corrected typo in HD number for target 3: now "HD159532" 918957145 ----- Attempting Submission 1 (Thu Sep 08 18:21:02 GMT 2016) ----- ----- Attempting Submission 2 (Sat Jan 14 00:18:04 GMT 2017) ----- Run All Tools was run Cracking the Conundrum of F Supergiant Coronae This is the HST part of a joint Chandra/HST program. BACKGROUND: Mid-F supergiant Alpha Persei, of the eponymous young cluster, is a strong X-ray source, given its minimal FUV emission, with a narrow-line FUV spectrum unlike other yellow supergiants. A slight positional offset in a 1990's ROSAT image suggested that a hyperactive companion might be responsible for the X-ray anomaly. However, a recent Chandra pointing found that the source seen by ROSAT in fact is coincident with Alpha Per. Further, the related supergiant Canopus also exhibits the same X-ray and FUV peculiarities, with a surprising possible connection to Cepheid variables in their FUV low states. THIS PROPOSAL: New X-ray and FUV observations of additional F supergiants could help decide whether the coronal anomalies of Alpha Per and Canopus are due to unseen (unresolved) hyperactive dwarf companions, or instead are a normal attribute of this exotic class, at the extreme edge of convection. This is a key missing piece in the unfolding narrative of hot (1-10 MK) stellar coronae. FUV spectroscopy from HST's ultra-sensitive Cosmic Origins Spectrograph (COS) is a powerful complement to the coronal X-ray imaging by Chandra. The proposed three new F-supergiant targets are comparable in visual brightness to Alpha Persei, which was successfully observed by COS in Cycle 23. COS grating G130M can be used with two CENWAVEs -- 1291 and 1327 -- to help mitigate fixed pattern noise and bridge the detector gaps. The spectral range is 114-147 nm. The two settings allow continuous coverage of the important O I triplet region (130 nm); to hopefully catch the periods of spacecraft night when the oxygen skyglow is significantly diminished so that pristine profiles of the these important stellar chromospheric emissions can be recovered. A single two-orbit visit per target is sufficient, based on anticipated S/N ratios (in the F-star FUV continuum) deduced from COS Spectroscopic ETC runs. In each visit, the initial acquisition is done via a 9-step spiral search, followed by a PEAKXD, and then by a PEAKD, all in dispersed light with G130M-1327, to accurately center these FUV-bright targets. CENWAVE 1327 is the reddest setting of G130M, so captures the highest intensity part of the F star photospheric continuum, which rises steeply toward longer wavelengths through the FUV region. Acquisition exposure times (to achieve S/N~40) were derived from the COS ETC using a Castelli-Kurucz F0I model, normalized to the individual visual magnitudes, as verified against IUE spectra (which tend to have best exposures for these stars in the 150-170 nm interval). The inferred ACQ exposure times then were boosted by factors of 7--10, to be on the safe side (since IUE FUV spectra of F-stars are contaminated to an unknown degree by scattered light). The chosen exposure times, 4.0-5.2 s, are similar to the 5 s that was used for cooler (F5I) Alpha Persei, and which produced a successful acquisition for that target. Following the centering process, a G130M-1327 spectrum is taken, with equal exposures at each of the four standard FP-POS steps, to fill out the first orbital visibility period. The second orbit is occupied by a G130M-1291 exposure, also split into standard FP-POS sub-exposures. Based on IUE and FUSE spectra, the three targets are similar in activity level to Alpha Per, so there is no issue with COS bright limits at Lyman Alpha (interstellar absorption also likely will strongly attenuate any intrinsic hydrogen emission from these stars). COOL STARS 12 false false false false false 0.0 0.0 false SUPPORTED STAR F0-F2 NO ALP-LEP J2000 J2000 STAR F0-F2 NO IOT-CAR J2000 J2000 STAR F0-F2 NO THETA-SCO J2000 J2000 STIS/FUV-MAMA Spectroscopic No No E140M 1425 STIS/FUV-MAMA Spectroscopic No No E140M 1425 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14848 :visit-id "A0" :proposal-version -1 :trans-version "20160601" :date "08-Sep-2016 12:12:24.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 835216 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14848 :visit-id "A0" :obset-id "A0" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14848 :visit-id "A0" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2888 :al-overhead-at-end 0 :internal-dur-at-end 67 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3221 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14848 :visit-id "A0" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2997 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3221 :pcs-gap 0 ) false 2 0 ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14848 :visit-id "B0" :proposal-version -1 :trans-version "20160601" :date "08-Sep-2016 12:13:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 800400 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14848 :visit-id "B0" :obset-id "B0" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14848 :visit-id "B0" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3123 :al-overhead-at-end 0 :internal-dur-at-end 57 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3456 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14848 :visit-id "B0" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3233 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3456 :pcs-gap 0 ) false 2 0 ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /private/var/folders/wk/kryl66hd5l148rf9p2bj1m2c0000gn/T/OPVisit1891901977717596831.xml (Tic-Visit :proposal-id 14848 :visit-id "C0" :proposal-version -1 :trans-version "20160601" :date "13-Jan-2017 17:14:58.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 800400 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14848 :visit-id "C0" :obset-id "C0" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14848 :visit-id "C0" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2974 :al-overhead-at-end 0 :internal-dur-at-end 57 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14848 :visit-id "C0" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3085 :al-overhead-at-end 0 :internal-dur-at-end 341 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3307 :pcs-gap 0 ) true 2 0 ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin. ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin. ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin.