! $Id: 5317,v 9.1 1994/07/27 16:30:42 pepsa Exp $ coverpage: title_1: SEARCHING FOR CIRCUMSTELLAR GAS AROUND LOW MASS title_2: PRE-MAIN SEQUENCE STARS: CYCLE 4 MEDIUM sci_cat: COOL STARS sci_subcat: EARLY EVOLUTION proposal_for: GO pi_fname: FREDERICK pi_mi: M. pi_lname: WALTER pi_inst: STATE UNIVERSITY OF NEW YORK, STONY BROOK pi_country: USA pi_phone: 516-632-8232 hours_pri: 19.70 num_pri: 4 hrs: Y ! end of coverpage abstract: line_1: We seek evidence of the presence of gas disks around low mass pre-main line_2: sequence stars. We know that the dust disks disappear rapidly, changing line_3: from optically thick to undetectable in less than 1 Myr. Few stars older line_4: than 10 Myr retain dust disks. The gas may linger longer, but there is line_5: yet no evidence for circumstellar gas around naked (dustless) T Tauri line_6: stars. We propose to search for H2 emission from the UV Lyman band, which line_7: arises from fluorescently excited molecular hydrogen at 1000-2000K. Such line_8: emission has been seen in T Tauri, and in Herbig-Haro objects. With the line_9: GHRS we can detect H2 emission a fraction of a percent of the intensity line_10: observed in T Tauri. This UV search is more sensitive than radio and line_11: infrared searches for molecular gas. We propose to observe 4 early-mid line_12: G stars ranging in age from 1 to 200 Myr. Some have dust disks, most do line_13: not. These observations will permit us to discriminate between scenarios line_14: where the disk dissipates completely, and one where the dust accumulates line_15: into planetesimals while the gaseous disk remains in place. Disk mass line_16: estimates based on the H2 will permit estimation of the true timescales line_17: for the dissipation of the circumstellar disks; non-detection will line_18: indicate that either the gas also dissipates quickly, or that the line_19: optically thin circumstellar gas disks do not extend in close to the st line_20: This investigation may constrain theories of planetary accumulation. ! ! end of abstract general_form_proposers: lname: WALTER fname: FREDERICK mi: M. inst: 2988 country: USA ! lname: BROWN fname: ALEXANDER inst: 1764 country: USA ! lname: BENNETT fname: PHILIP inst: 1764 country: USA ! lname: LISSAUER fname: JACK mi: J. inst: 2988 country: USA ! lname: MILLAR fname: THOMAS inst: 8046 country: UK esa: Y ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: The observations are straightforward. In general, acquisitions are line_2: handled in sequence NTTS-ACQ. Acquisitions and peakups will use mirror line_3: N2, except for target HD115043, where PEAKUP will use the A2 mirror line_4: because the star is too bright for the 1.6s step-time used for PEAKUP. line_5: We will then switch sides to take 2 exposures with G140L line_6: through the LSA. The two exposures, centered at 1300A and 1570A, line_7: will cover the 1170-1700A region containing the H2 bands. We will line_8: read the spectra out about every 6 minutes (every line_9: 12 substep patterns) to negate the effects of GIMP. The sequences line_10: NTTS-H2A and NTTS-H2B handle the exposures and associated WAVE line_11: exposures. line_12: We will also observe target BD+19D706 in the SSA. After the LSA line_13: exposures (lines 14.0-14.2), we do an ACQ/PEAKUP into the SSA line_14: and repeat the spectral sequence. ! question: 4 section: 1 line_1: The H2 Lyman bands fall in the far-UV, between 1000 and 1700A. IUE line_2: is not sufficiently sensitive to detect these emissions, except in line_3: the extreme cases of the H-H objects and T Tau (where the H2 emission line_4: is likely shocked gas from an H-H object). Limits on the H2 emission line_5: from CTTS (including RW Aur, BP Tau, and DG Tau) and NTTS (HD142361, line_6: HDE283572) are a factor of 8-10 lower than the flux levels of line_7: 5-10x10^-14 erg/cm/cm/s seen in T Tau. We can detect lines with line_8: integrated fluxes of 10^(-16) erg/cm/cm/s. This is 2-3 orders of line_9: magnitude larger than the expected H2 emission from the starspots, line_10: scaling the solar observations to starspot filling factors of 20-30% line_11: and the larger stellar radii. line_12: For a minimum mass nebula (0.01 solar masses) with a power law line_13: surface density of index -7/4, about 10^30 gm of H2 can potentially line_14: radiate in the Lyman bands. An efficiency of Lyman alpha fluorescent line_15: pumping of 10^(-4) will result in detectable H2 Lyman band fluxes of line_16: order 10^(-16) erg/cm/cm/s. line_17: This program requires use of side 1 and G140L. The medium line_18: resolution modes do not have the wavelength coverage to observe more line_19: than a single line in each observation. We require observations of a line_20: number of the lines to determine the excitation mechanism. The FOS line_21: cannot be used because of its red leak. line_22: We are also studying the dust disks, by refining our IRAS upper line_23: limits for these stars (Wolk & Walter 1993), and by improving our ! question: 4 section: 2 line_1: models of the spectral energy distributions by accounting for line_2: starspots. We plan TiO band spectroscopy to determine starspot filling line_3: factors directly. One of us (FMW) is also a co-I on an ISO key project line_4: which will include deep exposures of selected NTTS. None of these line_5: investigations is sensitive to the gas, the majority species in the line_6: circumstellar disk. We propose these HST observations to round out line_7: the picture. ! question: 5 section: 1 line_1: We specify the GROUP special requirement in lines line_2: 10.2, 12.1, 13.1, 14.1, and 14.3 to ensure that line_3: the two spectra of each target are obtained reasonably close together line_4: in time. These stars are variable, and proper interpretation of the H2 line_5: line ratios requires that we minimize the possibility of time line_6: variability. Interruptions due to earth occultation and SAA passages line_7: are expected; we do NOT want the observations of an individual star line_8: spread over many days. ! question: 6 section: 1 line_1: We request standard WAVE exposures accompanying each ACCUM exposure. line_2: This provides the best possible offsets for wavelength calibration. ! ! question: 8 section: 1 line_1: There is no need for coordinated observations for our primary line_2: scientific goal, which is to detect circumstellar gas or place line_3: stringent upper limits on it. However, we will attempt to obtain line_4: contemporaneous ground based spectra in order to fully utilize the line_5: information contained in the chromospheric lines. line_7: All of these stars are in the Guide Star Catalog, and hence have line_8: accurate coordinates. ! question: 9 section: 1 line_1: 1208 Doppler Imaging of the Chromospheres and Transition Regions of line_2: AR Lacertae; F.M. Walter line_4: 1209/3949 Non-radiative Heating in Pre-Main Sequence Stars; F.M. Walter line_6: 1210/3950 Age Dependence of Non-radiative Heating in Stellar line_7: Chromospheres; F.M. Walter line_9: 3482 The Nature of the Variable Infalling Material on the Star Beta line_10: Pictoris; A. Vidal-Madjar P.I., J. Lissauer U.S. Administrative line_11: PI, many co-Is. Data were obtained in December 1992 and are line_12: being reduced and analyzed. line_14: None of the above proposals are related to this proposal. However, the line_15: ancillary data from this proposal on the chromospheric emisssion line_16: lines will augment the higher resolution data on 2 T Tauri stars line_17: being collected in program 1209/3949. ! question: 10 section: 1 line_1: We have computing facilities at SUNY and JILA to undertake the data line_2: analysis and model computations. We have access to the full range of line_3: GHRS-related software written by the GHRS team. line_5: We request funding to support a full time graduate student at SUNY, line_6: and partial salary support for the US investigators. line_8: The PI will contribute up to 5% of his time during the academic year line_9: to the program, at no cost to the project. ! !end of general form text general_form_address: lname: Walter fname: Frederick mi: M. category: PI inst: 2988 addr_1: Dept of Earth and Space Sciences addr_2: Z=2100 addr_3: State University of New York city: Stony Brook state: NY zip: 117942100 country: USA phone: (516)632-8232 telex: fwalter@sbast1.ess.sunysb.edu ! lname: category: CON ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: BD+30D743 name_2: SU-AURIGAE name_3: GSC977-2387 descr_1: A,156,137,904,906 pos_1: PLATE-ID=02TR, pos_2: RA = 4H 55M 59.26S +/- 0.3", pos_3: DEC = 30D 34' 1.9" +/- 0.3" equinox: J2000 comment_1: F(1400) IS LIMITING FLUX WE EXPECT comment_2: TO ACHIEVE IF H2 EMISSION IS NOT comment_3: DETECTED fluxnum_1: 1 fluxval_1: V = 10.5 +/- 0.8 fluxnum_2: 1 fluxval_2: B-V = 0.90 +/- 0.1 fluxnum_3: 2 fluxval_3: A(V) = 1.0 +/- 0.5 fluxnum_4: 3 fluxval_4: F(1400) = 2 +/- 1E-16 fluxnum_5: 4 fluxval_5: F-LINE(1335)=34 +/- 3E-15 ! targnum: 2 name_1: BD+27D657 name_2: V987-TAU name_3: GSC1828-481 descr_1: A,156,137,904 pos_1: PLATE-ID=0051, pos_2: RA = 4H 21M 58.88S +/- 0.3", pos_3: DEC = 28D 18' 6.88" +/- 0.3" equinox: J2000 comment_1: F(1400) IS LIMITING FLUX WE EXPECT comment_2: TO ACHIEVE IF H2 EMISSION IS NOT comment_3: DETECTED fluxnum_1: 1 fluxval_1: V = 9.04 +/- 0.1 fluxnum_2: 1 fluxval_2: B-V = 0.83 +/- 0.02 fluxnum_3: 2 fluxval_3: A(V) = 0.4 +/- 0.2 fluxnum_4: 3 fluxval_4: F(1400) = 2+/-1E-16 fluxnum_5: 4 fluxval_5: F-LINE(1335) = 36 +/- 8 E-15 ! targnum: 3 name_1: HD142361 name_2: CD-23D12575 name_3: GSC6779-1372 descr_1: A,156,137,904 pos_1: PLATE-ID=01VY, pos_2: RA = 15H 54M 59.92S +/- 0.5", pos_3: DEC = -23D 47' 18.42" +/- 0.5" equinox: J2000 comment_1: F(1400) IS LIMITING FLUX WE EXPECT comment_2: TO ACHIEVE IF H2 EMISSION IS NOT comment_3: DETECTED fluxnum_1: 1 fluxval_1: V = 8.96 +/- 0.01 fluxnum_2: 1 fluxval_2: B-V = 0.67 +/- 0.02 fluxnum_3: 2 fluxval_3: E(B-V)=0.07 +/- 0.03 fluxnum_4: 3 fluxval_4: F(1400) = 2+/-1E-16 fluxnum_5: 4 fluxval_5: F-LINE(1335) = 8 +/- 1 E-14 ! targnum: 4 name_1: HD115043 name_2: GSC3846-925 descr_1: A,156,137 pos_1: RA = 13H 13M 36.92S +/- 0.2", pos_2: DEC = 56D 42' 29.09" +/- 0.2" equinox: J2000 comment_1: F(1400) IS LIMITING FLUX WE EXPECT comment_2: TO ACHIEVE IF H2 EMISSION IS NOT comment_3: DETECTED. comment_4: STANDARD ACTIVE-CHROMOSPHERE STAR. fluxnum_1: 1 fluxval_1: V = 6.85 +/- 0.01 fluxnum_2: 2 fluxval_2: B-V = 0.61 +/- 0.1 fluxnum_3: 3 fluxval_3: E(B-V)= 0.0 +/- 0.1 fluxnum_4: 4 fluxval_4: F(1400) = 4+/-1E-16 ! targnum: 5 name_1: BD+19D706 name_2: T-TAURI name_3: GSC1272-470 descr_1: A,156,137,904,906 pos_1: PLATE-ID=000O, pos_2: RA = 4H 21M 59.40S +/- 0.3", pos_3: DEC = 19D 32' 7.5" +/- 0.3" equinox: J2000 comment_1: F(1400) IS LIMITING FLUX WE EXPECT comment_2: TO ACHIEVE IF H2 EMISSION IS NOT comment_3: DETECTED. fluxnum_1: 1 fluxval_1: V = 10.3 +/- 0.7 fluxnum_2: 1 fluxval_2: B-V = 1.20 +/- 0.2 fluxnum_3: 2 fluxval_3: A(V) = 1.0 +/- 0.5 fluxnum_4: 3 fluxval_4: F(1400) = 8 +/- 1E-16 fluxnum_5: 4 fluxval_5: F-LINE(1335)=34 +/- 3E-15 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: NTTS-ACQ targname: # config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 9S priority: 1 param_1: BRIGHT=RETURN, param_2: SEARCH-SIZE=3 req_1: ONBOARD ACQ FOR 1.1 comment_1: STEP-TIME=1.0S ! linenum: 1.100 sequence_1: DEFINE sequence_2: NTTS-ACQ targname: # config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 163.2S priority: 1 comment_1: STEP-TIME=1.6S ! linenum: 2.000 sequence_1: DEFINE sequence_2: NTTS-H2A targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G140L wavelength: 1300 num_exp: 1 time_per_exp: 30S priority: 3 param_1: STEP-PATT=2 req_1: CALIB FOR 2.1 NO SLEW ! linenum: 2.100 sequence_1: DEFINE sequence_2: NTTS-H2A targname: # config: HRS opmode: ACCUM aperture: # sp_element: G140L wavelength: 1300 num_exp: # time_per_exp: 353.6S s_to_n: 3.0 fluxnum_1: 3 fluxnum_2: 4 priority: 1 param_1: STEP-PATT=5 comment_1: S/N IS NOT STRICTLY RELEVANT. THIS IS comment_2: A SEARCH FOR WEAK EMISSION LINES comment_3: OR UPPER LIMITS TO THE H2 FLUX. ! linenum: 3.000 sequence_1: DEFINE sequence_2: NTTS-H2B targname: WAVE config: HRS opmode: ACCUM aperture: SC2 sp_element: G140L wavelength: 1570 num_exp: 1 time_per_exp: 30S priority: 3 param_1: STEP-PATT=2 req_1: CALIB FOR 3.1 NO SLEW ! linenum: 3.100 sequence_1: DEFINE sequence_2: NTTS-H2B targname: # config: HRS opmode: ACCUM aperture: # sp_element: G140L wavelength: 1570 num_exp: # time_per_exp: 353.6S s_to_n: 3.0 priority: 2 param_1: STEP-PATT=5 comment_1: S/N IS NOT STRICTLY RELEVANT. THIS IS comment_2: A SEARCH FOR WEAK EMISSION LINES comment_3: OR UPPER LIMITS TO THE H2 FLUX. ! linenum: 10.000 targname: HD115043 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 1.8S fluxnum_1: 1 fluxnum_2: 2 priority: 1 param_1: BRIGHT=RETURN, param_2: SEARCH-SIZE=3 req_1: CYCLE 4 / 10.0-10.3; req_2: ONBOARD ACQ FOR 10.1-10.3 comment_1: STEP-TIME=0.2 ! linenum: 10.100 targname: HD115043 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-A2 num_exp: 1 time_per_exp: 306.0S fluxnum_1: 1 fluxnum_2: 2 priority: 1 comment_1: STEP-TIME=3.0 ! linenum: 10.200 sequence_1: USE sequence_2: NTTS-H2A targname: HD115043 aperture: 2.0 num_exp: 10 req_1: GROUP 10.2-10.3 NO GAP comment_1: GROUP NO GAP IS REQUESTED BECAUSE comment_2: THESE STARS ARE VARIABLE. WE WOULD comment_3: LIKE TO OBTAIN ALL OBSERVATIONS AS comment_4: CLOSE TOGETHER IN TIME AS POSSIBLE. ! linenum: 10.300 sequence_1: USE sequence_2: NTTS-H2B targname: HD115043 aperture: 2.0 num_exp: 11 ! linenum: 12.000 sequence_1: USE sequence_2: NTTS-ACQ targname: BD+27D657 req_1: CYCLE 4 / 12.0-12.2; req_2: ONBOARD ACQ FOR 12.1-12.2 ! linenum: 12.100 sequence_1: USE sequence_2: NTTS-H2A targname: BD+27D657 aperture: 2.0 num_exp: 21 req_1: GROUP 12.1-12.2 NO GAP comment_1: GROUP NO GAP IS REQUESTED BECAUSE comment_2: THESE STARS ARE VARIABLE. WE WOULD comment_3: LIKE TO OBTAIN ALL OBSERVATIONS AS comment_4: CLOSE TOGETHER IN TIME AS POSSIBLE. ! linenum: 12.200 sequence_1: USE sequence_2: NTTS-H2B targname: BD+27D657 aperture: 2.0 num_exp: 22 ! linenum: 13.000 sequence_1: USE sequence_2: NTTS-ACQ targname: HD142361 req_1: CYCLE 4 / 13.0-13.2; req_2: ONBOARD ACQ FOR 13.1-13.2 ! linenum: 13.100 sequence_1: USE sequence_2: NTTS-H2A targname: HD142361 aperture: 2.0 num_exp: 19 req_1: GROUP 13.1-13.2 NO GAP comment_1: GROUP NO GAP IS REQUESTED BECAUSE comment_2: THESE STARS ARE VARIABLE. WE WOULD comment_3: LIKE TO OBTAIN ALL OBSERVATIONS AS comment_4: CLOSE TOGETHER IN TIME AS POSSIBLE. ! linenum: 13.200 sequence_1: USE sequence_2: NTTS-H2B targname: HD142361 aperture: 2.0 num_exp: 20 ! linenum: 14.000 sequence_1: USE sequence_2: NTTS-ACQ targname: BD+19D706 req_1: CYCLE 4 / 14.0-14.5; req_2: ONBOARD ACQ FOR 14.1-14.3 ! linenum: 14.100 sequence_1: USE sequence_2: NTTS-H2A targname: BD+19D706 aperture: 2.0 num_exp: 4 req_1: GROUP 14.1-14.2 NO GAP comment_1: GROUP NO GAP IS REQUESTED BECAUSE comment_2: THESE STARS ARE VARIABLE. WE WOULD comment_3: LIKE TO OBTAIN ALL OBSERVATIONS AS comment_4: CLOSE TOGETHER IN TIME AS POSSIBLE. ! linenum: 14.200 sequence_1: USE sequence_2: NTTS-H2B targname: BD+19D706 aperture: 2.0 num_exp: 5 ! linenum: 14.300 targname: BD+19D706 config: HRS opmode: ACQ/PEAKUP aperture: 0.25 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 50S priority: 1 param_1: SEARCH-SIZE=5 req_1: ONBOARD ACQ FOR 14.4-14.5 comment_1: STEP-TIME=2.0S ! linenum: 14.400 sequence_1: USE sequence_2: NTTS-H2A targname: BD+19D706 aperture: 0.25 num_exp: 6 req_1: GROUP 14.4-14.5 NO GAP comment_1: GROUP NO GAP IS REQUESTED BECAUSE comment_2: THESE STARS ARE VARIABLE. WE WOULD comment_3: LIKE TO OBTAIN ALL OBSERVATIONS AS comment_4: CLOSE TOGETHER IN TIME AS POSSIBLE. ! linenum: 14.500 sequence_1: USE sequence_2: NTTS-H2B targname: BD+19D706 aperture: 0.25 num_exp: 7 ! ! end of exposure logsheet ! No scan data records found