This target is not used in this proposal. This pattern is not used in this proposal. changed orient to 82 degrees to match previous epoch. 1479982519 ----- Attempting Submission 7 (Mon Dec 14 13:24:05 GMT 2015) ----- The HH 24 complex constitutes the richest concentration of collimated bright Herbig-Haro jets known, and they originate from a small grouping of newborn binary and multiple systems. At least 6 jets are identified in deep groundbased optical interference images, and a similar number of sources in infrared images. We propose to do the first HST study of this complex, using H-alpha and [SII] filters. HST 0.05" to 0.1" angular resolution (20 to 40 AU at d~400 pc) is needed to resolve the shocks and their post-shock cooling layers for comparison with advanced numerical modeling. Our emphasis here is to explore outflows from a multiple system of newborn stars. Many of the jets show clear evidence of wiggling. The theory of jet motion from binary systems coupled with disk precession is now understood, and we will interpret the jet wiggles in this framework. Additionally, two of the HH 24 jets are showing evidence for a collision, a unique situation not seen anywhere else, and HST resolution is needed for comparison with gas-dynamic studies of jet-jet collisions. Two of the HH 24 jets are bright in the infrared [FeII] 1.644 line. In this line the main jet can be traced all the way to the source, which is the most important region for understanding the effects of binarity on the jet structure. We also apply for a second-epoch [SII] image in Cycle 23. This allows us, in addition to deriving the bulk motion, to determine such processes as expansion of the jet beam, sideways ejection in a working surface, turbulent and chaotic motions, and the effect of instabilities. We have tried to determine absolute fluxes of knots in the HH 24 jet No.4 from our groundbased data. The main body of the jet ranges from 1.2x10-15 to 1.2x10-14 erg sec-1 cm-2 arcsec-2 in [SII] (this does not include the bright knot in the collision region, which is much brighter). For 0.04'' pixels the exposure time calculator for WFC3 indicates that we will get a S/N of 10 for exposure times ranging from 1900 sec to 26000 sec. The H-alpha emission has about the same range in fluxes (although distributed very differently from the [SII] knots). In both cases we are photon-limited, that is, out of the read noise. In the infrared [FeII] 1.644 micron line, we measure a flux in our groundbased images of 2x10-15 erg sec-1 cm-2 arcsec-2 in the brightest knot in the HH 24 jet No.4 (again not in the very bright collision zone at the end of the jet). The exposure time calculator indicates that we get a S/N of 10 in 478 sec. The jet fades steadily along its body by about a factor 100. Hence in practical terms the exposure time decides how far out along the jet that we can get meaningful results. In the first visit (2 orbits) we observe the HH 24 complex in H-alpha (F656N) with the standard 4 point dithering by WFC3/UVIS. The second visit (2 orbits) is the same as the first visit, but in [SII] (F673N). The third visit (2 orbits) observe [FeII] in the F164N filter using the WFC3/IR detector, and a total of 6 sequences with dithering are used. The pointing of the IR visit is slightly different from the H-alpha/[SII] visits in order to better focus on the jet No.4 lobes. We would like these 3 visits observed as close together as possible, not exceeding a month in interval. This is important due to the significant tangential motion of the objects, so the closer in time the visits can be made, the better. Besides the primary WFC3 observations, we have received permission (Request Number 74858) to execute coordinated parallel observations with ACS/WFC. These parallel observations are done in the H-alpha filter F658N for all orbits, and they target the objects HH 19/20/21, which are the working surfaces of the HH 24 jet. The HH 19/20/21 objects are very extended, and therefore are observable for a range of Orient Angle between 82 and 110 D. The ideal Orient would be between 82 and 96 D, but any angle up to 110D will be satisfactory, if needed for scheduling purposes. RESOLVED STAR FORMATION 12 false false false false 0.0 0.0 SUPPORTED ISM HERBIG-HARO OBJECT The HH 24 jet complex contains shocks with fluxes ranging over many orders of magnitude, from the brighest knots to weak diffuse emission. J2000 J2000 ISM HERBIG-HARO OBJECT The HH 24 jet complex contains shocks with fluxes ranging over many orders of magnitude, from the brighest knots to weak diffuse emission. J2000 J2000 WFC3/UVIS Imaging No No F656N WFC3/UVIS Imaging No No F673N WFC3/IR Imaging No No F164N POS-TARG DITHER 3.633 LINE 2.352 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false POS-TARG DITHER 0.572 LINE 0.365 false true 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false POS-TARG DITHER 0.45 LINE false false 2 131.788 WFC3-IR-DITHER-LINE 3 false 1436875735475 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. 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