7733( 4) - 07/24/98 10:46 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7733 Version: 4 Check-in Date: 24-Jul-1998 10:45:00 1.Proposal Title: Distant Futures of Solar Activity ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/CAR 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Thomas Ayres University of Colorado CASA CoI: Kenneth Carpenter NASA/Goddard Space Flight Center N CoI: Richard Robinson Computer Sciences Corp. N CoI: Alex Brown University of Colorado CASA N CoI: Graham Harper University of Colorado CASA N CoI: Philip Bennett University of Colorado CASA N CoI: Jeffrey Linsky University of Colorado JILA N CoI: Dainis Dravins Lund Observatory N CoI: Philip Judge High Altitude Observatory N ------------------------------------------------------------------------------------ 5. Abstract We will explore possible future fates of solar magnetic activity through high-S/N ultraviolet spectra of the ancient Sun analog, Arcturus (K2 III). The fundamental mechanisms that drive the hot (T>10^6 K) coronae of cool stars remain elusive. Solving the mystery is a central theme of the ``solar-stellar connection;'' whose importance extends beyond astronomy to areas ranging from basic plasma physics to solar-terrestrial relations. A significant property of the activity is that it subsides with age: G dwarfs in young clusters are intense coronal sources, whereas old low mass K giants are so feable in soft X-rays that most are below current detection limits. For that reason, historical studies of activity have been biased towards the younger stars. Now HST/STIS easily can record faint coronal proxies (like Si IV and C IV) in nearby cool subgiants and giants, thereby mitigating the de facto age discrimination. In the solar neighborhood the brightest single star of advanced age (9--11 Gyr) is Alpha Bootis (K2 III). Previous studies have placed the archetype red giant firmly in the ``coronal graveyard.'' Our project focuses on understanding the ``basal'' chromosphere; molecular cooling catastrophes and the structure of the passive ``COmosphere;'' the dynamics and energy balance of the residual subcoronal gas; and mass loss mechanisms. (This program is a carryover from a failed Cycle 5 GHRS observation.) ------------------------------------------------------------------------------------ 7733( 4) - 07/24/98 10:46 - [ 2] Observations Description ------------------------ The objective of the original GHRS Cycle 5 proposal was to obtain medium- resolution and echelle spectra of selected FUV and MUV intervals containing key diagnostic emission lines. GHRS observations were attempted late in Cycle 5, but mostly failed owing to repeated loss-of-locks on the guide stars which prevented a critical peak-up into the small science aperture. In the carryover STIS program, the specification of the observing sequence is greatly simplified because the primary settings of the FUV and MUV medium-res echelles (E140M and E230M, respectively) together cover most of the desired spectral range. The important interval extending from the Fe II resonance lines (2600 A) to Mg II h and k (2800 A) can be observed with one setting of the high-res echelle (E230H). The predicted peak count rate at the top of the k line is 18 cps/pixel in the MUV-MAMA (as reported by the STIS exposure time simulator). The global count rate (from the average continuum level of ~1E-11 ergs/cm^2/s/A) is an order of magnitude below the global bright limit. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7733( 4) - 07/24/98 10:46 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD124897 STAR, K III-I, Corona, RA=14H 15M 39.68S +/- 0.05S, 2000 V = -5 V = -0.05+/-0.1 Wind DEC=19D 10' 56.7" +/- 1" B-V = +1.23+/-0.1 F-CONT(2800)=15+/-5e-12 F-CONT(2600)=5+/-2e-12 F(2796)=400+/-40e-12 TYPE=K2III Comments: Positions & Proper Motions from Hipparcos Catalogue; MUV fluxes from high-res IUE spectra Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.0772 -1.998 0.090 7733( 4) - 07/24/98 10:46 - [ 4] Visit: 01 Visit Priority: 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 HD124897 STIS/C ACQ F25ND5 MIRROR 1 0.1 S ONBOARD ACQ FOR 2 GS ACQ CD SCENARIO SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 2 HD124897 STIS/C ACQ/PEA 0.1X0.2 G430M 3936 1 0.1 S ONBOARD ACQ FOR 3 CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 HD124897 STIS/N ACCUM 0.1X0.2 E230H 2713 BINAXIS1=NO,BINAXIS2=NO 1 1225 S UV-MAM A Comments: ONBOARD ACQ FOR 4 ------------------------------------------------------------------------------------------------------------------------------------ 4 HD124897 STIS/C ACQ/PEA 0.2X0.0 G430M 3936 1 0.1 S ONBOARD ACQ FOR 5-6 CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 5 HD124897 STIS/N ACCUM 0.2X0.0 E230M 2124 BINAXIS1=NO,BINAXIS2=NO 1 2450 S UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 6 HD124897 STIS/F ACCUM 0.2X0.0 E140M 1425 BINAXIS1=NO,BINAXIS2=NO 2 2450 S UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 7733( 4) - 07/24/98 10:46 - [ 5] Summary Form for Proposal 7733 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND5 0.1X0.2 0.2X0.06 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BINAXIS1=NO BINAXIS2=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 GS ACQ SCENARIO SINGLE ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 5-6 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430M E230H E230M E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD124897 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 3936 2713 2124 1425 ------------------------------------------------------------------------------------------------------------------------------------