14848( 3) - 17-Jan-2017 15:09:23 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14848 Version: 3 Check-in Time: 17-Jan-2017 15:09:23 STScI Edit Number: 1 Title Cracking the Conundrum of F Supergiant Coronae ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Thomas R. Ayres University of Colorado at Boulder Y ------------------------------------------------------------------------------------ Abstract 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. ------------------------------------------------------------------------------------ Observations Description ------------------------ 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 14848( 3) - 17-Jan-2017 15:09:23 - [ 2] 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). ------------------------------------------------------------------------------------ 14848( 3) - 17-Jan-2017 15:09:23 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD36673 STAR, F0-F2 RA=05H32M43.8160S +/- 1.0", J2000 V = 0.0 V = +2.57 +/- 0.1 DEC=-17D49'20.24" +/- 1.0" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 2.520980861127293E-4 0.0012 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD80404 STAR, F0-F2 RA=09H17M5.4070S +/- 1.0", J2000 V = 0.0 V = +2.26 +/- 0.1 DEC=-59D16'30.84" +/- 1.0" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.0024661658204725564 0.012 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 3 HD159532 STAR, F0-F2 RA=17H37M19.1300S +/- 1.0", J2000 V = 0.0 V = +1.86 +/- 0.1 DEC=-42D59'52.18" +/- 1.0" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 5.013356785852567E-4 -0.0031 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 14848( 3) - 17-Jan-2017 15:09:23 - [ 4] Visit: A0 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD36673 COS/FUV ACQ/SEA PSA G130M 1327 SCAN-SIZE=3, STEP-SIZE=1.767, 1 5.2 S (5.2 RCH CENTER=FLUX-WT-FLR S) Comments: ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 2 HD36673 COS/FUV ACQ/PEA PSA G130M 1327 1 5.2 S (5.2 KXD S) Comments: ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 3 HD36673 COS/FUV ACQ/PEA PSA G130M 1327 NUM-POS=5, STEP-SIZE=0.9, 1 5 S (5 S) KD CENTER=FLUX-WT-FLR Comments: ETC predicts S/N~40 in 0.7 s. texp increased x7 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 4 HD36673 COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=308, FP-POS=ALL 1 418 S G (1672 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD36673 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=537, FP-POS=ALL 1 647 S G (2588 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD36673 1 COS/FUV ACQ/SEA PSA G130M 1327 none none none none 1 N/A RCH HD36673 2 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KXD HD36673 3 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KD HD36673 4 COS/FUV TIME-TA PSA G130M 1327 none none none 1 1 N/A G HD36673 4 COS/FUV TIME-TA PSA G130M 1327 none none none 2 1 N/A G HD36673 4 COS/FUV TIME-TA PSA G130M 1327 none none none 3 1 N/A G HD36673 4 COS/FUV TIME-TA PSA G130M 1327 none none none 4 1 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 5] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD36673 5 COS/FUV TIME-TA PSA G130M 1291 none none none 1 2 N/A G HD36673 5 COS/FUV TIME-TA PSA G130M 1291 none none none 2 2 N/A G HD36673 5 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 N/A G HD36673 5 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 6] Visit: B0 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD80404 COS/FUV ACQ/SEA PSA G130M 1327 SCAN-SIZE=3, STEP-SIZE=1.767, 1 5.2 S (5.2 RCH CENTER=FLUX-WT-FLR S) Comments: ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 2 HD80404 COS/FUV ACQ/PEA PSA G130M 1327 1 5.2 S (5.2 KXD S) Comments: ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 3 HD80404 COS/FUV ACQ/PEA PSA G130M 1327 NUM-POS=5, STEP-SIZE=0.9, 1 5.2 S (5.2 KD CENTER=FLUX-WT-FLR S) Comments: ETC predicts S/N~40 in 0.6 s. texp increased x8 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 4 HD80404 COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=374, FP-POS=ALL 1 484 S G (1936 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD80404 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=596, FP-POS=ALL 1 706 S G (2824 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD80404 1 COS/FUV ACQ/SEA PSA G130M 1327 none none none none 1 N/A RCH HD80404 2 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KXD HD80404 3 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KD HD80404 4 COS/FUV TIME-TA PSA G130M 1327 none none none 1 1 N/A G HD80404 4 COS/FUV TIME-TA PSA G130M 1327 none none none 2 1 N/A G HD80404 4 COS/FUV TIME-TA PSA G130M 1327 none none none 3 1 N/A G HD80404 4 COS/FUV TIME-TA PSA G130M 1327 none none none 4 1 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 7] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD80404 5 COS/FUV TIME-TA PSA G130M 1291 none none none 1 2 N/A G HD80404 5 COS/FUV TIME-TA PSA G130M 1291 none none none 2 2 N/A G HD80404 5 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 N/A G HD80404 5 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 8] Visit: C0 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD159532 COS/FUV ACQ/SEA PSA G130M 1327 SCAN-SIZE=3, STEP-SIZE=1.767, 1 4.2 S (4.2 RCH CENTER=FLUX-WT-FLR S) Comments: ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 2 HD159532 COS/FUV ACQ/PEA PSA G130M 1327 1 4.0 S (4 KXD S) Comments: ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 3 HD159532 COS/FUV ACQ/PEA PSA G130M 1327 NUM-POS=5, STEP-SIZE=0.9, 1 4.0 S (4 KD CENTER=FLUX-WT-FLR S) Comments: ETC predicts S/N~40 in 0.4 s. texp increased x10 for extra margin. ------------------------------------------------------------------------------------------------------------------------------------ 4 HD159532 COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=341, FP-POS=ALL 1 451 S G (1804 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD159532 COS/FUV TIME-TA PSA G130M 1291 BUFFER-TIME=559, FP-POS=ALL 1 669 S G (2676 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD159532 1 COS/FUV ACQ/SEA PSA G130M 1327 none none none none 1 N/A RCH HD159532 2 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KXD HD159532 3 COS/FUV ACQ/PEA PSA G130M 1327 none none none none 1 N/A KD HD159532 4 COS/FUV TIME-TA PSA G130M 1327 none none none 1 1 N/A G HD159532 4 COS/FUV TIME-TA PSA G130M 1327 none none none 2 1 N/A G HD159532 4 COS/FUV TIME-TA PSA G130M 1327 none none none 3 1 N/A G HD159532 4 COS/FUV TIME-TA PSA G130M 1327 none none none 4 1 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 9] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD159532 5 COS/FUV TIME-TA PSA G130M 1291 none none none 1 2 N/A G HD159532 5 COS/FUV TIME-TA PSA G130M 1291 none none none 2 2 N/A G HD159532 5 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 N/A G HD159532 5 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 N/A G 14848( 3) - 17-Jan-2017 15:09:23 - [ 10] Summary Form for Proposal 14848 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=308, BUFFER-TIME=341, BUFFER-TIME=374, BUFFER-TIME=537, BUFFER-TIME=559, BUFFER-TIME=596, CENTER=FLUX-WT-FLR, FP-POS=ALL, NUM-POS=5, SCAN-SIZE=3, STEP-SIZE=0.9, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD159532, HD36673, HD80404 ------------------------------------------------------------------------------------------------------------------------------------