5871( 7) - 09/13/95 14:42 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5871 Version: 7 Check-in Date: ********** 1.Proposal Title: Rapid UV Variability: The Contribution of Flare Heating in Active Dwarf Atmospheres ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Steven Saar Smithsonian Astrophysical Observatory CoI: Dr. Jay Bookbinder Smithsonian Astrophysical Observatory N ------------------------------------------------------------------------------------ 6. Abstract The question of the contribution of flares and microflares to the non-radiatively heated outer atmospheres of late-type stars has been studied with at best very limited success for over a decade using IUE, a variety of X--ray satellites, and ground-based studies. However, HST presents the possibility for being able to place a firm lower limit on the fraction of the transition region flux that is the direct result of short timescale events. Our analysis of HST data on one M dwarf shows that up to 60 percent attributable to stellar flares and microflares. This leaves little room for the traditional ``quiescent" emission. Such a result, if confirmed for other stars, promises to revitalize the study of these atmospheres, with the recognition that the atmospheres are far more dynamic than static. We are now proposing to observe 3 new targets, including a very youthful solar analog and a fully convective star. ------------------------------------------------------------------------------------ 5871( 7) - 09/13/95 14:42 - [ 2] Observations Description ------------------------ The GHRS G140L grating (LSA), centered at 1523 Angstrom, will be employed to study a series of both chromospheric lines and transition region lines. This setting will allow us to study variability in : chromospheric C I (1561 and 1657 Angstroms), and the Si IV (1400 Angstrom) and C IV (1550 Angstrom) and He II (1640 Angstrom) lines for the transition region. That C IV and Si IV are formed at very similar temperatures, can be used to help confirm our variability analysis. The G140L grating of the GHRS was selected primarily because of its higher sensitivity and lower scattered light below 1500 Angstrom, where most of the lines lie, enabling us to take shorter observations than had we used the FOS. IUE measurement have established fluxes at earth of f_ C IV = 1.9 * 10^-13 ergs cm^-2 s^-1 AA^-1 for HD 129333 (Dorren & Guinan 1994), 3.2 * 10^-13 ergs cm^-2 s^-1 AA^-1 for HD 82558 (Saar, unpublished) and 2.3 * 10^-13 ergs cm^-2 s^-1 AA^-1 for YZ CMi (Linsky et al. 1982). With an efficiency of 67* 10^11 counts s^-1 diode^ -1 per incident erg cm^-2 s^-1 at C IV for the G140L, we should obtain 1.3, 2.1, and 1.9 counts s^-1 at C IV for HD 129333, HD 82558, and YZ CMi, respectively. Since during flares this value can increase by a factor of 10 or more, we should have ample counts to study flares and microflares in these stars. Our request of 4, 6 and 6 orbits, respectively, should yield approximately 4.5, 4 and 4 hours, respectively, of on-target observations. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- We plan an extensive suite of coordinated observations for our targets. Optical spectra of chromospheric diagnostics as well as photometry are planned. We will attempt doppler imaging of HD 129333, and magnetic doppler imaging (e.g., Saar et al. 1992) of HD 82558. Magnetic field measurements of YZ CMi will be carried out from the IRTF with their cryogenic IR echelle. ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5871( 7) - 09/13/95 14:42 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD129333 STAR,G V-IV RA = 14H 39M 0.52S +/- 0.05S, J2000 V = - V = 7.54 +/- 0.10 B-V = 0.61 +/- 0.02 F- DEC = 64D 17' 30.3" +/- 0.3", 31.0 LINE(1550.0) = 1.9 +/- 1.0 E-13 W- PLATE-ID = 00A9 LINE(1550.0) = 1.0 +/- 0.2 Comments: THIS IS A CVZ TARGET. Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1983.291 -0.0236 -0.007 0.032 2 HD82558 STAR,K V-IV RA = 09H 32M 25.86S +/- 0.04S, J2000 V = 14.0 V = 7.79 +/- 0.10 B-V = 0.92 +/- 0.03 F- DEC = -11D 11' 5.7" +/- 0.6", LINE(1550.0) = 3.2 +/- 1.0 E-13 W- PLATE-ID = 0447 LINE(1550.0) = 1.0 +/- 0.2 Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1983.198 -0.0184 0.026 0.080 3 YZ-CMI STAR,M V-IV RA = 07H 44M 40.50S +/- 0.01S, J2000 V = V = 11.2 +/- 0.20 B-V = 1.59 +/- 0.05 F- DEC = 03D 33' 15.3" +/- 0.2", 18.0 LINE(1550.0) = 2.3 +/- 1.0 E-13 W- PLATE-ID = 02V4 LINE(1550.0) = 1.0 +/- 0.2 Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1985.050 -0.0267 -0.455 0.165 5871( 7) - 09/13/95 14:42 - [ 4] Visit: 01 Visit Requirements: CVZ BETWEEN 15-JAN-1996 AND 15-JUL-1996 On Hold Comments: Additional Comments: "BETWEEN" DATES NOT AN ABSOLUTE REQUIREMENT, BUT HIGHLY DESIREABLE FOR COORDINATION WITH GROUND-BASED OBSERVATIONS Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD129333 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN, 1 114.75S ONBOARD ACQ FOR 20-40; SEQ 10-40 NON-INT SEARCH-SIZE=3 Comments: PLEASE NOTIFY P.I. WHEN DATES ARE SCHEDULED OR CHANGED (FOR COORDINATED OBSERVATIONS) IN ACQ EXPECT ABOUT 10 CTS/S, HENCE STEP-TIME 12.75 SEC ------------------------------------------------------------------------------------------------------------------------------------ 20 HD129333 HRS RAPID 2.0 G140L 1523.0 SAMPLE-TIME=1.0 2 4796S Comments: THESE EXPOSURES SHOULD BE SCHEDULED WHEN THE TARGET IS IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 40 HD129333 HRS RAPID 2.0 G140L 1523.0 SAMPLE-TIME=1.0 2 4796S Comments: THESE EXPOSURES SHOULD BE SCHEDULED WHEN THE TARGET IS IN THE CVZ. ------------------------------------------------------------------------------------------------------------------------------------ 5871( 7) - 09/13/95 14:42 - [ 5] Visit: 02 Visit Requirements: BETWEEN 20-OCT-1995 AND 10-NOV-1995 On Hold Comments: Additional Comments: "BETWEEN" DATES NOT AN ABSOLUTE REQUIREMENT, BUT HIGHLY DESIREABLE FOR COORDINATION WITH GROUND-BASED OBSERVATIONS Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD82558 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN, 1 9S ONBOARD ACQ FOR 20 SEARCH-SIZE=3 Comments: PLEASE NOTIFY P.I. WHEN DATES ARE SCHEDULED OR CHANGED (FOR COORDINATED OBSERVATIONS) IN ACQ EXPECT ABOUT 9500 CTS/S, HENCE STEP-TIME 1.0 SEC ------------------------------------------------------------------------------------------------------------------------------------ 20 HD82558 HRS RAPID 2.0 G140L 1523.0 SAMPLE-TIME=1.0 5 2545S ------------------------------------------------------------------------------------------------------------------------------------ 5871( 7) - 09/13/95 14:42 - [ 6] Visit: 03 Visit Requirements: BETWEEN 01-OCT-1995 AND 30-APR-1996 On Hold Comments: Additional Comments: "BETWEEN" DATES NOT AN ABSOLUTE REQUIREMENT, BUT HIGHLY DESIREABLE FOR COORDINATION WITH GROUND-BASED OBSERVATIONS Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 YZ-CMI HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN, 1 90S ONBOARD ACQ FOR 20 SEARCH-SIZE=3 Comments: PLEASE NOTIFY P.I. WHEN DATES ARE SCHEDULED OR CHANGED (FOR COORDINATED OBSERVATIONS) IN ACQ EXPECT ABOUT 350 CTS/S, STEP-TIME = 10.0 SEC ------------------------------------------------------------------------------------------------------------------------------------ 20 YZ-CMI HRS RAPID 2.0 G140L 1523.0 SAMPLE-TIME=1.0 5 2545S ------------------------------------------------------------------------------------------------------------------------------------ 5871( 7) - 09/13/95 14:42 - [ 7] Summary Form for Proposal 5871 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SAMPLE-TIME=1.0 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ BETWEEN 15-JAN-1996 AND 15-JUL-1996 ONBOARD ACQ FOR 20-40; SEQ 10-40 NON-INT BETWEEN 20-OCT-1995 AND 10-NOV-1995 ONBOARD ACQ FOR 20 BETWEEN 01-OCT-1995 AND 30-APR-1996 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140L MIRROR-N2 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD129333 HD82558 YZ-CMI ------------------------------------------------------------------------------------------------------------------------------------