6783( 9) - 10/29/96 12:19 - [ 0] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6783 Version: 9 Check-in Date: 29-Oct-1996 12:17:00 1.Proposal Title: ACTIVITY ON THE EDGE OF CONVECTION: THE ATMOSPHERE OF CANOPUS (F0 Ib-II) ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COOL STARS GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Alexander Brown University of Colorado CoI: Stephen Skinner University of Colorado N CoI: Tom Ayres University of Colorado N CoI: Brian Wood University of Colorado N ------------------------------------------------------------------------------------ 6. Abstract We propose GHRS observations of Canopus (Alpha Car), the nearest (40 pc) supergiant star. Canopus is an early F supergiant with a extremely thin convection zone, yet it shows significant X-ray emission from a very hot corona. UV chromospheric and transition (TR) region emission line fluxes will be used to determine the emission measure (EM) distribution and radiative losses from these regions, while the nonthermal turbulent motions in the TR will be measured from the emission profiles. EUVE and ASCA coronal spectroscopy are also being sought and will allow the coronal temperature and EM distributions to be established. In conjuction with similar data for Beta Dra (G2 Ib-IIa) we shall investigate how the TR turbulent energy relates to the observed coronal energy input for supergiants with differing convection zone depths. ------------------------------------------------------------------------------------ Observations Description ------------------------ Canopus will be acquired with Mirror A1 and all spectra obtained using GHRS Side 1 gratings. The G140L exposure will provide a complete spectrum of the accessible UV emission lines of Canopus and allow accurate flux measurement for all available emission lines. The Echelle-A spectrum will give a high resolution H I Ly-Alpha profile suitable for radiative transfer modelling and for determination of the interstellar N_H column density, a quantity of great importance for the analysis of the coronal spectroscopy. The G140M spectra will measure the emission line profiles for the strongest TR emission lines available. The O I spectra will show the presence of any cool wind outflow. Exposure times and expected signal-to-noise (S/N) levels have been estimated by extrapolation from the observed emission levels of Beta Dra. The observed X-ray flux for Canopus is 1.7 times larger than that of Beta Dra (Maggio et al 1990). Using the scaling laws of Ayres et al. (1995), the TR emission fluxes should be a factor of 1.4 times brighter. In these estimates we have assumed that Canopus will have similar line widths to those measured by IUE and HST for Beta Dra. Very little increase in observing efficiency would result from the use of STIS for this project. The STIS and GHRS sensitivities are similar in the proposed spectral regions. Only 3 orbits are required with GHRS and even combining the G140M spectra into a single STIS exposure would have difficulty in saving one orbit. TABLE 1: Proposed Exposures -------------------------------------------- --------------------- Grating Spectral Exposure S/N Diagnostic Features Range Time (A) (s) ----------------------------------------------------------------- ECH-A 1212-1218 1197 35 H I Ly-Alpha, ISM N_H G140L 1160-1446 544 100 Overall spectrum + line fluxes G140M 1198-1224 870 20 Si III UV 2 (1206 A), O V (1218 A) G140M 1227-1253 870 23 N V UV 1 G140M 1289-1314 870 30 O I UV 2 G140M 1331- 1357 870 26 C II UV 1, O I UV 1 ----------------------------------------------- ------------------ Real Time Justification ----------------------- There are no special restrictions on these observations. STScI may wish to note that Canopus lies very close to the CVZ at certain times of year, which may allow for more efficient scheduling. We are conducting a coordinated study of the outer atmosphere of Canopus involving HST, ASCA, and EUVE. The ASCA/EUVE observations will provide spectroscopy that will allow the coronal temperature and emission measure distribution to be determined. In addition, coronal elemental abundances should be obtainable. NB These observations do not require coordinated scheduling. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Center for Astrophysics and Space Astronomy,*Campus Box 389,*Boulder, CO 80309-0893 Ship Via: UPS Email: PI_Address , ------------------------------------------------------------------------------------ 6783( 9) - 10/29/96 12:19 - [ 1] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD45348 STAR, F0-F2 RA=06H 23M 57.119S +/- 0.01S, 2000 V = V = -0.72+/-0.01 DEC=-52D 41' 44.50" +/- 0.03" +20.5 B-V = +0.16+/-0.01 TYPE=F0I Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0024 0.021 0.025 6783( 9) - 10/29/96 12:19 - [ 2] 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 HD45348 HRS ACQ 2.0 MIRROR-N1 BRIGHT=RETURN,SEARCH-SIZE=3 1 1.8 S ONBOARD ACQ FOR 3 Comments: STEP-TIME = 0.2 SEC (approx 100,000 cts in STEP-TIME) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD45348 HRS IMAGE 2.0 MIRROR-A1 1 51.2 S Comments: STEP-TIME = 0.2 SEC (approx 500,000 cts in STEP-TIME) ------------------------------------------------------------------------------------------------------------------------------------ 3 HD45348 HRS ACQ/PEA 0.25 MIRROR-A1 SEARCH-SIZE=5 1 5 S ONBOARD ACQ FOR 10-55 KUP Comments: STEP-TIME = 0.2 SEC ------------------------------------------------------------------------------------------------------------------------------------ 10 HD45348 HRS ACCUM 0.25 ECH-A 1216.0 COMB=FOUR,STEP-PATT=DEF, 1 1196.8 DOPPLER=DEF,FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 15 HD45348 HRS ACCUM 2.0 G140L 1312.0 COMB=FOUR,STEP-PATT=DEF, 1 544.0 S DOPPLER=DEF,FP-SPLIT=DSTWO ------------------------------------------------------------------------------------------------------------------------------------ 25 HD45348 HRS ACCUM 2.0 G140M 1210.0 COMB=FOUR,STEP-PATT=DEF, 1 870.4 S DOPPLER=DEF,FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 35 HD45348 HRS ACCUM 2.0 G140M 1242.0 COMB=FOUR,STEP-PATT=DEF, 1 870.4 S DOPPLER=DEF,FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 45 HD45348 HRS ACCUM 2.0 G140M 1299.0 COMB=FOUR,STEP-PATT=DEF, 1 870.4 S DOPPLER=DEF,FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 55 HD45348 HRS ACCUM 2.0 G140M 1344.0 COMB=FOUR,STEP-PATT=DEF, 1 870.4 S DOPPLER=DEF,FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 6783( 9) - 10/29/96 12:19 - [ 3] Summary Form for Proposal 6783 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ IMAGE ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 SEARCH-SIZE=5 FP-SPLIT=STD FP-SPLIT=DSTWO DOPPLER=DEF STEP-PATT=DEF COMB=FOUR ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 3 ONBOARD ACQ FOR 10-55 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 MIRROR-A1 ECH-A G140L G140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD45348 ------------------------------------------------------------------------------------------------------------------------------------