6067( 0) - 07/18/95 19:46 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6067 Version: ********** Check-in Date: ********** 1.Proposal Title: Hot Times in the Hertzsprung Gap ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Thomas Ayres University of Colorado CASA ------------------------------------------------------------------------------------ 6. Abstract I propose to explore the early evolution of magnetic activity in F-G0 giants crossing the Hertzsprung gap. The giant branch evolution of 2-4 solar mass stars provides a vital test of our understanding of magnetic Dynamo action, coronal heating, and winds. The ``X-ray deficiency'' of the F-G0 giants represents a clear distinction compared to cooler Main Sequence stars. Possibly connected with the deficiency is the newly recognized warm wind of the G0 secondary of Capella, as well as indications for a previously unrecognized ``broad component'' in its high excitation emissions like C IV 1548. The mass loss rate of the Capella wind is low, but could be quite important in braking the fast stellar rotation. The broad components might be associated with the wind, but more likely are due to highly dynamic phenomena in the subcoronal atmosphere; perhaps the stellar equivalent of solar ``transition zone explosive events.'' These new aspects of stellar activity warrant detailed consideration. My strategy is to use the HST/GHRS to record key FUV emissions -- spanning the broad temperature range 10,000 K - 200,000 K -- with high S/N in archetype Hertzsprung gap stars. The objective is to measure line widths, profile asymmetries, circumstellar absorptions, systematic Doppler shifts, and density sensitive line ratios. Such diagnostics will be used to constrain existing physical models, and develop new ones. The HST spectra will strongly complement ongoing ROSAT & EUVE work. ------------------------------------------------------------------------------------ 6067( 0) - 07/18/95 19:46 - [ 2] Observations Description ------------------------ In the table, below, I summarize the changes to the original Phase I proposed observation plan which I have made based on new information -- as well as experience with a current Cyc-4 program (completed this past fall) -- not available to me when I designed the original program. Target 1: Beta Cas (2 orbits in CVZ) ==================================================================== Original Phase I New Phase II -------------------------- --- ------------------------- A0: G160M/LSA/1222 43.5M -[ 10: G140M/ssa/1216 23.6M [ 11: G140M/LSA/1230 39.9M A1: G160M/LSA/1400 49.0M 20: G140M/LSA/1402 49.9M A2: G160M/LSA/1550 21.8M 30: G140M/LSA/1553 25.5M -------------------------- --------------------- ------- Notes: The major deviation from the original program is the use of GHRS Side 1 instead of Side 2. The target is too bright to acquire with N2, but not with N1. The use of the attenuated A2 mirror was judged to impose an unacceptable overhead in the face of the small amount of time (2 orbits) available for the target. The target is relatively bright and the Side 1 medium -resolution G140M grating provides higher resolving power than G160M with minimal loss of sensitivity. This is particularly important in the H I Ly- alpha region where the measurement of the interstellar D I absorption not only is significant in itself, but its known radial velocity in that line of sight also provides an empirical way to check the centering of the target in the ssa (where a few tenths of a diode offset from the center could impose a systematic wavelength scale shift of 5 km/s or more, above and beyond the other -- more managable -- errors like thermal, GIMP, & grating rotation). In addition, SPYBALs will be used in place of explicit WAVEcals, because experience with a Cyc-4 program (three targets observed) shows that the former are sufficiently accurate. --------------------------------------------------------------------- - Target 2: Psi3 Psc (4 orbits [w/ occultations]) ==================================================================== Original Phase I New Phase II -------------------------- --- ------------------------- 10: ECH-B/ssa/2799 12.7M A0: G160M/LSA/1222 49.0M -[ 20: G160M/ssa/1222 14.5M [ 21: G160M/LSA/1222 40.8M A1: G160M/LSA/1400 54.0M 30: G160M/LSA/1402 50.8M A2: G160M/LSA/1550 21.8M 40: G160M/LSA/1553 19.0M -------------------------- ----------------- ----------- Notes: The major deviation from the original program is the addition of a short exposure of the Mg II 2800 A doublet with ECH-B. In the original proposal, I suggested that little additional could be learned from the Mg II features -- beyond what would be seen in H I Ly-alpha -- particularly because the cores would be washed out by the fast rotation of the star. In the interim, however, two new developments have significantly increased the value of the high-resolution Mg II spectra. First, Cyc-4 observations of Mg II in 31 Comae -- a Hertzsprung-gap star very similar to Psi3 Psc -- show that the Mg II cores are very asymmetric, a fact that cannot be deduced from the lower resolution IUE echelle spectra because of the contamination by the ISM absorptions (which are blurred at the 10,000 resolving power of IUE, but are fully resolved at R=85,000 of ECH-B). The Mg II asymmetry appears to be repeated in other strong lines like Ly-alpha and Si III 1206, but on a constant wavelength scale rather than a constant velocity scale (the latter being expected for a normal dynamical explanation of the core asymmetry). The puzzle of the asymmetric chromospheric emissions possibly has a great deal to do with the ``X-ray deficiency'' of the Hertzsprung-gap giants, which is one of the central themes of the proposed Cyc-5 investigation. The second development concerning Mg II is the use of the ISM absorptions not only to probe the physical conditions of the interstellar gas along that sightline, but also as an empirical test of the centering of the target in the ssa. In practice, the ECH-B observation provides an accurate measurement of the ISM velocity, because even a few tenths of a diode de-centering of the target would impose at most a 1 km/s shift of the velocity scale (because the diodes are ``small'' in wavelength units in the echelle mode). One then can measure the apparent displacement of the ISM H I absorption (or D I feature if visible) in the G160M/ssa spectrum (where the diodes are ``big'' in wavelength units): the velocity difference between the ECH-B and G160M observations is a measure of the spatial offset of the target in the ssa along the dispersion direction. That offset (converted to units of diodes) then can be applied to other wavelength settings of G160M (or other gratings). The availability of the in situ calibration of the target de-centering is well worth the small time and overhead of the additional exposure. Note, also, that the original G160M/LSA observation of Ly-alpha (and Si III 1206 + N V 1238) has been split into a short ssa integration and a deeper LSA exposure. The purpose of the former is to record the ISM absorption core of the H I emission feature free of geocoronal contamination. Again, experience with a Cyc-4 program (three targets) has demonstrated the importance of the spit-exposure strategy. ------- --------------------------------------------------------------- Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6067( 0) - 07/18/95 19:46 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6067( 0) - 07/18/95 19:46 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD432 STAR, Corona, Wind RA=00H 09M 10.70S +/- 0.05S, 2000 V = +11 V= +2.27 +/- 0.1 DEC=+59D 08' 59.2" +/- 1" B-V= +0.34 +/- 0.1 TYPE= F2III Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0679 -0.177 0.072 2 HD6903 STAR, G III-I, Corona, RA=01H 09M 49.18S +/- 0.05S, 2000 V = +11 V= +5.55 +/- 0.1 Wind DEC=+19D 39' 30.0" +/- 1" B-V= +0.69 +/- 0.1 TYPE= G0III Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.0004 0.013 0.000 6067( 0) - 07/18/95 19:46 - [ 5] Visit: 01 Visit Requirements: CVZ On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD432 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 9S ONBOARD ACQ FOR 2 SEARCH-SIZE=3 Comments: STEP-TIME = 1 SEC (approx. 3000 cnts in STEP- TIME) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD432 HRS ACQ/PEA 0.25 MIRROR-N1 SEARCH-SIZE=5 1 38.75S ONBOARD ACQ FOR 10-30 KUP Comments: STEP-TIME = 1.55 SEC ------------------------------------------------------------------------------------------------------------------------------------ 10 HD432 HRS ACCUM 0.25 G140M 1216.5 COMB=FOUR, STEP 1 1414.4S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=STD Comments: Expect S/N>60 @ Ly-alp thus FP-SPLIT it ------------------------------------------------------------------------------------------------------------------------------------ 11 HD432 HRS ACCUM 2.0 G140M 1230.5 COMB=FOUR, STEP 4 598.4S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: D1 less affected by GIMP; S/N=30 @ N V: no FP -SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 20 HD432 HRS ACCUM 2.0 G140M 1402 COMB=FOUR, STEP 5 598.4S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=50 @ Si IV: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 30 HD432 HRS ACCUM 2.0 G140M 1553 COMB=FOUR, STEP 3 489.6S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=30 @ C IV: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 6067( 0) - 07/18/95 19:46 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD6903 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN, 1 1.8S ONBOARD ACQ FOR 2 SEARCH-SIZE=3 Comments: STEP-TIME = 0.2 SEC (approx. 54,000 cnts in STEP-TIME) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD6903 HRS ACQ/PEA 0.25 MIRROR-N2 SEARCH-SIZE=5 1 5S ONBOARD ACQ FOR 10-40 KUP Comments: STEP-TIME = 0.2 SEC ------------------------------------------------------------------------------------------------------------------------------------ 10 HD6903 HRS ACCUM 0.25 ECH-B20 2799 COMB=FOUR, STEP 2 380.8S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: D2 more affected by GIMP; S/N=50 @ Mg II k: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 20 HD6903 HRS ACCUM 0.25 G160M 1222.5 COMB=FOUR, STEP 2 435.2S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=25 @ Ly-alp: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 21 HD6903 HRS ACCUM 2.0 G160M 1222.5 COMB=FOUR, STEP 6 408S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=50 @ Ly-alp; =7 @ N V: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 30 HD6903 HRS ACCUM 2.0 G160M 1402 COMB=FOUR, STEP 7 435.2S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=18 @ Si IV: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 40 HD6903 HRS ACCUM 2.0 G160M 1553 COMB=FOUR, STEP 3 380.8S -PATT=DEF, DOPPLER=DEF, FP -SPLIT=NO Comments: S/N=15 @ C IV: no FP-SPLIT ------------------------------------------------------------------------------------------------------------------------------------ 6067( 0) - 07/18/95 19:46 - [ 7] Summary Form for Proposal 6067 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SEARCH-SIZE=5 FP-SPLIT=STD FP-SPLIT=NO DOPPLER=DEF STEP-PATT=DEF COMB=FOUR ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 10-30 ONBOARD ACQ FOR 10-40 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140M MIRROR-N2 ECH-B20 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD432 HD6903 ------------------------------------------------------------------------------------------------------------------------------------