! Proposal 6605, submission 1 ! PI: Joseph Patterson ! Received Tue Feb 13 09:50:43 EST 1996 ! From: aberman@stsci.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Alice Berman ! Phone: 410-338-4462 , E-mail: aberman@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! ! REVISION HISTORY: ! 13 Feb 1996 Carole Haswell email to Alice Berman for ! phase 2 deadline submission ! Issues Outstanding: ! (i) erroneous data rate diagnostic ! (ii) cut down # diodes to read ! 4 Jul 1996 Carole Haswell for implementation deadline ! Changes: SUBSTEP=2 ! READ-TIME=3.5 ! Time_Per_Exposure 14955.5S Proposal_Information ! Section 4 Title: Ultraviolet Pulsations in WZ Sagittae Proposal_Category: GO Scientific_Category: BINARIES AND STAR FORMATION Cycle: 6 Investigators PI_name: Joseph Patterson PI_Institution: Columbia University CoI_Name: Carole Haswell CoI_Institution: Columbia University Contact: Y ! Y or N (designate at most one contact) CoI_Name: Fu Hua Cheng CoI_Institution: University of Maryland Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) WZ Sagittae is one of the most famous and extensively studied cataclysmic variables. High-speed photometry at quiescence shows 28 s pulsations, whose origin is still unknown. Also puzzling is the high X-ray luminosity at quiescence; after photospheric light is subtracted, the star remains with L_x/L_opt~30, a surprisingly high ratio for any plausible accretion theory. An elegant solution to both problems would be achieved if the white dwarf is predominantly a `propellor' in quiescence, with the X-rays generated not in an accretion shock, but in the tangled, field-entrained plasma at the magnetospheric boundary. High-speed spectrophotometry in the UV can specify the origin of the pulsations by measuring the pulse fraction in continuum and lines, and can perhaps measure the photospheric magnetic field by `freezing' the Zeeman-split spectral features of the white dwarf as a function of rotational phase. Questions ! Free format text (please update) Observing_Description: We plan one visit to WZ Sge to perform high time resolution UV spectroscopy and simultaneous optical photometry using FOS with the G160L grating. This capability for simultaneous optical photometry and fast spectroscopy between 1140 - 2508 Angstrom is unique to FOS, and will be lost after cycle 6. While it is theoretically possible to obtain simultaneous optical photometric coverage from the ground, in practise weather and scheduling considerations often disrupt such plans. (The pulse amplitude varies by a factor of 2 on a timescale of hours, so simultaneity is needed.) The visibility window for WZ Sge is 52 minutes. We will operate in RAPID mode, with READ- TIME=6.18s, SUB-STEP=4. This gives us 4.51 spectra over the 27.9 s pulsation period. In `integral' photometry the amplitude is reduced by a factor sinc(PI fdt), so this will only diminish the measured amplitude by 7\%. WZ Sge has an orbital period of 82 minutes. Thus, in each HST visibility window we will obtain coverage of just over half the binary orbital phase. We require four consecutive HST visibility windows to cover all phases of WZ Sge's orbit. A fifth consecutive HST visibility window provides coverage of almost all binary phases three times. Therefore we request a total of 6 HST orbits: one for target acquisition, and five for our exposures. This gives us a total of 230 minutes of exposure, almost uniformly distributed in binary orbital phase. Hence we will discriminate between random variability and features which repeat each orbit. WZ Sge is slightly brighter than AE Aqr in the relevant UV continuum. Thus we studied the AE Aqr observation of Eracleous et al. (1994) to estimate detection limits. Over ~600 Angstrom of continuum we estimate that we can measure a pulse amplitude of 2\% with an `unbiased' search procedure (requirement of independent demonstration of periodicity), or ~1\% with the period assumed known. This meets every need of the science program. Real_Time_Justification: No special requirements. We have been observing the star for 19 years, so will certainly continue watching it with high-speed photometry at visual wavelengths. In 1996/7 we will emphasize multicolor observations, to extend the UV baseline to longer wavelengths (though without simultaneity of course). Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: WZ-SGE Alternate_Names: Description: STAR, INTERACTING BINARY, DWARF NOVA Position: RA=20H 7M 36.41S +/- 0.4", DEC=+17D 42' 15.4" +/- 0.4", PLATE-ID=02UQ Equinox: 2000 Flux: V=15.3 E(B-V)=0.0 +/- 0.05 B-V=0.0 +/- 0.2 U-B=-1.0 +/- 0.3 Comments: ECLIPSING BINARY, RAPID VARIABLE Copied above from GO6019 ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: PERIOD 0.0566878455D AND ZERO-PHASE JD2437547.72845 Exposure_Number: 1 Target_Name: WZ-SGE Config: FOS/BL Opmode: ACQ/BINARY Aperture: 4.3 Sp_Element: MIRROR Number_of_Iterations: 1 Time_Per_Exposure: 13.2S Special_Requirements: ONBOARD ACQ FOR 2; PHASE 0.15 TO 0.85 Comments: ACQ/BIN should be OK for this star (shallow eclipse). Computed the exposure time for ACQ/BIN using B-V and V, following table 2-5 in FOS manual. Assumes A1V spectral type. Checked with Tony Keyes. Exposure_Number: 2 Target_Name: WZ-SGE Config: FOS/BL Opmode: RAPID Aperture: 1.0-PAIR-A Sp_Element: G160L Optional_Parameters: READ-TIME=3.50 SUB-STEP=2 STEP-PATT=SINGLE Number_of_Iterations: 1 Time_Per_Exposure: 14955.5S Comments: Sub-Step = 2 for speed. Read-time =3.5 for 80% duty cycle 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 !Joe Patterson !Department of Astronomy !538 West 120th Street !New York, NY 10027 ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense Recipient_Email: ! Let us know what you think of this template and software! ! Please send a list of your likes and dislikes to your Program Coordinator