! Proposal 6641, submission 1 ! PI: Laurence G. Taff ! Received Mon Feb 5 12:26:34 EST 1996 ! From: hershey@stsci.edu ! ! CYCLE 6 PROP 6641 ! ! >>>> THIS IS A COPY OF CY 5 PROP WITH CHANGES TO YEAR & CYCLE NUMBER ! v---BUT WILL USE FOR CY6 ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 6641,v 5.1 1996/11/22 18:14:52 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: Denise Taylor ! Phone: 410 338-4824 , E-mail: dctaylor@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sun Dec 18 11:55:37 EST 1994 ! Proposal_Information ! Section 4 Title: Continuation of Mass Ratio Determination for Doubles with Substellar Mass Members Proposal_Category: GO Scientific_Category: Cool Stars Cycle: 6 Investigators PI_name: Laurence G. Taff PI_Institution: Space Telescope Science Institute CoI_Name: John Hershey CoI_Institution: Computer Sciences Corp (at Space Telescope Science Institute) Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) Stellar masses which lie at or just below the stellar/sub- stellar boundary are difficult to determine with certainty. Only binary stars with low luminosity members provide these low masses. In the best studied cases a significant source of uncertainty in the estimated masses is the blending of the light on the photographic plates used to record the stars' positions. The blending must be modeled in order to determine the locus of the center of mass. The position of the center of mass determines the mass ratio. Without knowing this, or the fraction of the total mass of the pair present in each component of the system, the uncertainty resulting from blending provides a point of attack for those who question the reality of mass measurements as low as 0.06 Msun , and thus not clearly sub-stellar or ``brown dwarfs''. We have observed the separation of L722-22 in Cycle 3 and 4 of this proposal with sub-milliarcsecond internal precision, far below the error level of ground-based infrared speckle measurements. In a few years the relative orbit could be determined with milliarcsecond-level precision and the center of mass will be located for determination of the individual mass of each component. This is the third year of our original proposal. Questions ! Free format text (please update) Observing_Description: We plan to continue as in Cycle 3 and 4, taking FGS TRANS mode scans of the double and POS mode observations of ? reference stars, with 3 visits of two orbits in a cycle. A ? POS mode observation of the double and a TRANS mode ? observation of a reference star will provide a check on the ? stability of the TRANS-POS mode offset for center-of-mass ? determination. All observations need to be done in fine-lock guidance. Real_Time_Justification: ? No special scheduling requirements except the roughly even ? spacing of the 3 visits in the observing year. ? None. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: L722-22 Alternate_Names: LHS 1047 Description: star, M V-IV Position: RA= 3.8640416D +/-0.00139D, DEC=-16.1307D +/-0.00139D Equinox: 2000 ! RV_or_Z: RA_PM: 0.04550 ! Units are seconds of time per year Dec_PM: -0.5950 ! Units are seconds of arc per year Epoch: 1983.8 Annual_Parallax: 0.1890 Flux: V=12.62 +/- 0.5 ! Include at least V and B-V Comments: SCIENTIFIC TARGET Target_Number: 2 Target_Name: L722-22-0002-REF Description: star Position: RA= 3.8676667D +/-0.00139D, DEC=-16.1415272D +/-0.00139D Equinox: 2000 ! RV_or_Z: Epoch: 1983.8 Flux: V=14.82 +/- 0.5 ! Include at least V and B-V Comments: CLOSE REF STAR Target_Number: 3 Target_Name: L722-22-0003-REF Description: star Position: RA= 3.8372500D +/-0.00139D, DEC=-16.1202507D +/-0.00139D Equinox: 2000 Epoch: 1983.8 Flux: V=14.10 +/- 0.5 ! Include at least V and B-V Comments: CLOSE REF STAR ! 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 ! GUIDing TOLerance 0.005" ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER 1-JUN-95 ! BEFORE 1-JUL-95 BETWEEN 16-JUN-96 AND 07-JUL-96 ! GROUP WITHIN