! Proposal 6495, submission 1 ! PI: Sidney Parsons ! Received Tue Feb 13 17:07:36 EST 1996 ! From: lhw@lowell.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6495,v 15.1 1997/02/21 16:08:28 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: Golombek ! Phone: 410-338-4974 , E-mail: golombek@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-0284.parsons.prop ! Date generated: Fri Dec 22 15:49:27 EST 1995 ! Proposal_Information ! Section 4 Title: The Mass of the Bright Giant HD 173764 Proposal_Category: GO Scientific_Category: COOL STARS Cycle: 6 Investigators PI_name: Sidney Parsons PI_Institution: Computer Sciences Corporation CoI_Name: Otto Franz CoI_Institution: Lowell Observatory Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) TRANS mode interferometry of HD 173764 at an estimated distance of 150 pc is expected to resolve the component separation of this G4 II + B9 spectroscopic binary system. With its 832 day period, the binary will be observable over a large range of orbital motion during the next two years. The FGS measurements, analyzed with respect to the spectroscopic orbit, will yield the system's inclination, distance, luminosities, and sum of the component masses. Concurrent POS mode astrometry will provide the mass ratio. Since G-type bright giants and supergiants are relatively rare, the primary's mass and luminosity are especially important for comparison with theory for rapid post main sequence evolution. Questions ! Free format text (please update) Observing_Description: We propose to make TRANS and POS mode observations at intervals of roughly 60 days for a total of 3 measurement sets before the target enters solar avoidance in November, plus 2 measurement sets in Spring 1997 if warranted by analysis of the 1996 observations. At the start of Cycle 6, the system is expected to be at a separation of about 34 mas, then progress toward smaller separations. The first 3 observations will provide a rough approximation to the inclination and major axis. If these early results are promising, we would submit a continuation proposal for Cycle 7 in order to secure measurements on the opposite side of the orbit for very definitive results. If we do resolve HD 173764 in TRANS mode over a substantial portion of the orbit AND observe it relative to a set of local reference stars, then we will, of course, get the mass ratio astrometrically. If we cannot resolve (or not resolve at all dates of observation) the components directly, then POS mode will still give us the reflex motion (i.e. astrometric perturbation) of the photocenter and thus the orbital inclination. With the inferred system parameters, the reflex motion of the primary around the center of mass is about 8 mas, significantly above the precision of 2 mas per observation. A combination of POS and TRANS modes, involving 3 - 4 reference stars, will fit into one orbit. The field of HD 173764 in the Guide Star Catalog finds several well distributed stars surrounding HD 173764 and available as local reference stars throughout the target visibility without the need for substantial off-nominal-roll requirements. TRANS-mode data will be reduced and analyzed with the use of algorithms and software developed, tested, and extensively applied at Lowell Observatory by Franz and Wasserman under GTO proposals of the Astrometry Science Team. TRANS scan data are analyzed under the assumption that the transfer function (TF) of a resolvable binary is a linear superposition of two single-star functions. If F(X) is the TF of a single star on the FGS X-axis, a double star will then yield a TF of the form D(X) = A*F(X + Z) + B*F(X + Z + S) + C, where A and B are the fractional intensities and S is the effective separation of the binary components along the FGS X-axis. Z and C are a zeropoint offset and a bias, respectively. An equivalent expression exists in Y. We determine the values of these parameters by least-squares solutions. Appropriate single-star transfer functions of high signal-to-noise ratio serve as templates. The resulting S-values in X and Y yield the binary separation and, by transformation from the FGS X-Y frame to equatorial coordinates, the position angle of the pair. The fractional intensities A and B yield directly the magnitude difference between the binary components. Tests on four visual binaries with very accurately known orbits have shown that FGS in TRANS mode yields both astrometric precision and accuracy of 1 mas from one observation. Derived magnitude differences are accurate to a few percent. Current estimation of the visual magnitude difference in this binary, from fitting UV and optical fluxes, is 3.3 +/- 0.3 mag. Assuming success, we will propose at a future time far-UV spectroscopy which should enable independent and probably more precise determination of the mass ratio via photospheric lines from the hot component. Mass ratio determination has been attempted from IUE mid-UV spectra, but the signature of photospheric lines could not clearly be found among G-star photospheric and wind features at limited S/N. There was a slight indication for a mass ratio of order 3.3 between cool primary and hot secondary, not consistent with present isochrone fitting which gives estimated masses of around 5 and 2.5 solar masses for cool and hot components. This study will provide important information on the accuracy of indirect methods for determining stellar parameters. Real_Time_Justification: Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: HD173764 Alternate_Names: BETA-SCT, HR7063 Description: STAR, G III-I, Composite Spectral Type Position: RA=18H 47M 10.40S +/- .1S, DEC=-04D 44' 51.6" +/- 1" !PLATE-ID=064F 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=4.22 +/- 0.03, ! Include at least V and B-V B-V=1.10 +/- 0.03, E(B-V)=0.20 +/- 0.04 Comments: Star 426 on OGF list Target_Number: 2 Target_Name: HD173764-2-REF Alternate_Names: GSC5122.00351 Description: CALIBRATION, ASTROMETRIC Position: RA=281.76945D +/- .0002D, DEC=-4.72450D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=13.01 +/- 0.2 ! Include at least V and B-V Comments: Star 180 on OGF list Target_Number: 3 Target_Name: HD173764-3-REF Alternate_Names: GSC5122.00462 Description: CALIBRATION, ASTROMETRIC Position: RA=281.86546D +/- .0002D, DEC=-4.74021D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=12.22 +/- 0.2 ! Include at least V and B-V Comments: Star 222 on OGF list Target_Number: 4 Target_Name: HD173764-4-REF Alternate_Names: GSC5122.00483 Description: CALIBRATION, ASTROMETRIC Position: RA=281.81180D +/- .0002D, DEC=-4.71856D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=13.12 +/- 0.2 ! Include at least V and B-V Comments: Star 233 on OGF list Target_Number: 5 Target_Name: HD173764-5-REF Alternate_Names: GSC5122.00747 Description: CALIBRATION, ASTROMETRIC Position: RA=281.74026D +/- .0002D, DEC=-4.73401D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=12.71 +/- 0.2 ! Include at least V and B-V Comments: Star 333 on OGF list Target_Number: 6 Target_Name: HD173764-6-REF Alternate_Names: GSC5122.00775 Description: CALIBRATION, ASTROMETRIC Position: RA=281.83711D +/- .0002D, DEC=-4.75820D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=12.48 +/- 0.2 ! Include at least V and B-V Comments: Star 348 on OGF list Target_Number: 7 Target_Name: HD173764-7-REF Alternate_Names: GSC5122.00813 Description: CALIBRATION, ASTROMETRIC Position: RA=281.75754D +/- .0002D, DEC=-4.74200D +/- .0002D ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! 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=11.58 +/- 0.2 ! Include at least V and B-V Comments: Star 367 on OGF list ! 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 ! DROP TO GYRO IF NECESSARY [NO REACQuisition] ORIENTation 83D TO 113D; ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! SCHEDulability ! AFTER [BY [TO ]] ! AFTER ! BEFORE BETWEEN 1-AUG-96 AND 15-AUG-96 ! GROUP WITHIN