0 Assigned ID: 634 ----- Attempting Submission 1 (Fri Apr 08 17:51:26 GMT 2016) ----- HST Phase I Proposal 634 (v652her_phase1.apt) successfully submitted. Receipt: # 634-1 ----- Attempting Submission 2 (Fri Apr 08 18:00:47 GMT 2016) ----- Resubmission with WAVECAL=NO Included TARGET=WAVE at start of each visit and at end of each orbit. Configuration for WAVECAL the same as for Science. Exposure time set to 20s. 480461668 ----- Attempting Submission 3 (Wed Nov 30 11:18:20 GMT 2016) ----- Ulraviolet fluxes and dynamical structure in the pulsating atmosphere of helium star V652 Her V652 Her is a B-type extreme helium star which pulsates with a period of 154 minutes and a velocity amplitude of 70 km/s. It is believed to have formed from the merger of two helium white dwarfs, and to be the progenitor of a helium-rich hot subdwarf. Its remarkable velocity curve consists of a short shocked acceleration followed by near-ballistic deceleration. Optical spectroscopy has recently resolved dynamical structure within the pulsating photosphere. In contrast, the radius and mass of V652 Her have been measured with a precision seriously limited by sparse low-resolution IUE photometry. To measure the mass to better than +/- 0.1 Msun, constrain the progenitor binary and test the physics of the hydrodynamic pulsation model, a precise measurement of the total flux variation throughout the pulsation cycle is vital. We propose a series of time-resolved HST/STIS ultraviolet observations. These will measure the effective temperature and angular radius with a phase resolution of 0.025 cycles and precision comparable to the velocities provided by recent optical spectroscopy. The shifted and co-added spectrum will explore the surface abundances of iron-group and heavier elements, and hence address questions of origin and evolution. Unleashing the full power of tomography, the dynamical behaviour of the CIV and SiIV absorption lines, formed at optical depths 100 time smaller than the optical helium lines, will be used to explore how pulsations propagate to the outermost layers of the atmosphere and, possibly, into the wind itself. The objective is to obtain time-resolved unltraviolet spectroscopy of a pulsating variable star, with particular emphasis on resolving photospheric structure around minimum radius. The pulsation period is circa 9200 seconds. The fast acceleration passage through minimum radius lasts for less than 900 seconds. The observations will be accomplished in two visits, each of four orbits ... the limit being imposed by the SAA. The gap between visits is not crucial; however, their are constraints on the overall starting orbtit in each block. Repeat observations will be made thoughout each visit with HST/STIS MAMA-FUV G140M + 0.2x0.06. The aim is to observe 95% of all pulsation phases at least three times over, and 100 % at least two times over, which should deliver S/N ~ 20 with a phase resolution of approx 0.05 cycles at good spectral resolution between 1300 and 1600 A. Ideally, we should observe pulsation phases 0.0 - 0.25 four times over. At present, we have selected exposure times of c. 250s, adjusted locally to optimally fill each orbit. Timing Constraint: If the first orbit is chosen poorly, the critical phase through miniumum radius will only be observed twice (rather than three or four times). In practical terms, it is necessary to avoid either block commencing at a time correponding to pulsation phases 0.35 < phi < 0.70. Given a list of orbit start times, we can compute the pulsation phase at the start of each orbit, using the ephemeris given by Jeffery et al. 2015, MNRAS 447, 2836 and the appropriate heliocentric time correction.. There is also a probability that an auto-wavecal will interrupt a sequence during minimum radius. We have to live with this. Stellar Physics 12 false true false false false false AVAILABLE STAR B0-B2 III-I BP PULSATING VARIABLE NO This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 Mean flux between 1300 and 1400 A varies between 3.7E-12 and 5.1E-12 ergs/s/cm^2/A (IUE low resolution data) STIS/FUV-MAMA Spectroscopic No No E140M 1425 /Users/csj/Patt/hst_cycle24/OP-cache/14603_301116-v01.xml Phase windows are not calculated when the gap between schedulable intervals is less than 1 days, assuming no scheduling restrictions for constraint Phase 0.000/0.400. The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. Both visits have a timing requirement -- specifically, to ensure that Rmin is observed twice, the start of the first orbit must not coincide with pulsation phases between 0.30 and 0.90. This has been specified in the Visit Timing Requirement so that T0 correponds to phase -0.30 and the allowed phases are then transposed to lie between 0 and 0.40. (Tic-Visit :proposal-id 14603 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "30-Nov-2016 11:07:11.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 2870928 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14603 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "01" :obset-id "B1" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "01" :obset-id "C1" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14603 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2863 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) true 4 0 During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. /Users/csj/Patt/hst_cycle24/OP-cache/14603_301116-v02.xml Phase windows are not calculated when the gap between schedulable intervals is less than 1 days, assuming no scheduling restrictions for constraint Phase 0.000/0.400. The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. Both visits have a timing requirement -- specifically, to ensure that Rmin is observed twice, the start of the first orbit must not coincide with pulsation phases between 0.30 and 0.90. This has been specified in the Visit Timing Requirement so that T0 correponds to phase -0.30 and the allowed phases are then transposed to lie between 0 and 0.40. (Tic-Visit :proposal-id 14603 :visit-id "02" :proposal-version -1 :trans-version "20160601" :date "30-Nov-2016 11:07:03.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 2870928 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14603 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "02" :obset-id "B2" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 14603 :visit-id "02" :obset-id "C2" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14603 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2863 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "02" :orbit-number 3 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14603 :visit-id "02" :orbit-number 4 :pcs-time 222 :si-vis-utilization 2973 :al-overhead-at-end 81 :internal-dur-at-end 394 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3218 :pcs-gap 0 ) true 4 0 During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation. 1. ETC Run based on an IUE low-resolution spectrum obtained close to UV flux maximum. During occultation.