By studying the innermost, planet-forming regions of circumstellar disks around low-mass pre-main sequence stars we can refine theories of planet formation and develop timescales for the evolution of disks and their planets. Spitzer infrared observations of T Tauri stars have given us an unprecedented look at dust evolution in young objects, particularly the transitional disks. However, despite this ground breaking progress in studying the dust in young disks, the relationship between the dust and gas properties in the inner disk remains essentially unknown. Using STIS on HST, we propose to quantify the variability of H2 emission originating within the inner holes of transitional disks and explore its implications on dust distribution and planet formation.

There will be 3 visits for each of 3 targets (DM Tau, GM Aur and TW Hya). The visits will be separated by 1 week and 4 months. MAMA FUV and NUV observations will be done using the G140L and G230L gratings which cover 1150-1730 A and 1570-3180 A respectively for both DM Tau and GM Aur. The bright source, TW Hya, will use the E140M grating instead of the G140L grating to cover the FUV. Simultaneous optical and near-IR spectra will be taken using the CCD G430L grating (2900-5700 A) and the CCD G750L grating (5240-10270 A). We will also do fringe-flats to correct the spectra beyond 7000 A. We note that since this is a variability study we will need to use the STIS MAMA and the CCD in the same visit and since the CCD observations will take about 30 minutes, this visit structure is allowed according to the HST primer. We note that the only object of concern noticed by the BOT was one of our targets, TW Hya, in STIS/NUV-MAMA mode and we have taken this into consideration in our exposure times. Changes from Phase I: We have changed the apertures used in our fringe flats and ACCUM exposures to 0.3x0.09 and 52x2 respectively. We have removed peakups. We are now also using the LP filter for the ACQ of DM Tau and GM Aur. We are also setting timing requirements such that ground-based supporting observations will be possible. STAR FORMATION 12 false 0.0 0.0 false false false false false false SUPPORTED STAR PRE-MAIN SEQUENCE STAR PROTOPLANETARY DISK This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 11 01 51.9063 -34 42 17.02 J2000 STAR PRE-MAIN SEQUENCE STAR PROTOPLANETARY DISK This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 04 55 10.9800 +30 21 59.40 J2000 STAR PRE-MAIN SEQUENCE STAR PROTOPLANETARY DISK This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 04 33 48.7300 +18 10 10.00 J2000 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 STIS/FUV-MAMA Spectroscopic No No G140L 1425 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Spectroscopic No No G430L 4300 STIS/CCD Spectroscopic No No G750L 7751 Timing link suitability includes constraints ([02 After 01 by 6.0 to 8.0 days] [03 After 01 by 115.0 to 125.0 days]) The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. 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(Tic-Visit :proposal-id 11608 :visit-id "03" :proposal-version -1 :trans-version "20080624" :date "09-Jul-2008 09:33:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 339088 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11608 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11608 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2924 :al-overhead-at-end 0 :internal-dur-at-end 115 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11608 :visit-id "03" :orbit-number 2 :pcs-time 195 :si-vis-utilization 3062 :al-overhead-at-end 241 :internal-dur-at-end 321 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) true 2 0 Timing link suitability includes constraints ([05 After 04 by 6.0 to 8.0 days] [06 After 04 by 115.0 to 125.0 days]) The scheduling data was generated by CASM 17.2. 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CASM was run in Phase II mode. 1265247853000 327.7561381174854 (Tic-Visit :proposal-id 11608 :visit-id "08" :proposal-version -1 :trans-version "20080609" :date "01-Jul-2008 17:12:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 408640 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11608 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11608 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2950 :al-overhead-at-end 0 :internal-dur-at-end 115 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11608 :visit-id "08" :orbit-number 2 :pcs-time 195 :si-vis-utilization 3088 :al-overhead-at-end 81 :internal-dur-at-end 396 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) true 2 0 Timing link suitability includes constraints ([09 After 07 by 115.0 to 125.0 days]) The scheduling data was generated by CASM 17.2. 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