9464( 2) - 02/15/02 16:12 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9464 Version: 2 Check-in Date: 15-Feb-2002 16:06:14 1.Proposal Title: Exploring the Role of Acoustic Heating in Cool Dwarfs and Subgiants ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Steven Saar Smithsonian Institution Astrophysical Observatory CoI: Dr. Philip Judge High Altitude Observatory, National Center N for Atmospheric Research CoI: Dr. Mats Carlsson Institute of Theoretical Astrophysics, N Oslo Univ. CoI: Dr. Manfred Cuntz University of Texas, Arlington N ------------------------------------------------------------------------------------ 5. Abstract Recent observations cast doubt on the importance of acoustic waves for chromospheric heating in stars. These include low upper limits to their contribution to upper layers of the solar chromosphere, and evidence for significant magnetic heating contribution even in ``basal" activity stars. These findings contradict the widely accepted picture that acoustic heating accounts for a significant fraction, the ``basal component'', of chromospheric heating in inactive stars. To help resolve this issue, we propose to observe two very inactive stars with significantly different properties to search for specific signatures of upward propagating acoustic waves: blue-shifts and enhanced blue wings in chromospheric lines. Solar data show that the degree of blue-shift can be used to estimate the acoustic contribution to chromospheric heating. We will compare the data to HST spectra of similar stars, and solar spectra from the SUMER instrument on SOHO. Lack of a significant acoustic signature in our targets would indicate that magnetic heating generated by a local (turbulent, non-cycling) dynamo is responsible for the basal component of chromospheric heating in inactive stars. Our targets may be in a phase analogous to the solar Maunder minimum, and the HST spectra might serve as a proxy for the solar spectrum in this state. The spectra will also be used for emission measure analysis differentially between the Sun and solar-like stars. ------------------------------------------------------------------------------------ 9464( 2) - 02/15/02 16:12 - [ 2] Observations Description ------------------------ Since our targets are bright, we use the narrowband O III filter to acquire, where 0.1 s yields S/N = 155 (1.5e4 electrons in brightest pixel) for HD142373, and S/N = 257 (4e4 electrons in brightest pixel) for HD23249. To obtain the most accurate wavelengths, we peakup in a smaller slit (0.3x0.5ND) than the science slit (0.2x0.2) and be sure to get autowavecals for every orbit. A 0.1s peakup yields S/N = 91 (0.53e4 electrons peak) for HD142373, and S/N = 151 (1.4e4 electrons peak) for HD23249. The resulting spectra should show e.g., S/N = 25 per resolution element in the Si IV line (1393 A). Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9464( 2) - 02/15/02 16:12 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD23249 STAR, K V-IV RA=3H 43M 14.96S +/- 0.0S, DEC=- J2000 V=-6 V = 3.52+/-0.01 9D 45' 54.7" +/- 0.0" B-V = 0.92+/-0.01 F(1334)=2.1+/-0.2e-14 TYPE=K1IV Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B1991.25 -0.0062 0.7422 0.11058 2 HD142373 STAR, F3-F9 RA=15H 52M 40.19S +/- 0.0S, J2000 V=-56 V = 4.59+/-0.00 DEC=+42D 27' 00.0" +/- 0.0" B-V = 0.56+/-0.01 F(1334)=0.7+/-0.1e-14 TYPE=F8V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B1991.25 0.03966 0.6295 0.06308 9464( 2) - 02/15/02 16:12 - [ 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 HD23249 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 0.1 S CD III ------------------------------------------------------------------------------------------------------------------------------------ 2 HD23249 STIS/C ACQ/PEA 0.3X0.0 MIRROR 1 0.1 S CD K 5ND ------------------------------------------------------------------------------------------------------------------------------------ 3 HD23249 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1862 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 HD23249 STIS/F ACCUM 0.2X0.2 E140M 1425 3 2897 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9464( 2) - 02/15/02 16:12 - [ 5] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 5 HD142373 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 0.1 S CD III ------------------------------------------------------------------------------------------------------------------------------------ 6 HD142373 STIS/C ACQ/PEA 0.3X0.0 MIRROR 1 0.1 S CD K 5ND ------------------------------------------------------------------------------------------------------------------------------------ 7 HD142373 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1988 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8 HD142373 STIS/F ACCUM 0.2X0.2 E140M 1425 3 3022 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9464( 2) - 02/15/02 16:12 - [ 6] Visit: 03 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 ------------------------------------------------------------------------------------------------------------------------------------ 9 HD142373 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 0.1 S CD III ------------------------------------------------------------------------------------------------------------------------------------ 10 HD142373 STIS/C ACQ/PEA 0.3X0.0 MIRROR 1 0.1 S CD K 5ND ------------------------------------------------------------------------------------------------------------------------------------ 11 HD142373 STIS/F ACCUM 0.2X0.2 E140M 1425 1 1988 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 12 HD142373 STIS/F ACCUM 0.2X0.2 E140M 1425 3 3022 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9464( 2) - 02/15/02 16:12 - [ 7] Summary Form for Proposal 9464 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50OIII 0.3X0.05ND 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD23249 HD142373 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 ------------------------------------------------------------------------------------------------------------------------------------