! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6421,v 4.1 1996/03/08 14:22:52 pepsa Exp $ ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6421,v 4.1 1996/03/08 14:22:52 pepsa Exp $ ! ! 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: Landis ! Phone: 410-338-4560 , E-mail: landis@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-0070.schmidt.prop ! Date generated: Fri Dec 22 15:52:09 EST 1995 ! Proposal_Information ! Section 4 Title: Resolving the Unique Magnetic/Non- Magnetic Double-Degenerate Binary LB 11146 Proposal_Category: GO Scientific_Category: BINARIES AND STAR FORMATION Cycle: 6 Investigators PI_name: Gary Schmidt PI_Institution: University of Arizona CoI_Name: James Liebert CoI_Institution: University of Arizona Contact: ! Y or N (designate at most one contact) CoI_Name: Paul Smith CoI_Institution: University of Arizona Contact: Y ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) LB 11146 is an unresolved binary of unknown period consisting of a nonmagnetic (B_e < 30 kG) white dwarf plus a component with one of the strongest magnetic fields yet found on a white dwarf (B_e ~ 700 MG). The magnetic star also possesses a different atmospheric composition than its hydrogen-dominated companion, as it exhibits several broad spectral features that cannot be attributed to hydrogen in the presence of a strong magnetic field. Finally, the binary is the only known double- degenerate system where the total mass exceeds the Chandrasekhar limit. Knowledge of the current component separation is critical for understanding whether the peculiar end-state of this binary is a result of differences in the star-formation process or of a peculiar mass-transfer or common-envelope effect. Radial velocity studies appear to preclude short periods (a \lta 0.1 AU), while ground-based images are unresolved at the limit of ~20 AU. We propose to investigate the important region 2-20 AU ("s0.05-"s0.5) through FOC imaging. Frames obtained at two different wavelengths and covering just one HST orbit will distinguish between the two components and at the same time test a model of LB 11146 based on a spectroscopic decomposition of the binary. Questions ! Free format text (please update) Observing_Description: Simulations based on the known combined spectral flux of the two components and of the point-spread function of HST+FOC have demonstrated that the goals of this project can be reached with just two FOC/96 (512*512) images; one a 1200 s exposure using the F307M+F6ND filters; the other of 600 s duration using F550M+F2ND. These filter combinations ensure that the count rate will be linear even if the binary is not resolved. The exposure time has been set so that a signal-to- noise-ratio of at least 40 is reached for each component assuming the fluxes derived in the Liebert et al. (1993) model. ``FOCSIM'' calculations estimate ~340 counts in the central pixel for each star in the F550M+F2ND observation. For F307M+F6ND in 1200 s, we expect ~180 cts and ~360 cts in the central pixel for the nonmagnetic and magnetic components, respectively. In both exposures the background is <=sssim1 count. The target will be acquired using the ``Blind Pointing'' procedure (Mode III target acquisition). The images will only require 1 orbit to acquire. No special calibrations will be needed. begintabularlll Cycle 6 & Primary Orbits:1 & Exposures:2, endtabular Real_Time_Justification: None. None. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: LB11146 Alternate_Names: PG0945+246 Description: STAR, Composite Spectral Type Position: ! Most common specification format is RA=09H 48M 46.74S +/- 1.0", ! RA=0H 0M 0.00S +/- 0S, DEC=24D 21' 27.46" +/- 1.0", ! DEC=0D 0' 0.0" +/- 0", PLATE-ID=01X3 ! PLATE-ID=0000 Equinox: J2000 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: V=14.4 +/- 0.1, B-V=-0.15 ! Include at least V and B-V Comments: ! 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: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! DROP TO GYRO IF NECESSARY [NO REACQuisition] ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! SCHEDulability ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN