! 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:
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