6551( 5) - 06/03/96 13:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6551 Version: 5 Check-in Date: 03-Jun-1996 13:43:40 1.Proposal Title: Fishing in the Coronal Graveyard ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COOL STARS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Thomas Ayres University of Colorado CASA CoI: Alex Brown University of Colorado CASA N CoI: Graham Harper University of Colorado CASA N ------------------------------------------------------------------------------------ 6. Abstract We propose a far-UV spectroscopic survey of K2-K4 giants. Hot coronae (T> 10^6 K) are rare or absent in single giant stars to the right of a boundary in the H-R diagram near K0 (``Linsky-Haisch dividing line''). The early-K giants are such slow rotators that the absence of Dynamo-generated magnetic activity is natural. Nevertheless, Gamma Draconis (K5 III) unexpectedly was detected in the coronal proxy C IV by HST/GHRS, and subsequently was discovered as a faint X-ray source in a deep ROSAT pointing. The basis for the coronal emission is unknown, given the presumed lack of Dynamo action. However, the X-ray/C IV ratio of Gamma Dra falls on a continuum of values; extending from the active K0 ``Clump'' giants like Beta Ceti, down to the old red giant Alpha Boo (K1 III) in the depths of the ``coronal graveyard.'' GHRS/G140L reconnaissance of high-excitation FUV emissions (Si IV, C IV, and N V) can be conducted at sensitivity levels orders of magnitude better than possible prior to HST. Such a survey of single red giants would provide a unique perspective on the breadth of activity to the right of the L-H boundary. It also would record the fluoresced 4th-positive system of CO, a key tracer of thermal inhomogeneities in late-type atmospheres. Seven candidates fall in the magnitude range V < 3. Three--Beta UMi, Epsilon Sco, and Epsilon Crv--will be observed, consistent with the TAC allocation. ------------------------------------------------------------------------------------ 6551( 5) - 06/03/96 13:47 - [ 2] Observations Description ------------------------ The K giants, though bright, are too red to be acquired directly on Side 1 of the GHRS. We therefore will use an FOS-assisted acquisition: a 3x3 spatial scan utilizing the G270H disperser and the 1.0 aperture. Following the acquisition, a GHRS/G140L exposure of approximately 30 minutes will be obtained. It will be done as a WSCAN over the interval 1166--1765 A in four steps (of 104 A each); in essence a king-size FP-SPLIT. The bandpass covers all of the important high- excitation species and the prominent CO fluoresced bands. The exposure can reach a limiting 5-sigma C IV 1548 flux of about 3E-15 ergs/cm^2/s. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6551( 5) - 06/03/96 13:47 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD131873 STAR,K III- RA=14H 50M 42.35S +/- J2000 V = 17. V = +2.08+/-0.1 I,CORONA,WIND, 0.05S,DEC=74D 9' 19.8" +/- 1" B-V = +1.47+/-0.1 TYPE=K4III Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.008 0.012 0.031 2 HD151680 STAR,K III- RA=16H 50M 9.82S +/- 0.05S,DEC=- J2000 V = -3. V = +2.29+/-0.1 I,CORONA,WIND, 34D 17' 35.7" +/- 1" B-V = +1.14+/-0.1 TYPE=K2III Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.049 -0.255 0.049 3 HD105707 STAR,K III- RA=12H 10M 7.49S +/- 0.05S,DEC=- J2000 V = 5. V = +3.00+/-0.1 I,CORONA,WIND, 22D 37' 11.2" +/- 1" B-V = +1.33+/-0.1 TYPE=K2III Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.005 0.014 0.020 6551( 5) - 06/03/96 13:47 - [ 4] Visit: 01 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 HD131873 FOS/BL ACQ/PEA 1.0 G270H SEARCH-SIZE-X=3,SCAN-STEP-X=0.8, 1 1.0 S ONBOARD ACQ FOR 2 K SEARCH-SIZE-Y=3,SCAN-STEP-Y=0.8, TYPE=UP ------------------------------------------------------------------------------------------------------------------------------------ 2 HD131873 HRS WSCAN 2.0 G140L 1256-16 COMB=FOUR,STEP-PATT=DEF, 1 1740.8 72 DOPPLER=DEF,FP-SPLIT=NO, WAVE-STEP=104 ------------------------------------------------------------------------------------------------------------------------------------ 6551( 5) - 06/03/96 13:47 - [ 5] 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 HD151680 FOS/BL ACQ/PEA 1.0 G270H SEARCH-SIZE-X=3,SCAN-STEP-X=0.8, 1 1.0 S ONBOARD ACQ FOR 2 K SEARCH-SIZE-Y=3,SCAN-STEP-Y=0.8, TYPE=UP ------------------------------------------------------------------------------------------------------------------------------------ 2 HD151680 HRS WSCAN 2.0 G140L 1256-16 COMB=FOUR,STEP-PATT=DEF, 1 1523.2 72 DOPPLER=DEF,FP-SPLIT=NO, WAVE-STEP=104 ------------------------------------------------------------------------------------------------------------------------------------ 6551( 5) - 06/03/96 13:47 - [ 6] Visit: 03 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 HD105707 FOS/BL ACQ/PEA 1.0 G270H SEARCH-SIZE-X=3,SCAN-STEP-X=0.8, 1 1.0 S ONBOARD ACQ FOR 2 K SEARCH-SIZE-Y=3,SCAN-STEP-Y=0.8, TYPE=UP ------------------------------------------------------------------------------------------------------------------------------------ 2 HD105707 HRS WSCAN 2.0 G140L 1256-16 COMB=FOUR,STEP-PATT=DEF, 1 1414.4 72 DOPPLER=DEF,FP-SPLIT=NO, WAVE-STEP=104 ------------------------------------------------------------------------------------------------------------------------------------ 6551( 5) - 06/03/96 13:47 - [ 7] Summary Form for Proposal 6551 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK WSCAN ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X=3 SCAN-STEP-X=0.8 SEARCH-SIZE-Y=3 SCAN-STEP-Y=0.8 TYPE=UP WAVE-STEP=104 FP-SPLIT=NO DOPPLER=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G270H G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD131873 HD151680 HD105707 ------------------------------------------------------------------------------------------------------------------------------------