11224( 4) - 07/06/07 13:51 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11224 Version: 4 Check-in Time: 06-Jul-2007 17:51:27 STScI Edit Number: 0 Title Unraveling Mira AB Accretion Mysteries ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Margarita Karovska Smithsonian Institution Astrophysical Observatory CoI: Dr. John C. Raymond Smithsonian Institution Astrophysical N Observatory CoI: Mr. Warren Hack Space Telescope Science Institute N CoI: Dr. Brian E. Wood University of Colorado at Boulder N CoI: Dr. Danny Steeghs Smithsonian Institution Astrophysical N Observatory ------------------------------------------------------------------------------------ Abstract Wind accretion is one of the most common yet poorly understood phenomena in astrophysics. A key step toward advancing our understanding of physical processes and accretion geometries in wind accreting systems is direct imaging of the individual components and mass flows. The nearby symbiotic binary Mira AB, composed of an AGB donor star and an accreting compact companion, is a unique target since it can be easily spatially resolved with the HST, and thus serves as a perfect test laboratory for accretion studies in wind interacting systems. We propose to carry out WFPC2 observations of Mira AB following the HST and Chandra detections of an unprecedented outburst from the cool giant, and the discovery of an accretion stream showing for the first time evidence for a direct mass transfer between the components in a wind accreting system. High-angular-resolution multiwavelength imaging at UV /optical wavelengths will allow us to determine the properties of the ejected material as it flows throughout the binary and interacts with the Mira A circumstellar material and wind; the physical characteristics of mass transfer in this system and especially the role of the accretion stream between Mira A and Mira B; and the response of the system to the increased accretion rate onto Mira B following the outburst. These results will provide crucial inputs and quantitative constraints to models of wind interacting systems and will also anchor our understanding of accretion processes in a wide range of interacting binaries that cannot be currently resolved, including in other symbiotics and more exotic systems such as accreting black holes and neutron stars in high-mass X-ray binaries. ------------------------------------------------------------------------------------ 11224( 4) - 07/06/07 13:51 - [ 2] Observations Description ------------------------ These observations will investigate the interaction between Mira A and B using multi-spectral imaging with the WFPC2 PC. We plan to carry out WFPC2 high- angular resolution imaging (0.046"/pixel) of Mira AB, using the dither mode in several filters. This would allow us to unambiguously study the components of the system (and the changes that have occurred since the last HST observation in 2004), including the ejected material, and the accretion stream between MiraA and MiraB. We propose to carry out the observations during the last quarter of 2007 when MiraA is expected to be fainter than 8.5 magnitudes (based on AAVSOLPV predictions the MiraA optical minimum, V<9.5 magnitude, is expected in November 2007). This will allow imaging with WFPC2 and will increase the contrast of different emitting components in the system, including the mass flow between the components and the region of interaction between the ejecta and the circumbinary material. MiraB itself is expected to be fainter than V=10 magnitude. We have selected a set of filters to separate line and continuum emission, to distinguish shocked from photoionized gas, and to determine the shock speed or the nature of the photoionizing continuum. For example, the H- alpha, [OII] 3729A, and [OIII]5007A lines are bright, and they provide information on the ionization state of the gas. The [SII] 6731A/ H-alpha ratio will allow us to identify shocked vs. ionized gas emission, e.g., the ratio will be ~0.4 for shocked gas, and smaller for photoionized gas. Further diagnostics will be provided using the [NeV] 3426A line, e.g. the [NeV] line appears only at shock speeds above 150km/s. The O[III]4363A/5007A ratio gives the temperature which further constrains either the shock speed or the ionizing spectrum. We selected 9 filters covering the line and continuum emission. 6 of them are centered on emission lines, e.g. F344N[NeV], F375N[OII], F437N & F502N[OIII], F656NH, F673N[SiII]. We will compare our narrow-band images with continuum images obtained using the F160BW, F336W, F547M filters. The dithered observations will be taken using all filters at each dither position before moving to the next position in order to minimize the overheads. Additional longer exposures for a couple of key filters will then be taken at the end of the dithered exposures in order to provide increased S/N for all components of the MiraAB system. We note that in 2004 MiraB was ~0.55" away from MiraA at a PA ~110deg. (GO- 5822; GO-8298; GO-10091), and we had no trouble acquiring the targets and obtaining spectroscopy. Because of the long orbital period (>400yrs) we do not expect that Mira-B has moved much since February 2004. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 11224( 4) - 07/06/07 13:51 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 MIRAAB STAR, INTERACTING RA=02H19M20.7900S +/- 0.1", J2000 V = 8.0+/-1.0 BINARY, LOW MASS DEC=-02D58'39.50" +/- 0.1" COMPANION, M III-I, LONG PERIOD VARIABLE, Reference Frame: ICRS 11224( 4) - 07/06/07 13:51 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFPC2-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.559017 Line_Spacing 0.559017 Coordinate_Frame POS-TARG Pattern_Orient 26.56505 Angle_Between_Sides 143.130102 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 11224( 4) - 07/06/07 13:51 - [ 5] Visit: 01 Visit Priority: Visit Requirements: BETWEEN 01-SEP-2007:21:00:05 AND 30-DEC-2007:21:00:05 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 MIRAAB WFPC2 IMAGE PC1-FIX F160BW 1 2 S POS TARG -5,-5; PATTERN 1 1-9 ------------------------------------------------------------------------------------------------------------------------------------ 2 MIRAAB WFPC2 IMAGE PC1-FIX F336W 1 2 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 3 MIRAAB WFPC2 IMAGE PC1-FIX F547M 1 0.11 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 4 MIRAAB WFPC2 IMAGE PC1-FIX F343N 1 60 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 5 MIRAAB WFPC2 IMAGE PC1-FIX F375N 1 30 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 6 MIRAAB WFPC2 IMAGE PC1-FIX F437N 1 10 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 7 MIRAAB WFPC2 IMAGE PC1-FIX F656N 1 1 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 8 MIRAAB WFPC2 IMAGE PC1-FIX F673N 1 1 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 9 MIRAAB WFPC2 IMAGE PC1-FIX F502N 1 2 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 10 MIRAAB WFPC2 IMAGE PC1-FIX F502N 1 10 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ 11 MIRAAB WFPC2 IMAGE PC1-FIX F375N 1 200 S POS TARG -5,-5 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MIRAAB 1 WFPC2 IMAGE PC1-FIX F160BW 1 none none none 1 N/A MIRAAB 1 WFPC2 IMAGE PC1-FIX F160BW 2 none none none 1 N/A MIRAAB 1 WFPC2 IMAGE PC1-FIX F160BW 3 none none none 2 N/A MIRAAB 1 WFPC2 IMAGE PC1-FIX F160BW 4 none none none 3 N/A MIRAAB 2 WFPC2 IMAGE PC1-FIX F336W 1 none none none 1 N/A MIRAAB 2 WFPC2 IMAGE PC1-FIX F336W 2 none none none 1 N/A MIRAAB 2 WFPC2 IMAGE PC1-FIX F336W 3 none none none 2 N/A MIRAAB 2 WFPC2 IMAGE PC1-FIX F336W 4 none none none 3 N/A MIRAAB 3 WFPC2 IMAGE PC1-FIX F547M 1 none none none 1 N/A MIRAAB 3 WFPC2 IMAGE PC1-FIX F547M 2 none none none 1 N/A MIRAAB 3 WFPC2 IMAGE PC1-FIX F547M 3 none none none 2 N/A MIRAAB 3 WFPC2 IMAGE PC1-FIX F547M 4 none none none 3 N/A 11224( 4) - 07/06/07 13:51 - [ 6] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ MIRAAB 4 WFPC2 IMAGE PC1-FIX F343N 1 none none none 1 N/A MIRAAB 4 WFPC2 IMAGE PC1-FIX F343N 2 none none none 1 N/A MIRAAB 4 WFPC2 IMAGE PC1-FIX F343N 3 none none none 2 N/A MIRAAB 4 WFPC2 IMAGE PC1-FIX F343N 4 none none none 3 N/A MIRAAB 5 WFPC2 IMAGE PC1-FIX F375N 1 none none none 1 N/A MIRAAB 5 WFPC2 IMAGE PC1-FIX F375N 2 none none none 2 N/A MIRAAB 5 WFPC2 IMAGE PC1-FIX F375N 3 none none none 2 N/A MIRAAB 5 WFPC2 IMAGE PC1-FIX F375N 4 none none none 3 N/A MIRAAB 6 WFPC2 IMAGE PC1-FIX F437N 1 none none none 1 N/A MIRAAB 6 WFPC2 IMAGE PC1-FIX F437N 2 none none none 2 N/A MIRAAB 6 WFPC2 IMAGE PC1-FIX F437N 3 none none none 2 N/A MIRAAB 6 WFPC2 IMAGE PC1-FIX F437N 4 none none none 3 N/A MIRAAB 7 WFPC2 IMAGE PC1-FIX F656N 1 none none none 1 N/A MIRAAB 7 WFPC2 IMAGE PC1-FIX F656N 2 none none none 2 N/A MIRAAB 7 WFPC2 IMAGE PC1-FIX F656N 3 none none none 2 N/A MIRAAB 7 WFPC2 IMAGE PC1-FIX F656N 4 none none none 3 N/A MIRAAB 8 WFPC2 IMAGE PC1-FIX F673N 1 none none none 1 N/A MIRAAB 8 WFPC2 IMAGE PC1-FIX F673N 2 none none none 2 N/A MIRAAB 8 WFPC2 IMAGE PC1-FIX F673N 3 none none none 2 N/A MIRAAB 8 WFPC2 IMAGE PC1-FIX F673N 4 none none none 3 N/A MIRAAB 9 WFPC2 IMAGE PC1-FIX F502N 1 none none none 1 N/A MIRAAB 9 WFPC2 IMAGE PC1-FIX F502N 2 none none none 2 N/A MIRAAB 9 WFPC2 IMAGE PC1-FIX F502N 3 none none none 3 N/A MIRAAB 9 WFPC2 IMAGE PC1-FIX F502N 4 none none none 3 N/A MIRAAB 10 WFPC2 IMAGE PC1-FIX F502N none none none none 3 N/A MIRAAB 11 WFPC2 IMAGE PC1-FIX F375N none none none none 3 N/A 11224( 4) - 07/06/07 13:51 - [ 7] Summary Form for Proposal 11224 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 01-SEP-2007 21 00 05 AND 30-DEC-2007 21 00 05; POS TARG -5,-5; PATTERN 1 1-9; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F160BW F336W F547M F343N F375N F437N F656N F673N F502N ------------------------------------------------------------------------------------------------------------------------------------ Target Names MIRAAB ------------------------------------------------------------------------------------------------------------------------------------