! 6471.prop - Revised 9 December, 1996 ! Revisions made at request of PI involve dropping of Period and Phase ! requirements in order to give it a second chance at being scheduled ! from the pool in the wake of the safing which caused the loss of the ! calendar on which it originally appeared. ! - Also combined all FOS science exposure time into one large exposure ! to be split automatically by the system as part of re-working to drop ! PERIOD and PHASE requirements. - RAL - 12/10/96 ! ! Proposal 6471, submission 1 ! PI: Simon Jeffery ! Received Wed Feb 14 05:59:13 EST 1996 ! From: csj@st-andrews.ac.uk ! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /net/ccp7/simon/observing/hst6471/6471.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Tue Feb 13 13:58:20 GMT 1996 Proposal_Information Title: A bolometric light curve for pulsating helium star LSS3184 Proposal_Category: GO Scientific_Category: HOT STARS Cycle: 6 Investigators PI_Name: Simon Jeffery PI_Institution: University of St. Andrews Abstract: LSS 3184 is an extreme helium star, that is, a `post-AGB' star with negligible hydrogen and significant overabundances of carbon, nitrogen and alpha-capture products in its atmosphere. In confirmation of a theoretical prediction, LSS 3184 was recently discovered to vary with a period of 2.5 hours, identical to that for the pulsating helium star V652 Her. Ground-based observations to verify the dicovery, define the visual (BVR) light curve and to establish the radial velocity curve were undertaken during May 1995. Ultraviolet observations are required to measure the bolometric light curve and the variation in Teff throughout the pulsation cycle. These will allow the stellar radius to be measured independent of distance. Only HST can provide the photometric precision necessary to make a direct test of stellar pulsation theory and an indirect test of modern opacities. These observations will also allow the first direct mass determination for a `bona fide' extreme helium star, vital for determining their evolutionary status. Questions Observing_Description: NOTE ( 9 December, 1996 ): The PERIOD and PHASE requirements in the original program have been dropped at the request of the PI in order to give the program a second chance at being pulled from the pool and scheduled in the wake of its loss with the calendar which was interrupted by the November 1996 FOS safing. The text below this is the old, original text. - RAL In order to determine the bolometric light curve for LSS 3184 it is necessary to obtain time-resolved UV spectrophotometry throughout the pulsation cycle (0.1066 days =153 minutes). Observations will be made with the FOS in RAPID mode, using grating G160L, reading out the spectrum every 20s. These spectra will be coadded into 100s and 100Angstrom bins to provide S/N>~100/(100Angstrom)/(100s) between 1200 and 2500Angstrom. The 20s readout will allow us to identify short duration events (eg shocks at minimum radius) and to fine-tune the binnning procedure. Good pointing accuracy (~0.04") is needed to ensure precise photometry so, because the target is bright, a four-stage peak up requiring one orbit will be used to acquire the target. Observations will then be carried out during three subsequent orbits. Allowing for guide star reacquisition and earth occultation, on target time will cover 88% of the pulsation cycle, with two phase gaps of 6% each and 6% redundancy. Real_Time_Justification: NOTE ( ( December, 1996 ): The PERIOD and PHASE requirements in the original program have been dropped at the request of the PI in order to give the program a second chance at being pulled from the pool and scheduled in the wake of its loss with the calendar which was interrupted by the November 1996 FOS safing. The text below this is the old, original text. - RAL Because the light curve coverage is not complete, it is necessary to schedule the observations carefully so that photometry is available for 0.05 cycles either side of predicted light maximum and minimum. This submission contains the best available optical ephemeris: Tmax = 2449477.46930 + 0.1066092 E +\- 0.0018 0.0000005 Further ground-based observations in May 1996 will double the existing ephemeris base-line and will be made available immediately they become available. UV light maximum and minimum are estimated to occur at optical phases 0.1 and 0.7 respectively (by analogy with V652 Her). To ensure coverage of the crucial phases, the first science exposure must start within ONE of the phase windows 0.00-0.03, 0.20-0.43, 0.58-0.65 or 0.80-1.00. Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: LSS3184 Alternate_Names: GSC0170-1207 Description: STAR,BP,PULSATING VARIABLE, Position: RA=14H 01M 36.62S +/- 0.03S,DEC=-66D 09' 55.8" +/- 0.5", PLATE-ID=060Y Equinox: J2000 RV_or_Z: V = -89 Flux: V = 12.56+/-0.013 B = 12.64+/-0.019 E(B-V) = 0.27+/-0.2 F(1275)=3.10+/-0.23e-13 F(1675)=2.08+/-0.19e-13 F(2400)=1.17+/-0.23e-13 Comments: Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: ! NOTE: The PERIOD and PHASE are commented out since the PI wants ! to drop these to give it a better chance at being scheduled ! a second time after the November 1996 FOS safing caused its ! original chance to be lost. - RAL 12/09/96 ! PERIOD 0.1066092D AND ZERO-PHASE JD2449477.469300 On_Hold_Comments: Visit_Comments: ! NOTE: The Visit_Comments are commented out below since ephemeris is ! being disregarded in this revised version which the PI desires ! to use in the wake of the November 1996 FOS safing. - RAL 12/09/96 ! Visit_Comments: Refer to PI for most recent ephemeris Exposure_Number: 10 Target_Name: LSS3184 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 4.3 Sp_Element: G160L Wavelength: 1100-2500 Optional_Parameters: SCAN-STEP-Y=1.23,SEARCH-SIZE-Y=3,SEARCH-SIZE-X=1 Number_of_Iterations: 1 Time_Per_Exposure: 1.5S Special_Requirements: ONBOARD ACQ FOR 20 Comments: FOS Handbook Table 2-1 Pattern A Wavelength range used to avoid wrap-around problem in zeroth order spike during ACQ/PEAK as per Keyes. Exposure_Number: 20 Target_Name: LSS3184 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 1.0-PAIR-A Sp_Element: G160L Wavelength: 1100-2500 Optional_Parameters: SCAN-STEP-Y=0.61,SCAN-STEP-X=0.61,SEARCH-SIZE-Y=2,SEARCH-SIZE-X=6 Number_of_Iterations: 1 Time_Per_Exposure: 1.5S Special_Requirements: ONBOARD ACQ FOR 30 Comments: FOS Handbook Table 2-1 Pattern B2 Uses STEP-PATT=SINGLE by default. Wavelength range used to avoid wrap-around problem in zeroth order spike during ACQ/PEAK as per Keyes. Exposure_Number: 30 Target_Name: LSS3184 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.5-PAIR-A Sp_Element: G160L Wavelength: 1100-2500 Optional_Parameters: SCAN-STEP-Y=0.29,SCAN-STEP-X=0.29,SEARCH-SIZE-Y=3,SEARCH-SIZE-X=3 Number_of_Iterations: 1 Time_Per_Exposure: 1.5S Special_Requirements: ONBOARD ACQ FOR 40 Comments: FOS Handbook Table 2-1 Pattern C2 Uses STEP-PATT=SINGLE by default. Wavelength range used to avoid wrap-around problem in zeroth order spike during ACQ/PEAK as per Keyes. Exposure_Number: 40 Target_Name: LSS3184 Config: FOS/BL Opmode: ACQ/PEAK Aperture: 0.25-PAIR-A Sp_Element: G160L Wavelength: 1100-2500 Optional_Parameters: SCAN-STEP-Y=0.11,SCAN-STEP-X=0.11,SEARCH-SIZE-Y=4,SEARCH-SIZE-X=4 Number_of_Iterations: 1 Time_Per_Exposure: 13S Special_Requirements: ONBOARD ACQ FOR 50 Comments: FOS Handbook Table 2-1 Pattern P4 Uses STEP-PATT=SINGLE by default. Wavelength range used to avoid wrap-around problem in zeroth order spike during ACQ/PEAK as per Keyes. Exposure time dropped slightly in 4th stage as per Keyes in order to make all 4 stages fit in first orbit in current system. Exposure_Number: 50 Target_Name: LSS3184 Config: FOS/BL Opmode: RAPID Aperture: 1.0-PAIR-A Sp_Element: G160L Wavelength: Optional_Parameters: STEP-PATT=SINGLE,READ-TIME=20 Number_of_Iterations: 1 Time_Per_Exposure: 8540S ! Commenting out the original exposure value here in favor of the combined ! total for all the science exposures to be split automatically by the system ! in the most advantageous way. Exp Log lines 60 and 70 are also consequently ! dropped out as well. - RAL - 12/10/96 ! Time_Per_Exposure: 2660S Special_Requirements: Comments: ! NOTE: The PHASEs listed below are commented out since the PI wants ! to drop these to give it a better chance at being scheduled ! a second time after the November 1996 FOS safing caused its ! original chance to be lost. - RAL 12/09/96 ! ! PHASE 0.20 TO 0.43 ! Comments: Also permit ! PHASE 0.80 TO 1.00 or ! PHASE 0.58 TO 0.65 or ! PHASE 0.00 TO 0.03 ! ! Exposure_Number: 60 ! Target_Name: LSS3184 ! Config: FOS/BL ! Opmode: RAPID ! Aperture: 1.0-PAIR-A ! Sp_Element: G160L ! Wavelength: ! Optional_Parameters: STEP-PATT=SINGLE,READ-TIME=20 !Number_of_Iterations: 1 ! Time_Per_Exposure: 49M !Special_Requirements: NO SPLIT ! Comments: ! ! Exposure_Number: 70 ! Target_Name: LSS3184 ! Config: FOS/BL ! Opmode: RAPID ! Aperture: 1.0-PAIR-A ! Sp_Element: G160L ! Wavelength: ! Optional_Parameters: STEP-PATT=SINGLE,READ-TIME=20 !Number_of_Iterations: 1 ! Time_Per_Exposure: 49M !Special_Requirements: ! Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address Ship_Via: 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