a long period demonstrates line_12: the presence of rotation markers on the surface, Rao et al. (1993) line_13: conclude that magnetic structures are present in the atmospheres line_14: of these supergiant stars. This offers the possibility that line_15: magnetic loops are the source of the C IV emission; this line_16: observation also makes plausible the channeling and acceleration line_17: of a stellar wind, and the potential for heating and momentum line_18: deposition by a magnetically associated process such as Alfven line_19: waves. The short-period variations may be connected with the line_20: rapid acceleration we have found from modeling the He I lambda line_21: 10830 line discussed in Item 1, above. line_22: To follow up on the short-term atmospheric variability of Alpha line_23: Aqr, we have carried out an IUE program to monitor this star every ! question: 4 section: 3 line_1: ten days for a period of 70 days in 1991. Fluxes of chromospheric line_2: and transition region lines were obtained as well as Mg II line line_3: profiles. Simultaneously, we obtained spectra at H alpha, Ca K line_4: (from Oak Ridge Observatory, F. L. Whipple Observatory, David line_5: Dunlop Observatory), He I (lambda 10830) (from the line_6: Canada-France-Hawaii Telescope) and HK fluxes (from Mt. Wilson), line_7: giving us a solid idea of the time variability of the atmosphere. line_8: While these spectral features provide enough information on the line_9: time-dependent dynamics of the atmosphere, the HST line profile line_10: observations are the crucial physical constraint to the mechanisms line_11: responsible for that dynamics. For practical purposes, the HST line_12: observations should ensure the uniqueness of our atmospheric line_13: modeling. ! question: 4 section: 4 line_1: We propose to observe 1 star: Alpha Aquarii (HD 209750; G2 Ib; V= line_2: 2.90; B-V= +0.98). Fluxes and line profiles will be obtained line_3: using the GHRS, Grating 160M at 4 different grating positions. line_4: Total required integration times will be accomplished with 15 line_5: minute segments. line_6: The flux in three of our target lines, C II, C IV, and N V, has line_7: been measured (an upper limit exists for He II) from low line_8: dispersion IUE spectra (Hartmann et al. 1980, 1982). An average line_9: of the two values was taken. These fluxes represent the flux in line_10: the multiplet, so we have assumed optically thin ratios (2:1, for line_11: the Li-like series; and according to statistical weight for C II) line_12: to estimate the flux in the strongest component of the multiplet. line_13: It is also necessary to estimate the line width, which we take as line_14: 1 Angstrom, based on measures of transition region line profiles line_15: in a hybrid giant, Alpha TrA (Hartmann et al. 1981), and confirmed line_16: by examination of S I and Si II profiles in Alpha Aqr from our line_17: high dispersion IUE spectrum. line_18: The sensitivity for the HRS Grating G160M, 2'' Aperture, at the line_19: wavelengths of interest is given (GHRS Instrument Handbook, line_20: Version 3.0, Jan. 1992, Table 4-13, p. 45) for the combined OTA + line_21: aperture + HRS system. To estimate the exposure time to achieve a line_22: signal-to-noise of about 20, under conditions when neither line_23: scattered light nor dark count is important, Equation 4-5 in the ! question: 4 section: 5 line_1: GHRS Instrument Handbook (3.0) applies: R^2 = s n_s t, where R is line_2: the signal to noise ratio, n_s is the number of bins (n_s =1), s line_3: is the count rate from the star at the Earth, and t is the line_4: integration time. line_5: We summarize the parameters for the four observations in the Table line_6: below and an evaluation of the necessary time for each one. A line_7: total of 7.25 hours of primary integration time results. line_8: Line lambda(Angstrom) Obs. Flux S^dagger Count Rate Time line_9: erg cm^-2 (cts/diode/s) (hrs) line_10: s^-1 line_11: Angstrom^-1 line_12: N V 1238.8 1.3 x 10^-13 4.0 5.3 x 10^-2 2.10 line_13: C II 1334.5 1.3 x 10^-13 6.0 7.8 x 10^-2 1.40 line_14: C IV 1548.2 2.0 x 10^-13 4.4 8.8 x 10^-2 1.30 line_15: He II 1640.5 <1.0 x 10^-13 4.6 4.6 x 10^-2 2.45 line_16: dagger: G160M grating Sensitivity: 10^11 counts diode^-1 line_17: /erg cm^-2 s^-1 Angstrom^-1. ! question: 5 section: 1 line_1: Please schedule between May 10 and November 1, 1993 so that IUE line_2: can be used simultaneously. Advance notice would help us organize line_3: the simultaneous ground-based spectroscopy. ! question: 6 section: 1 line_1: Wavelength calibrations necessary before each set of spectral line line_2: observations in order to obtain precise Doppler shifts of emission line_3: features. ! question: 7 section: 1 line_1: The ultraviolet spectra from HST will be reduced at the Solar and line_2: Stellar Division Computer Facility at the Center for Astrophysics line_3: which has established several standard spectroscopic reduction line_4: programs (IRAF and IDL) in addition to codes especially developed line_5: to reduce and analyze IUE ultraviolet spectroscopic data. line_6: Spectral deconvolution will be carried out to recover from the line_7: spherical aberration of the primary mirror of HST. We are aware line_8: of the procedures being tested both by the GHRS team and line_9: scientists at the STScI. In addition, we plan to consult with line_10: other scientists in the SSP Division here who have much experience line_11: in deconvolution of images and spectra both for speckle imaging line_12: and interferometry. We will acquire spectra with S/N of 20 or line_13: more to make this possible. Line fluxes and line centers will be line_14: determined using the HRS calibration and the various routines line_15: available in these reduction packages. In the past, we have line_16: routinely reduced IUE as well as MMT and FLWO 1.5-m echelle line_17: spectra with these packages. The optical data (H alpha, Ca II, He line_18: I) will have a first reduction at the observatories where they are line_19: acquired and then will be incorporated into the analysis at the line_20: Center for Astrophysics. line_21: Our goal is to find what physical mechanism heats these hybrid line_22: atmospheres, where in the atmospheres acceleration occurs, and line_23: which physical mechanisms produce winds in luminous cool stars. We ! question: 7 section: 2 line_1: believe that the answer to ``where ?'' is to be found in the line_2: observational data. We shall compute detailed synthetic spectra line_3: (line profiles) from time-dependent atmospheres to match the data. line_4: Our atmospheric models will be neither in radiative nor in line_5: dynamical equilibrium, and will assume spherical symmetry. line_6: The first models thus constrained by the available observations line_7: will be used to define the physics of wind acceleration. Our line_8: ability to treat explicitly different physical mechanisms and to line_9: compute synthetic spectra will be used to make predictions about line_10: the behavior of certain lines and to find sensitive spectral line_11: features for model verification. As a result we shall reject or line_12: accept a certain model. The rejected models (due to lack of a line_13: unique solution or due to missing physics) will be initialized line_14: again. The accepted models will hopefully offer answers to the` line_15: `which mechanisms?'' question. line_16: A semi-empirical spherically symmetric atmosphere built by the line_17: code PANDORA (Avrett and Loeser 1992) begins the process. This line_18: code solves the non-LTE radiative transfer equations, including line_19: the effects of expansion and spherical geometry on the line source line_20: function, as well as the emergent profiles. Parameters of the line_21: atmosphere are constrained by observed fluxes and profiles of line_22: chromospheric lines such as H alpha, Ca K, He I and Mg II, and line_23: transition region lines measured by IUE. An Alpha Aqr model has ! question: 7 section: 3 line_1: been constructed (Dupree et al. 1992) and is necessary for line_2: interpretation of profiles rather than plane-parallel static line_3: models (Harper 1992). line_4: This initial atmosphere becomes the input for the code HERMES line_5: (Sasselov and Raga, 1992), which computes a time-dependent model line_6: of the atmosphere. HERMES is a Lagrangian hydrodynamic scheme of line_7: second order (Godunov technique) with iterative and simultaneous line_8: non-LTE radiative transfer calculations by a version of the code line_9: MULTI (Carlsson, 1986; Uitenbroek, 1990). The output of HERMES line_10: contains time-dependent line profiles for a number of species line_11: which can be matched to observed spectra. line_12: The software described in our overall plan above is already line_13: developed. At this point, we plan to use linearized theory for line_14: Alfven wave dissipation, and to include the effects of dust as a line_15: momentum transfer term with a prescribed cross section. Our method line_16: and HERMES will easily allow further sophistication of the input line_17: physics. ! question: 8 section: 1 line_1: We will make coordinated spectroscopic observations from the line_2: ground (Ca II, H alpha, He I), and will apply for time on IUE to line_3: obtain transition region fluxes and line profiles of the Mg II line_4: emission. Because IUE has Beta-angle constraints on its target, line_5: scheduling between May 10 and November 1 is optimum. As much line_6: advance notice as possible would be helpful. line_7: The Mt. Wilson HK program will continue to follow Alpha Aqr line_8: through 1993 so that its variations are well documented. ! question: 9 section: 1 line_1: Program No. 2693: A Search for Mass Loss from Two Red Giants in line_2: NGC 6752, (A. K. Dupree, PI). This small (< 10 hrs) program line_3: obtained Mg II profiles for two red giants, A31 and A59, in the line_4: globular cluster NGC 6752. line_5: Observations were made in April 1992. The data were received in line_6: May 1992, and we are in the process of reducing it along with the line_7: contemporaneous ground-based spectra. line_8: This program is not related to the present proposal. ! question: 10 section: 1 line_1: The Smithsonian Institution provides a full (12-month) salary and line_2: benefits for A. K. Dupree, the Principal Investigator. The line_3: Smithsonian Institution also provides a full (2-month) salary and line_4: benefits for D. D. Sasselov who is a Harvard-Smithsonian Center line_5: for Astrophysics PostDoctoral Fellow until the Summer of 1993. line_6: Computer facilities, and the people responsible for system line_7: operations in the Solar and Stellar Physics Division of the Center line_8: for Astrophysics have been provided by the Smithsonian line_9: Institution. Our Division maintains a UNIX-based Local Area line_10: Network of SUN Workstations. The SSP Divisional Computer System line_11: currently is comprised of 4 SUN4 servers providing disk services line_12: to approximately 26 client workstations. The workstations provide line_13: text processing and connectivity to divisional scientists. They line_14: are also used for running code that does not require large memory line_15: or disk space and which does not require a fast SUN machine to line_16: complete a run in a reasonable amount of time. Our proposed model line_17: analysis of the HST data will require a faster, dedicated machine, line_18: and more disk space than is now available. We hope to acquire line_19: some of this hardware as a part of our Cycle 1 HST Program. line_20: Standard reduction and software packages (IRAF, IDL, MAXIMA, line_21: MONGO, AIPS, ...) have been provided by the Smithsonian line_22: Institution, and are maintained and updated by the system staff as line_23: necessary. However, for specific applications of interactive ! question: 10 section: 2 line_1: reduction, deconvolution, analysis, and model-building pertaining line_2: to our proposal, we must appoint people using funds from outside line_3: grants. Similarly, postdoctoral scientists, and students from line_4: Harvard University and elsewhere must be hired with grant funds. ! !end of general form text general_form_address: lname: DUPREE fname: ANDREA mi: K. category: PI inst: Smithsonian Astrophysical Observatory addr_1: SMITHSONIAN ASTROPHYSICAL OBSERVATORY addr_2: 60 GARDEN STREET, MS-15 city: CAMBRIDGE state: MA zip: 02138 country: USA phone: 617-495-7489 telex: 921428 SATELLITE CAM ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HD209750 name_2: ALPHA-AQR name_3: GSC-5224-1806 descr_1: A,138 pos_1: RA = 22H 05M 46.93S +/-0.007S, pos_2: DEC = -00D 19' 10.9" +/-0.1" equinox: 2000. rv_or_z: V = +8 fluxnum_1: 1 fluxval_1: V=2.90,TYPE=G2IB fluxnum_2: 2 fluxval_2: B-V=+0.98 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: HD209750 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 1.8S priority: 1 param_1: BRIGHT=RETURN param_2: MAP=DEF param_3: SEARCH-SIZE=3 req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 2; req_3: GROUP 1-10 WITHIN 30H comment_1: STEP-TIME=200MS ! linenum: 2.000 targname: HD209750 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 163.2S priority: 1 req_1: CYCLE 3; req_2: ONBOARD ACQ FOR 3-10; comment_1: STEP-TIME=1.6S ! linenum: 3.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1651.0 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=3 req_1: CALIB FOR 4 NO SLEW; req_2: SEQ 3-4 NO GAP; req_3: CYCLE 3 ! linenum: 4.000 targname: HD209750 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1651.0 num_exp: 15 time_per_exp: 10M priority: 1 param_1: STEP-PATT=5 req_1: CYCLE 3 ! linenum: 5.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1549.5 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=3 req_1: CALIB FOR 6 NO SLEW; req_2: SEQ 5-6 NO GAP; req_3: CYCLE 3 ! linenum: 6.000 targname: HD209750 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1549.5 num_exp: 8 time_per_exp: 10M priority: 1 param_1: STEP-PATT=5 req_1: CYCLE 3 ! linenum: 7.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1335.1 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=3 req_1: CYCLE 3; req_2: CALIB FOR 8 NO SLEW; req_3: SEQ 7-8 NO GAP ! linenum: 8.000 targname: HD209750 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1335.1 num_exp: 8 time_per_exp: 10M priority: 1 param_1: STEP-PATT=5 req_1: CYCLE 3 ! linenum: 9.000 targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G160M wavelength: 1233.0 num_exp: 1 time_per_exp: DEF priority: 1 param_1: STEP-PATT=3 req_1: CYCLE 3; req_2: CALIB FOR 10 NO SLEW; req_3: SEQ 9-10 NO GAP ! linenum: 10.000 targname: HD209750 config: HRS opmode: ACCUM aperture: 2.0 sp_element: G160M wavelength: 1233.0 num_exp: 13 time_per_exp: 10M priority: 1 param_1: STEP-PATT=5 req_1: CYCLE 3 ! ! end of exposure logsheet ! No scan data records found