Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1197c Report Date: 09-May-96:16:18 Version: ********** Check-in Date: ********** 1.Proposal Title: FOC OBSERVATIONS OF THE EXTENDED CHROMOSPHERE OF ALPHA SCO A ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GTO/HRS Sub Category COOL STARS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Kenneth G. Carpenter NASA - GODDARD SPACE FLIGHT USA 301-286-3453 ASTROPHYSICIST ------------------------------------------------------------------------------------ 7. Abstract The aim of this proposal is to obtain direct imaging of the extended chromosphere/stellar wind of the cool supergiant star Alpha Sco A, using the FOC/288 mode in the ultraviolet. The spatial properties, such as asymmetric mass loss and the radial variation of density and temperature, of the wind will be investigated. We also hope to detect and study the ionization/shock front between this stellar wind and that from the companion B-star. The 0.4 arcsec coronographic finger will be used to block the disk of the B-star and prevent an overexposure of the FOC. ------------------------------------------------------------------------------------ 8. Scientific Key Words: COOL STARS: CHROMOSPHERES, WINDS, MASS LOSS; INTERACTING BINARIES. ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1197c PI: Kenneth G. Carpenter Proposal Title: FOC OBSERVATIONS OF THE EXTENDED CHROMOSPHERE OF ALPHA SCO A ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Alexander Brown COLORADO, UNIVERSITY OF USA Jeffrey L. Linsky COLORADO, UNIVERSITY OF USA Kenneth G. Carpenter NASA - GODDARD SPACE FLIGHT USA CENTER ------------------------------------------------------------------------------------ 3. Description of proposed observations. SUMMARY OF FOC OBSERVATIONS Target = Alpha Sco A We plan to obtain FOC image in the f/288 mode, in the light of selected chromospheric emission lines, as indicated below: PRIMARY LINES in Exposure times (minutes) in net bandpass 512x512 format 256x256 format C II 2325 A 10 3 Fe II 2500 A 5 4 Mg II 2800 A 6 3 Continuum 3300 A - 10 An interactive target acquisition will be performed to ensure that the B-star companion is place behind the occulting finger (0.4") before these observations are obtained. The continuum observation is designed to detect any light produced by scattering off of dust particles in the wind. The complicated filter selections (i.e. multiple filters in each observation) listed on the exposure logsheets are needed to eliminate possible overexposure due to the visual light leaks that occur with single filters. Total time on cover page = 42 min exposing + 18 min overhead = 60 min total To be done in cycle 2 with priority 2 Comment from EL page 10: We wish to review orientation and position info, and update them if necessary, shortly before these cycle 1 observations are actually scheduled. Info based on 272-degree A-to-B position angle and a 206-degree FOC-to-ST AXIS offset. Update (7/21/88): The FOC team (through Chris Blades) has indicated that the exact relationship (geometry) of the 0.4 occultation finger and the f/288 format is not known at this time and that precise positioning and orientation information cannot be given in this proposal until further data reduction by the FOC team has occurred. Furthermore, the handbook and Phase 2 instructions differ in their descriptions of the coordinate system and its relationship to the line scan and frame directions in the f/288 mode. Hence further updates to this proposal will be necessary after the FOC team has clarified the instructions and performed the necessary data reduction. The values assigned to the special requirements in the current version of the proposal are based on the information in the FOC handbook. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. This project requires very high spatial resolution at ultraviolet wavelengths. Clearly, therefore, satellite observations (ST) are required and the FOC is required since it is the only instrument capable of providing the needed spatial resolution. These observations test the FOC in its f/288 mode in a situation where photons should be plentiful. Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. These observations must be scheduled at a time when the 0.4 arsec coronographic finger of the FOC can be used to hide the B-star companion of Alpha Sco A to avoid overexposing the FOC when properly exposing for the wind emission of the cool supergiant. The real-time acquisition observation is needed to ensure that the B-star is behind the occulting finger before the primary observations are obtained (see section 8). Schedule HRS observations of Alpha Sco A (from proposal WINDS OF COOL LUMINOUS STARS No. 1195) as close as possible after the FOC observations described in this proposal to insure that the data from both instruments represents the same state of the chromosphere, and to allow an update on the HRS acquisition of Alpha Sco A based on the final FOC positioning. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The radial intensity variation of each emission line map will be used to derive the radial variation of density to first order since the flux of the permitted and intersystem lines to be observed vary to first order as Nedex2 and Ne, respectively. The decline of intensity will also be affected by any decrease in temperature and this can be studied by comparing the behavior of the different emission lines which all form preferentially at slightly different temperatures. The basis for such an analysis is already established from current chromospheric research. Typical electron densities in these regions are on the order of 10dex8 cm^-3 (Stencel et al. 1981 MNRAS 196, 478). The regions extend to at least 3 - 5 stellar radii and probably further, as supported by analysis of both UV emission lines such as the C II multiplet (see Carpenter, Brown, and Stencel 1985 Ap. J., 289,676) and radio continuum observations. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. We note once again that the 0.4 arcsec coronographic finger of the FOC must be used to avoid overexposing the FOC. The finger will be used to hide the B-star companion to Alpha Sco A. Note: Even though the B-star (Alpha Sco B) will be outside the area of the photocathode to be scanned during the requested IMAGE mode observations of Alpha Sco A, the finger is needed to prevent damage to the portion of the detector just outside the scanned area. The 2.9" separation of the 2 stars allows Alpha Sco B to occulted by the finger while Alpha Sco A is positioned near the center of the IMAGE mode field. Any necessary adjustment to the position of Alpha Sco A will be made during the interactive target acquisition. ------------------------------------------------------------------------------------ 13. FOC images, in the light of selected chromospheric emission lines, of the Alpha Sco A wind/chromosphere will be obtained. The spatial properties of the wind, such as asymmetric mass loss and the radial variation of density and temperature, will be investigated and the interaction between the winds of the cool supergiant and its companion B-star will be studied. ------------------------------------------------------------------------------------ 11. Address Information Name: KENNETH G. CARPENTER Category: PI Institution: NASA - GODDARD SPACE FLIGHT CENTE Address: CODE 681 City: GREENBELT State: MD Zip Code: 20771 Country: USA Telephone: 301-286-3453 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1197c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD148478 M1.5 IAB RA=16H26M20.206S+/-.05", 1950 V=-3 COMP 1 V=0.96+/-.3, ALPHA-SCO-A DEC=-26D19'21.95"+/-.05" Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 1950.00 -0.0005 +/- 0.0001 -0.0230 +/- 0.0010 0.0000 +/- 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1197c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD148478 FOC/ ACQ 512X102 F8ND, PIXEL=25X25 1 1M 3 1 2 CYCLE 2/1-8 288 4 F275W, INT ACQ FOR 2 - 8 F1ND ORIENT 118D +/- 1D /1-8 POS TARG 0,0/1-8 SEQ 2-8 Comments: ADDITIONAL FILTER F346M. GROUP 2-8 WITHIN INTERACTIVE ACQ WILL BE USED TO 1D VERIFY COMPANION B-STAR BEHIND OCCULTATION FINGER. EXPOSURES 2 -8 WILL BE OBTAINED IN IMAGE MODE, BUT COMPANION B-STAR TO BE KEPT BEHIND 0.4 ARSEC FINGER AT ALL ------------------------------------------------------------------------------------------------------------------------------------ 2 HD148478 FOC/ IMAGE 512X512 F4ND, 1 10M 9 2 SEQ 2 - 3 NO GAP 288 F220W, F231M Comments: TIMES. B-STAR WILL BE OUTSIDE OF ACTIVE FIELD OF VIEW BUT STILL ON THE DETECTOR (THUS FINGER IS REQUIRED). LISTED EXPOSURE TIMES BASED ON SUMMATION OF UV LINE FLUXES OVER BROAD WAVELENGTH REGIONS, CONVOLVED ------------------------------------------------------------------------------------------------------------------------------------ 3 ^ ^ ^ 256X256 F2ND, 1 3M 10 2 F220W, F231M Comments: WITH FILTER TRANSMISSIONS. THEREFORE WE CANNOT GIVE A SINGLE REFERENCE FLUX FOR EACH OBSERVATION. ***> SEE GEN. FORM SECTION 3 FOR NOTE ON ORIENTATION/POSITION SPEC'S. ------------------------------------------------------------------------------------------------------------------------------------ 4 HD148478 FOC/ IMAGE 256X256 F2ND, 1 4M 15 2 SEQ 4 - 5 NO GAP 288 F220W, F253M ------------------------------------------------------------------------------------------------------------------------------------ 5 ^ ^ ^ 512X512 F2ND, 1 5M 12 2 F220W, F1ND Comments: ADDITIONAL FILTER F253M ------------------------------------------------------------------------------------------------------------------------------------ 6 ^ ^ ^ 512X512 F6ND, ^ 6M 10 ^ SEQ 6 - 7 NO GAP F220W, F1ND Comments: ADDITIONAL FILTER F278M ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1197c [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 7 ^ ^ ^ 256X256 F4ND, ^ 3M 15 ^ F220W, F1ND Comments: ADDITIONAL FILTER F278M ------------------------------------------------------------------------------------------------------------------------------------ 8 ^ ^ ^ ^ F6ND, ^ 10M 10 ^ F275W, F1ND Comments: ADDITIONAL FILTER F346M ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1197c [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/288 ^ ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ IMAGE ^ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=25X25 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/HRS ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 2/1-8; INT ACQ FOR 2 - 8; ORIENT 118D +/- 1D/1-8; POS TARG 0,0/1-8; SEQ 2-8; GROUP 2-8 WITHIN 1D SEQ 2 - 3 NO GAP SEQ 4 - 5 NO GAP SEQ 6 - 7 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F8ND,F275W,F1ND F4ND,F220W,F231M F2ND,F220W,F231M F2ND,F220W,F253M F2ND,F220W,F1ND F6ND,F220W,F1ND F4ND,F220W,F1ND F6ND,F275W,F1ND ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD148478 ALPHA-SCO-A ------------------------------------------------------------------------------------------------------------------------------------