9271( 3) - 04/03/02 06:40 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9271 Version: 3 Check-in Date: 03-Apr-2002 06:39:28 1.Proposal Title: Coronal Dynamics and the Complete Flare Energy Budget for the M Dwarf AD Leo ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Alexander Brown University of Colorado at Boulder CoI: Rachel A. Osten CASA N CoI: Dr. Thomas Ayres CASA N CoI: Dr. Graham Harper CASA N CoI: Joanna M. Brown Swarthmore College N ------------------------------------------------------------------------------------ 5. Abstract We will carry out six orbits (two visits of 4 and 2 orbits duartaion) of STIS E140M TIME-TAG mode spectroscopy of the active red dwarf star AD Leo, coordinated wth Chandra-HETGS (50 ksec) observations, to accurately measure for the first time the complete energy budget of stellar coronal flares. FUV observations of the Fe XXI 1354 A coronal forbidden lines are needed from STIS to determine the dynamical energy losses of the flares. Chandra HETGS spectra will be used to measure the temporal changes in the coronal emission measure, temperature, density, and elemental abundances. AD Leo is one of the brightest dMe stars in the ultraviolet and X-ray regions and flaring rate data suggests that we should see about 10 moderate (factor of a few) and one large (factor of 10-20 enhancement) flares in a 30 hour observation. Ground-based optical and radio monitoring will also be attempted. ------------------------------------------------------------------------------------ 9271( 3) - 04/03/02 06:40 - [ 2] Observations Description ------------------------ The basic STIS FUV observations are straightforward; however, scheduling of these simultaneous observations with Chandra will require careful planning. The target will be acquired with the CCD using the F25ND3 filter (V=9.4), and then a PEAK-UP will be performed using a very narrow ND-filtered aperture. The E140M/FUV-MAMA observations are carried out with the 0.2X0.2 "photometric" aperture in TIME-TAG mode. Based on simulations with the STIS exposure time calculator, we estimate a typical global count rate (during quiescence) of 75 cps, completely dominated by the 1215 A hydrogen Lyman alpha feature (peak count rate ~ 0.1 cps/px). During a flare, the H I flux might triple, but the count rate at the line peak would still be less than 1 cps/px, and the global rate would be only about 200 cps. The C IV doublet might brighten substantially more than Lyman alpha, but even a 10X flux increase would still yield a peak count rate of less than 1 cps/px, and only a minimal increase in the global count rate. Given these estimates, the appropriate BUFFER-TIME would be 10, 000 S, well in excess of the maximum exposure time of 2880 S, so we set BUFFER-TIME to half the exposure time in each orbit. The 6 allocated HST orbits have been divided into one 4 orbit visit and one 2 orbit visit to maximize simultaneity with the Chandra observation. The scheduling restrictions for coordinated observations with Chandra are significant; the currently scheduled window is the week of 2002 May 27 - June 2. The HST visits should be scheduled on consecutive days. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- It is essential to have the STIS observations scheduled as much as possible to occur during the long Chandra exposure, which will last for most of a day. ------------------------------------------------------------------------------------ 9271( 3) - 04/03/02 06:40 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 BD+20D2465 STAR, M V-IV, CORONA RA=10H 19M 36.915S +/- 0.3", J2000 V = V = +9.43+/-0.1 DEC=+19D 52' 12.4" +/- 0.3", +10.8 B-V = +1.54+/-0.1 PLATE-ID=026A TYPE=M3.5V F-CONT(1600)=3+/-2e-15 F-LINE(1215)=10+/-1e-13 W-LINE(1215)=2.7+/-0.4 F-LINE(1548)=6+/-1e-13 W-LINE(1548)=0.25 Coordinate Source: GUIDE_STAR_CATALOG Comments: Proper Motions from Hipparcos Input Catalogue; Identical coordinates used successfully in program 8613. FUV fluxes from IUE spectra; FWHMs from GHRS spectra of target and STIS spectra of similar objects (AU Mic); the fluxes are ergs/cm^2/s/A at the line peak. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.96 -0.0355 -0.046 0.213 9271( 3) - 04/03/02 06:40 - [ 4] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 27-MAY-2002 AND 03-JUN-2002; SEQ 01, 02 WITHIN 24 H On Hold Comments: Additional Comments: Scheduling window choosen to allow simultaneous STIS and Chandra observations. Essential to schedule observation within the ~1 day duration of the Chandra X-ray Observatory pointing on the same target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 11 BD+20D2465 STIS/C ACQ F25ND3 MIRROR 1 1 S CD Comments: S/N=97, 6000 e- BRIGHTEST PIXEL ------------------------------------------------------------------------------------------------------------------------------------ 12 BD+20D2465 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 1 S CD K 5ND Comments: S/N=113, 8000 e- BRIGHTEST PIXEL ------------------------------------------------------------------------------------------------------------------------------------ 13 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=875. 1 1750 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 14 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=1440. 1 2880 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 15 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=1440. 1 2880 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 16 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=1440. 1 2880 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9271( 3) - 04/03/02 06:40 - [ 5] Visit: 02 Visit Priority: Visit Requirements: BETWEEN 27-MAY-2002 AND 03-JUN-2002; SEQ 01, 02 WITHIN 24 H On Hold Comments: Additional Comments: Scheduling window choosen to allow simultaneous STIS and Chandra observations. Essential to schedule observation within the ~1 day duration of the Chandra X-ray Observatory pointing on the same target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 21 BD+20D2465 STIS/C ACQ F25ND3 MIRROR 1 1 S CD Comments: S/N=97, 6000 e- BRIGHTEST PIXEL ------------------------------------------------------------------------------------------------------------------------------------ 22 BD+20D2465 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 1 S CD K 5ND Comments: S/N=113, 8000 e- BRIGHTEST PIXEL ------------------------------------------------------------------------------------------------------------------------------------ 23 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=875. 1 1750 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 24 BD+20D2465 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=1440. 1 2880 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9271( 3) - 04/03/02 06:40 - [ 6] Summary Form for Proposal 9271 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 0.2X0.05ND 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=875. BUFFER-TIME=1440. ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 27-MAY-2002 AND 03-JUN-2002; SEQ 01, 02 WITHIN 24 H ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names BD+20D2465 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1425 ------------------------------------------------------------------------------------------------------------------------------------