9965( 13) - 02/10/04 13:29 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9965 Version: 13 Check-in Date: 10-Feb-2004 13:27:13 1.Proposal Title: Expansion distances to the symbiotic Miras He 2-104 and He 2-147 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Romano L.M. Corradi Isaac Newton Group of Telescopes CoI: Prof. Ulisse Munari Padova and Asiago Astronomical N Observatories CoI: Dr. Francesca R. Boffi Space Telescope Science Institute N CoI: Dr. Mario Livio Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract We propose to measure the expansion parallax of the nebulae around the binary symbiotic Miras He 2-104 (the Southern Crab) and He 2-147 by means of high resolution WFPC2/F658N images to be taken at two different epochs. Given the large outward velocities of these nebulae inferred from ground-based spectroscopy, their apparent expansion can be measured by HST imaging over timescales of only 2-3 years. Combining the angular and radial velocity expansions will straightforwardly yield the distance to the proposed targets. Knowledge of the distance to these nebulae will provide a solid contribution to a variety of research fields such as (a) the energetics of nuclear burning in symbiotic binaries containing a Mira, (b) the pulsation mode of binary Miras, and (c) the viability of Mira symbiotics as supersoft X-ray sources and potential progenitors of Type Ia supernovae. HST high resolution imaging of the nebulae combined with ground-based spectroscopy will also address the still debated issue of the formation of bipolar nebulae by collimated outflows from evolved stars. ------------------------------------------------------------------------------------ 9965( 13) - 02/10/04 13:29 - [ 2] Observations Description ------------------------ We propose to observe He 2-104 and He 2-147 in the light of N II 6583 Angstrom with the WFPC2 camera. Observing in the N II line has the following advantages: i) N II6583 is the brightest line in the extended nebulae of all symbiotic Miras in the range 350-1200 nm; ii) the contrast in luminosity between the central source and the much fainter extended nebula is strongly reduced as compared, for instance, to H-alpha, limiting the oversaturation of the unresolved central source. Excellent results have been already obtained with HST NII imaging for He 2-104 on May 1999 and on May 2003. 'Epoch 1' HST [NII] images of He 2-147 have also been obtained on September 2001, and we plan now to take `Epoch 2' images during cycle 12 (>=3 yr later). To allow for precise comparison of images in different epochs, the same centering on the PC camera, ORIENT parameter, and exposure times will be used. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9965( 13) - 02/10/04 13:29 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PK327-04D1 STAR, SYMBIOTIC STAR, RA=16H14M1.0S +/- 0.2S, DEC=- J2000 V = 0.0 V = 15.0+/-0.5 EMISSION LINE NEBULA, 56D59'26.8" +/- 0.2", PLATE- F-LINE(6583)=3+/-2e-13 EJECTA, AGB STAR, NOVA- ID=06PU LIKE Coordinate Source: GSC_SURVEY_PLATE Comments: Ring-like nebula 9965( 13) - 02/10/04 13:29 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFPC2-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.56505 Center_Pattern YES ------------------------------------------------------------------------------------------------------------------------------------ 9965( 13) - 02/10/04 13:29 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 119.0D TO 119.0 D; AFTER 01-MAY-2004:00:00:00 On Hold Comments: Additional Comments: The ORIENT angle is fixed so as to match the observations in 2001. SCHEDULE THE VISIT AFTER APPROX MID 2004 (THE VISIBILITY WINDOWS DURING 2003 AND EARLY 2004 SHOULD BE REJECTED), IN ORDER TO ALLOW A TIME LAPSE >3 YR BETWEEN EPOCH 1 AND 2 IMAGES. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PK327-04D1 WFPC2 IMAGE PC1-FIX F658N ATD-GAIN=15 1 140 S POS TARG 0, 0; PATTERN 1 1-2 ------------------------------------------------------------------------------------------------------------------------------------ 2 PK327-04D1 WFPC2 IMAGE PC1-FIX F658N ATD-GAIN=15 2 400 S POS TARG 0, 0 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 01 1 1 none none none 1 tbd 01 1 2 none none none 1 tbd 01 1 3 none none none 2 tbd 01 1 4 none none none 2 tbd 01 2 1 none 1 none 1 tbd 01 2 1 none 2 none 1 tbd 01 2 2 none 1 none 1 tbd 01 2 2 none 2 none 1 tbd 01 2 3 none 1 none 2 tbd 01 2 3 none 2 none 2 tbd 01 2 4 none 1 none 2 tbd 01 2 4 none 2 none 2 tbd 9965( 13) - 02/10/04 13:29 - [ 6] Summary Form for Proposal 9965 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN=15 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 119.0D TO 119.0 D; AFTER 01-MAY-2004 00 00 00 POS TARG 0, 0; PATTERN 1 1-2 POS TARG 0, 0 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F658N ------------------------------------------------------------------------------------------------------------------------------------ Target Names PK327-04D1 ------------------------------------------------------------------------------------------------------------------------------------