Proposal_Information ! Section 4 Title: Decoding the Inner Disk about Beta- Pictoris Proposal_Category: GO Scientific_Category: BINARIES AND STAR FORMATION Cycle: 6 Investigators PI_name: Alfred Schultz PI_Institution: Computer Sciences Corporation CoI_Name: Fred Bruhweiler CoI_Institution: Catholic University of America Contact: ! Y or N (designate at most one contact) CoI_Name: Kwang-Ping Cheng CoI_Institution: California State University Fullerton Contact: ! Y or N (designate at most one contact) CoI_Name: Michael DiSanti CoI_Institution: Catholic University of America Contact: ! Y or N (designate at most one contact) CoI_Name: Forrest Hamilton CoI_Institution: Computer Sciences Corporation Contact: ! Y or N (designate at most one contact) CoI_Name: Dorothy Fraquelli CoI_Institution: Computer Sciences Corporation Contact: ! Y or N (designate at most one contact) CoI_Name: Helen Hart CoI_Institution: Computer Sciences Corporation Contact: ! Y or N (designate at most one contact) CoI_Name: Charles ``Tony'' Keyes CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Kent Reinhard CoI_Institution: Doane College, Crete Contact: ! Y or N (designate at most one contact) CoI_Name: Daryl Swade CoI_Institution: Computer Sciences Corporation Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) The FOS will be used to study the UV emission line characteristics of the inner disk about Beta Pictoris at a distance of 1.3" from the star. Our goal is to investigate the proposed infall and subsequent sublimation of comet-like bodies into beta Pictoris and to study the composition of inner disk material. Due to the favorable edge-on orientation of the disk, the gaseous component of the disk has been detected in absorption. The inner disk gases are excited, dissociated, and ionized by stellar photons. The detection of emissions from the gaseous disk in the vicinity of the star, possibly cometary in nature (eg., CS 2576 Angstrom, OH 3064 Angstrom), would unequivocally establish the sublimation of comet-like bodies or possibly volatiles from grains within the circumstellar disk. Our ultimate goal is to ascertain the composition of the inner disk. The GHRS will be employed to acquire the bright targets (alpha and beta Pictoris) followed by slewing the telescope to position the targets into the FOS aperture. The core of the PSF will be positioned behind the space separating the FOS 0.5-PAIR apertures. Spectra using the G190H and G270H gratings, spectral interval 1573 - 3301 Angstrom, will be obtained of both sides of the disk. Cycle 6 is the last opportunity to assess the spectral characteristics of the inner disk material in this wavelength region. Questions ! Free format text (please update) Observing_Description: FOS spectra with the the 0.4'' paired apertures (0.5-PAIR) using the G190H and G270H gratings will be obtained of alpha and beta Pictoris. Each aperture will be at a distance of ~1.3'' from the bright stars. The bright stars will be acquired with the GHRS and the telescope slewed to position alpha and beta Pic into the FOS blue aperture. The FOS shutter will be closed during the slew. The stellar PSF for each target star will be positioned between the paired apertures, isolating the core of the PSF from the FOS detector. A total of two FOS ``RAPID'' mode observations (one for each grating) of each star will be obtained. The paired aperture will allow separate spectra for each side of the disk to be obtained. The observations need to be repeated for alpha Pic. The alpha Pic observations will be scaled and subtracted from the Beta Pic observations. We expect the alpha Pic observations to contain mostly slight scatter and light from the diffraction spikes. The remaining time during the first orbit after the acquisition will be used to obtain spectra. We estimate a total of ~3600 seconds of integration time will be available for each grating. This observing strategy will generate quite a few spectra. Depending upon the RAPID mode READ-TIME, a minimum of ~96 spectra (READ-TIME=74 seconds), or up to ~1100 spectra (READ-TIME=6.4 seconds) will be obtained for each bright star. The READ-TIME exposure is split between the two apertures. A read time of 74 seconds will yield a 37 second exposure in each aperture. We model the FOS disk exposures by first, assuming the surface brightness of the circumstellar disk is ~16.0 mag/sq. arcsecond as reported by Paresce and Burrows (1987), and second, the disk flux is mostly reflected light from beta Pic, a A5-type star. Using a 16 magnitude A5-star, a 1000 second exposure will yield 100 counts (S/N ~10) for each side of the disk with the G190H grating, and 300 counts (S/N ~17) with the G270H grating. In practice, the exposure lengths will be increased to fill the orbit. Light scatter within the telescope will be a problem. We are unsure at this time the magnitude of the scatter, and will employ FOS ``RAPID'' mode to decrease the effects of overexposure and wrap around in the spectra. Each visit to a target star will follow a 3-orbit sequence. First Orbit: 7.5 minutes for guide star acquisition GHRS LSA acquisition slewing to the FOS blue aperture start FOS ``RAPID'' mode observation (G190H) 0.5-PAIR aperture Second Orbit: 6 minutes for guide star reacquisition complete G190H ``RAPID'' observation start FOS ``RAPID'' mode observation (G270H) 0.5-PAIR aperture Third Orbit: 6 minutes for guide star reacquisition complete G270H ``RAPID'' observation Real_Time_Justification: Two requirements are necessary to spectroscopically observe the inner disk: 1) GHRS acquisition of the targets and positioning of the bright stars at the center of the FOS large science aperture, and 2) the orientation (ORIENT) to be used should be +30 degrees, or +210 degrees. A GHRS acquisition is required to acquire the targets and correctly position the core of the stellar PSFs in the FOS blue aperture. The FOS aperture wheel will be prepositioned to the 0.4" paired aperture position. Positioning in the FOS aperture is critical so as not to cause overexposure effects in the FOS diodes. The orientation (ORIENT) should be such that the dust disk appears in opposing FOS 0.4" apertures with the central star behind the space between the two apertures. From discussions with two STScI scientists, using the GHRS to acquire a bright star and slewing to the FOS aperture has been tested and was successful. It should be possible to position Alpha & Beta Pic in the center of the FOS aperture. We want to position the bright targets in the center of the large aperture and NOT in one of the small 0.4" paired apertures. The accuracy of the pointing after slewing from the HRS to the center of the 4.3 aperture of the FOS/Blue is ~0.2". There should not be a problem with centering a star between the 0.5-PAIR apertures with the star occulted. FOS spectra (G190H & G270GH) will be obtained of stars SS2-213 (A5) & SS2-201 (A7), to be used as calibration targets. Spectral features of the disk need to be identified from those of beta Pic (type-A5). In addition, we expect during the reduction of the disk spectra to subtract the spectra obtained of alpha Pic (type-A7). This step may introduce false absorption features. We estmate a 1000 second exposure with the G190H & G270H gratings will yield ~400 cts. at 2300 Angstrom\ and ~1500 cts. at 3100 Angstrom\ for SS2-213 (A5), and ~400 cts. at 2300 Angstrom\ and ~2000 cts at 3100 Angstrom\ for SS2-201 (A7). These count rates are for quarter-step pixel. The S/N will range from ~20 to ~40. Each visit to a Calibration star will follow a 2-orbit sequence. First Orbit: 7.5 minutes for guide star acquisition FOS ACQ/BINARY acquisition 4.3" aperture (2.1 sec) FOS ACQ/PEAK 5x5 search upper 0.25-PAIR aperture (2.0 sec/dwell point) FOS ACQ/PEAK 5x5 search upper 0.25-PAIR aperture (2.0 sec/dwell point) total overhead 43 minutes Second Orbit: 6 minutes for guide star reacquisition 1000 second ACCUM G190H upper 0.5-PAIR aperture 1000 second ACCUM G270H upper 0.5-PAIR aperture 10 minutes of overhead Cycle 6 Calibration Orbits: 4 Exposures: 4 Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: !****************************************************************************** Fixed_Targets Target_Number: 1 Target_Name: HD39060 Alternate_Names: BETA-PICTORIS Description: STAR,A4-A9 III-I,PROTOPLANETARY DISK Position: RA=5H 47M 17.1S +/- 0.01S, DEC=-51D 03' 59.4" +/- 0.1" Equinox: J2000.0 RV_or_Z: V=+20 RA_PM: 0.001273 ! Units are seconds of time per year Dec_PM: 0.079 ! Units are seconds of arc per year Epoch: J2000.0 Annual_Parallax: 0.055 Flux: SURF(V)=16.3 SURF(B)=16.6 SURF(R)=15.9 SURF(I)=15.9 Comments: Beta Pic proper motion, parallax, V-magnitude=3.85, color index B-V=0.171, spectral type=A5III, and radial velocity obtained from The Hipparcos Input catalogue, EAS SP-1136, 1992. Surface brightness/sq. arcsecond for the circumstellar disk obtained from Paresce and Burrows 1989, Ap.J., 319, L23-L25. !****************************************************************************** Target_Number: 2 Target_Name: HD50241 Alternate_Names: ALPHA-PICTORIS Description: STAR,A4-A9 V-IV Position: RA=6H 48M 11.437S +/- 0.01S, DEC=-61D 56' 28.95" +/- 0.1" Equinox: J2000.0 RV_or_Z: V=+20.6 RA_PM: -0.007319 ! Units are seconds of time per year Dec_PM: 0.269 ! Units are seconds of arc per year Epoch: J2000.0 Annual_Parallax: 0.046 Flux: V=3.266+/-0.05 TYPE=A7IV B-V=0.225+/-0.19 Comments: Alpha Pic proper motion, parallax, V-magnitude=3.266, color index B-V=0.225, spectral type=A7IV, and radial velocity obtained from The Hipparcos Input catalogue, EAS SP-1136, 1992. !****************************************************************************** Target_Number: 3 Target_Name: SS2-201 Alternate_Names: Description: STAR Position: RA=12H 44M 20.45S +/- 0.01S, DEC=33D 36' 12.59" +/- 0.1", PLATE-ID=01PQ ! from Al's 02/03/95 mail. Equinox: J2000.0 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: 1983.13305 ! from Al's 02/03/95 mail. Annual_Parallax: Flux: B=12.5+/-0.05 ! From SIMBAD search TYPE=A7IV Comments: SS2-201 blue magnitude and spectral type obtained from Sanduleak, N. 1988, Ap.J.Suppl.Ser., 66, 309. Blue magnitude is an eye estimate of the image density combined with image diameters on POSS O-prints. !****************************************************************************** Target_Number: 4 Target_Name: SS2-213 Alternate_Names: Description: STAR Position: RA=12H 48M 55.81S +/- 0.01S, DEC=33D 19' 34.72" +/- 0.1", PLATE-ID=01PQ ! from Al's 02/03/95 mail. Equinox: J2000.0 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: 1983.13305 ! from Al's 02/03/95 mail. Annual_Parallax: Flux: B=13.0+/-0.05 ! From SIMBAD search TYPE=A5IV Comments: SS2-213 blue magnitude and spectral type obtained from Sanduleak, N. 1988, Ap.J.Suppl.Ser., 66, 309. Blue magnitude is an eye estimate of the image density combined with image diameters on POSS O-prints. !****************************************************************************** Visits Visit_Number: 1 Visit_Requirements: PCS MODE Fine ORIENT 208D TO 228D ! or ORIENT 28D TO 48D schedules in Late Dec 96 - Jan. 97 GROUP 1-2 WITHIN 30D On_Hold_Comments: Visit_Comments: Offset angle used for the ORIENT calculation was 8.2 degreees as defined for the FOS/BL paired apertures. The disk is aligned NNE to SSW (30 deg. and 210 deg.). An of 208D to 228D is also an exceptable range for ORIENT. Exposure_Number: 1 Target_Name: HD39060 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 4.3 Sp_Element: G130H Optional_Parameters: SCAN-STEP-Y=1.23 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=1 Number_of_Iterations: 1 Time_Per_Exposure: 3S Special_Requirements: ONBOARD ACQ FOR 2 Comments: Stage 1 of 4 stage peakup Exposure_Number: 2 Target_Name: HD39060 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 1.0-PAIR-A Sp_Element: G130H Optional_Parameters: SCAN-STEP-Y=0.602 SCAN-STEP-X=0.602 SEARCH-SIZE-Y=2 SEARCH-SIZE-X=6 Number_of_Iterations: 1 Time_Per_Exposure: 3S Special_Requirements: ONBOARD ACQ FOR 3 Comments: Stage 2 of 4 stage peakup. Exposure_Number: 3 Target_Name: HD39060 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: SCAN-STEP-Y=0.3 SCAN-STEP-X=0.3 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 Number_of_Iterations: 1 Time_Per_Exposure: 1S Special_Requirements: ONBOARD ACQ FOR 4 Comments: Stage 3 of 4 stage peakup. Exposure_Number: 4 Target_Name: HD39060 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: G190H Optional_Parameters: SCAN-STEP-Y=0.172 SCAN-STEP-X=0.172 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 Number_of_Iterations: 1 Time_Per_Exposure: 1S Special_Requirements: ONBOARD ACQ FOR 5-6 Comments: Stage 4 of 4 stage peakup. Exposure_Number: 5 Target_Name: HD39060 Config: FOS/BL Opmode: RAPID Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: READ-TIME=60.0 SUB-STEP=4 STEP-PATT=OBJ-OBJ Number_of_Iterations: 1 Time_Per_Exposure: 2880S Special_Requirements: POS TARG 0.0078,-1.3075 Comments: Spectra will be read from each aperture. The exposure will be split into 30sec of integration time in each aperture. POS TARG to position star between apertures. Exposure_Number: 6 Target_Name: HD39060 Config: FOS/BL Opmode: RAPID Aperture: 0.5-PAIR-A Sp_Element: G270H Optional_Parameters: READ-TIME=60.0 SUB-STEP=4 STEP-PATT=OBJ-OBJ Number_of_Iterations: 1 Time_Per_Exposure: 2880S Special_Requirements: SAME POS AS 5 Comments: Spectra will be read from each aperture. The exposure will be split into 30sec of integration time in each aperture. !****************************************************************************** Visit_Number: 2 Visit_Requirements: PCS MODE Fine On_Hold_Comments: Visit_Comments: We wish to have this visit scheduled close in time to visit one since we plan to subtact the Alpha-Pic spectra from the Beta-Pic one. In doing so we would like to keep the light path through HST to be as identical as possible for visits 1 & 2. Exposure_Number: 1 Target_Name: HD50241 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 4.3 Sp_Element: G130H Optional_Parameters: SCAN-STEP-Y=1.23 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=1 Number_of_Iterations: 1 Time_Per_Exposure: 3S Special_Requirements: ONBOARD ACQ FOR 2 Comments: Stage 1 of 4 stage peakup Exposure_Number: 2 Target_Name: HD50241 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 1.0-PAIR-A Sp_Element: G130H Optional_Parameters: SCAN-STEP-Y=0.602 SCAN-STEP-X=0.602 SEARCH-SIZE-Y=2 SEARCH-SIZE-X=6 Number_of_Iterations: 1 Time_Per_Exposure: 3S Special_Requirements: ONBOARD ACQ FOR 3 Comments: Stage 2 of 4 stage peakup. Exposure_Number: 3 Target_Name: HD50241 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: SCAN-STEP-Y=0.3 SCAN-STEP-X=0.3 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 Number_of_Iterations: 1 Time_Per_Exposure: 1S Special_Requirements: ONBOARD ACQ FOR 4 Comments: Stage 3 of 4 stage peakup. Exposure_Number: 4 Target_Name: HD50241 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: G190H Optional_Parameters: SCAN-STEP-Y=0.172 SCAN-STEP-X=0.172 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3 Number_of_Iterations: 1 Time_Per_Exposure: 1S Special_Requirements: ONBOARD ACQ FOR 5-6 Comments: Stage 4 of 4 stage peakup. Exposure_Number: 5 Target_Name: HD50241 Config: FOS/BL Opmode: RAPID Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: READ-TIME=60.0 SUB-STEP=4 STEP-PATT=OBJ-OBJ Number_of_Iterations: 1 Time_Per_Exposure: 2880S Special_Requirements: POS TARG 0.0078,-1.3075 Comments: Spectra will be read from each aperture. The exposure will be split into 30sec of integration time in each aperture. POS TARG to position star between apertures. Exposure_Number: 6 Target_Name: HD50241 Config: FOS/BL Opmode: RAPID Aperture: 0.5-PAIR-A Sp_Element: G270H Optional_Parameters: READ-TIME=60.0 SUB-STEP=4 STEP-PATT=OBJ-OBJ Number_of_Iterations: 1 Time_Per_Exposure: 2880S Special_Requirements: SAME POS AS 5 Comments: Spectra will be read from each aperture. The exposure will be split into 30sec of integration time in each aperture. !****************************************************************************** Visit_Number: 3 Visit_Requirements: PCS MODE Fine On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: SS2-201 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Number_of_Iterations: 1 Time_Per_Exposure: 1.75S Special_Requirements: ONBOARD ACQ FOR 2 Comments: A normal BINARY. Exposure_Number: 2 Target_Name: SS2-201 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: MIRROR Optional_Parameters: SCAN-STEP-X=0.17, SCAN-STEP-Y=0.17, SEARCH-SIZE-X=5, SEARCH-SIZE-Y=5, TYPE=UP Number_of_Iterations: 1 Time_Per_Exposure: 2.0S Special_Requirements: ONBOARD ACQ FOR 3 Exposure_Number: 3 Target_Name: SS2-201 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: MIRROR Optional_Parameters: SCAN-STEP-X=0.052, SCAN-STEP-Y=0.052, SEARCH-SIZE-X=5, SEARCH-SIZE-Y=5, TYPE=UP Number_of_Iterations: 1 Time_Per_Exposure: 2.0S Special_Requirements: ONBOARD ACQ FOR 4-5 Exposure_Number: 4 Target_Name: SS2-201 Config: FOS/BL Opmode: ACCUM Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: Comments: Spectra will be read from the upper aperture. Exposure_Number: 5 Target_Name: SS2-201 Config: FOS/BL Opmode: ACCUM Aperture: 0.5-PAIR-A Sp_Element: G270H Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: Comments: Spectra will be read from the upper aperture. !****************************************************************************** Visit_Number: 4 Visit_Requirements: PCS MODE Fine On_Hold_Comments: Visit_Comments: Exposure_Number: 1 Target_Name: SS2-213 Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Number_of_Iterations: 1 Time_Per_Exposure: 2.54S Special_Requirements: ONBOARD ACQ FOR 2 Comments: A normal BINARY. Exposure_Number: 2 Target_Name: SS2-213 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: MIRROR Optional_Parameters: SCAN-STEP-X=0.17, SCAN-STEP-Y=0.17, SEARCH-SIZE-X=5, SEARCH-SIZE-Y=5, TYPE=UP Number_of_Iterations: 1 Time_Per_Exposure: 2.0S Special_Requirements: ONBOARD ACQ FOR 3-4 Exposure_Number: 3 Target_Name: SS2-213 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: MIRROR Optional_Parameters: SCAN-STEP-X=0.052, SCAN-STEP-Y=0.052, SEARCH-SIZE-X=5, SEARCH-SIZE-Y=5, TYPE=UP Number_of_Iterations: 1 Time_Per_Exposure: 2.0S Special_Requirements: ONBOARD ACQ FOR 4-5 Exposure_Number: 4 Target_Name: SS2-213 Config: FOS/BL Opmode: ACCUM Aperture: 0.5-PAIR-A Sp_Element: G190H Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: Comments: Spectra will be read from the upper aperture. Exposure_Number: 5 Target_Name: SS2-213 Config: FOS/BL Opmode: ACCUM Aperture: 0.5-PAIR-A Sp_Element: G270H Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 900S Special_Requirements: Comments: Spectra will be read from the upper aperture. !****************************************************************************** Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! ! Space Telescope Science Institu ! te ! 3700 San Martin Drive ! Baltimore ! 21218 ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense Recipient_Email: ! Needed if Ship_To: is not PI_Address !