This resubmission addresses the change of filter usage to account for the red-leak problem in F218W. This filter has been replaced by the F160BW filter after consultation with and approval from the I.S. for this program. Observing comments updated. ----- Attempting Submission 1 (Thu May 03 13:12:36 GMT 2007) ----- Phase II Proposal 11224 (Prop11224) successfully submitted. ----- Attempting Submission 2 (Fri Jul 06 13:28:36 GMT 2007) ----- ----- Attempting Submission 3 (Fri Jul 06 17:39:15 GMT 2007) ----- none Resubmission of ACS proposal that had ID number 329 Assigned ID: 1131 ----- Attempting Submission 1 (Wed Feb 07 22:22:12 GMT 2007) ----- Phase I Proposal 1131 (prop.5sub) successfully submitted. ----- Attempting Submission 2 (Thu Feb 08 00:31:03 GMT 2007) ----- Phase I Proposal 1131 (prop.5sub) successfully submitted. ----- Attempting Submission 3 (Thu Feb 08 17:35:17 GMT 2007) ----- Unraveling Mira AB Accretion Mysteries 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.
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. HOT STARS 12 false 0 0.0 0 false false false false false false SUPPORTED STAR INTERACTING BINARY LOW MASS COMPANION M III-I LONG PERIOD VARIABLE WIND J2000 02 19 20.7900 -02 58 39.50 J2000 WFPC2 Imaging No F218W WFPC2 Imaging No F336W WFPC2 Imaging No F343N WFPC2 Imaging No F375N WFPC2 Imaging No F375N WFPC2 Imaging No F437N WFPC2 Imaging No F502N WFPC2 Imaging No F547M WFPC2 Imaging No F656N WFPC2 Imaging No F673N WFPC2 Imaging No F502N WFPC2 Imaging No F656N POS-TARG DITHER 0.559017 LINE 0.559017 false false 143.130096 4 26.56505 WFPC2-BOX 1 false (Tic-Visit :proposal-id 11224 :visit-id "01" :proposal-version -1 :trans-version "20070326" :date "06-Jul-2007 09:28:13.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 3 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 1703008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11224 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11224 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2700 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11224 :visit-id "01" :orbit-number 2 :pcs-time 355 :si-vis-utilization 2640 :al-overhead-at-end 120 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11224 :visit-id "01" :orbit-number 3 :pcs-time 355 :si-vis-utilization 2760 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 3 0 C:\Documents and Settings\hack\Local Settings\Temp\OPVisit38230.xml