16232( 4) - 18-Dec-2020 21:52:44 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16232 Version: 4 Check-in Time: 18-Dec-2020 21:52:44 STScI Edit Number: 0 Title Investigating The Interstellar Bullet Engine IRAS05506+2414 ------------------------------------------------------------------------------------ Type Cycle GO 28 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Raghvendra Sahai Jet Propulsion Laboratory Y CoI: Dr. Mark Claussen Associated Universities, Inc. N CoI: Dr. Mark R. Morris University of California - Los Angeles N CoI: Dr. Carmen Sanchez Contreras Centro de Astrobiologia (CSIC/INTA) Inst. N Nac. de Tec. Aero. CoI: Dr. Nimesh Patel Harvard University N CoI: Dr. Chin-Fei Lee Academia Sinica, Institute of Astronomy N and Astrophysics CoI: Prof. John Bally University of Colorado at Boulder N ------------------------------------------------------------------------------------ Abstract An exciting development in the understanding of the early evolutionary stages of massive stars, based on a new study of the Orion BN/KL region, is that the disruption of a massive young stellar system can lead to an explosive event producing a wide-angle outflow - an entirely different phenomenon from the classical bipolar flows driven by YSO accretion disks. We have discovered an object, IRAS05506+2414, which may be the 2nd clear-cut example of this phenomenon. Our HST optical and near-IR images show a fan-like spray of high-velocity (up to 350 km/s) elongated knots which appear to emanate from a bright compact central source; we find that the physical properties (opening angle, outflow speeds, knot masses, Herbig-Haro-object like optical line emission) of the IRAS05506 wide-angle outflow are very similar to those seen in Orion. We propose to determine IRAS05506's distance from a measurement of the knot proper motions using WFC3 to obtain a 2nd epoch F606W image. Only then will we be able to robustly constrain the central star's luminosity and mass and the dynamical time-scale, mass, velocity, and kinetic energy distributions of its outflows -- needed to test possible mechanisms for the explosive disintegration model for such sources. Deep emission-line imaging with WFC3 will be used to probe the full size and structure of the bullet spray. We will use STIS to confirm the presence of a second outflow engine in IRAS05506: an intriguing linear feature that looks like a classical YSO collimated jet can be seen emanating from the central source, but only a long-slit spectrum of the line emission with sufficient angular resolution can confirm it to be a high-velocity jet. ------------------------------------------------------------------------------------ Observations Description ------------------------ \noindent$\bullet$ {\bf WFC3/UVIS} -- We will obtain a deep 2nd-epoch image of IRAS\, 05506 using WFC3/UVIS (since ACS/HRC is no longer functional), but with longer exposure times than the the 1st epoch (discovery) observations -- covering one orbit (in which the HRC was used with 2$\times$400\, s exposures). 16232( 4) - 18-Dec-2020 21:52:44 - [ 2] This observation will enable proper motion determination with an accuracy better than 15\, \kms$\times$(D/2.8\, kpc). The longer exposure time will enable a more accurate comparison with the WFC3 emission line imaging, which is needed in order to distinguish emission-line knots from dusty substructure. For the deep optical emission-line imaging needed to probe the full azimuthal and radial extent of the knotty outflow, we will use the WFC3/UVIS camera and the H$\alpha$+[NII] (F657N) filter. It is better suited for sampling the knots than ACS/WFC because of its smaller pixels (0.04${''}$ compared to 0.05${''}$ ). \noindent$\bullet$ {\bf WFC3/IR} -- We will carry out high S/N imaging with WFC3/IR in the [FeII]\, 1.64\micron~emission-line and related continuum filters (F164N, F167N) in order to look for high-velocity knots with shocked gas near the central source, where the extinction is high and therefore not well-probed by the optical emission-line imaging. Shock models (Hartigan et al.\, 2004) show that the [FeII]\, 1.64\micron~emission is comparable or stronger than the optical forbidden line emission (e.g. in [OI]6300) for a variety of shock conditions (shock velocity, preshock density and ionization fraction etc.). Hence, the average [FeII] 1.64\micron~brightness in knot $K1$ is expected to be about $9\times10^{-15}$ erg s$^{-1}$ cm$^2$ arcsec$^{-2}$. We will therefore use exposure times of about 15 minutes for each of the F164N\, \&\, F167N filters, allowing us to detect knots which are fainter by a factor $\gtrsim$5 than $K1$. We are requesting the F167N narrow filter for continuum subtraction, because using the broad-band filter (see below) for subtraction in a region of large and variable extinction gives very poor results. We will use the F110W and F160W filters to distinguish faints stars from compact knots seen in the [FeII]\, 1.64\micron~image. Integration times of about 200 and 80\, s with WFC3 provide S/N of about 40 each in the F110W and F160W images. This high S/N will also improve the characterisation of many faint filamentary structures seen in the vicinity of the central source. \noindent$\bullet$ {\bf STIS} -- We will use STIS with G750M and the 52''$\times$0\farcs1 slit to obtain spectra in the $\lambda\lambda$6295-6867{\AA} range with $\sim$50\, \kms~spectral and 0.05 arcsec spatial resolution. The slit will be aligned along the jet, i.e. PA=238\arcdeg. We will thus cover the H$\alpha$, [NII]\, 6548, 6583 and [SII]\, 6717, 6731 lines; the [OI]6300 line will be near the edge, but still visible. The jet {\it Sa-jet(?)} is roughly 0.05 arcsec wide and about 0.2 arcsec long in the F606W ACS image. The H$\alpha$ average line intensity is 4.8$\times10^{-15}$ erg s$^{-1}$ cm$^2$ arcsec$^{-2}$ over a velocity width of about 130\, \kms, and a factor of 3.5 larger at the peak. The [SII]\, 6717, 6731 lines are 61\%, \, 94\% of the H$\alpha$ brightness. We will need an exposure time of about 70 minutes (i.e. 2 orbits) which gives us a S/N$\gsim$12 at the peak, and about 5 at a velocity offset of 130\, \kms. This S/N ratio is adequate to allow us to centroid the line peak to significantly better than 10\, \kms. From the observed PA of {\it Sa-jet(?)}, 50\arcdeg, we compute an $ORIENT=PA+46.3\arcdeg\sim96\arcdeg$ or $PA+226.3\arcdeg\sim276\arcdeg$ (as per the STIS handbook). We therefore request a slit ORIENT in the range 92\arcdeg--100\arcdeg, or 272\arcdeg-280\arcdeg, in order to probe the emission from the highly-collimated jet precisely. This ORIENT range, although restricted, allows many available windows for scheduling. We have also checked 16232( 4) - 18-Dec-2020 21:52:44 - [ 3] with the Help desk that we can use $Sa$ for registering the slit. Several brighter stars are also available for offset imaging, if in case during Phase II, we determine that the latter is the better option. We will use the STScI recommended dithering patterns for all data taken with the WFC3 and STIS in order to optimally sample the PSF. ------------------------------------------------------------------------------------ 16232( 4) - 18-Dec-2020 21:52:44 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 IRAS05506+24 ISM, REFLECTION NEBULA RA=05H53M43.5600S +/- 0.1", J2000 V = 15.4 +/- 1.0 R=15.4 14 DEC=+24D14'44.70" +/- 0.1" Reference Frame: ICRS Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 0.0 0 0 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 N30120321186 STAR, G V-IV RA=05H53M41.1932S +/- 0.001", J2000 V = 14.638 +/- 0.1 Rmag=13.7 DEC=+24D14'41.79" +/- 0.001" Reference Frame: ICRS Extended: NO Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2015.5 4.2121888864957136E-4 0.001267 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 16232( 4) - 18-Dec-2020 21:52:44 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.145 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 46.84 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-UVIS-DITHER-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.173 Line_Spacing 0.112 Coordinate_Frame POS-TARG Pattern_Orient 23.884 Angle_Between_Sides 81.785 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type WFC3-IR-DITHER-LINE Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 0.636 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 41.788 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 16232( 4) - 18-Dec-2020 21:52:44 - [ 6] Visit: 03 Visit Requirements: ORIENT 92D TO 100 D; ORIENT 272D TO 280 D 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 N3012032118 STIS/CCD ACQ 50CCD MIRROR 1 1 S (1 S) 6 ------------------------------------------------------------------------------------------------------------------------------------ 2 IRAS05506+2 STIS/CCD ACQ/PEA 52X0.1 MIRROR 1 30 S (30 414 K S) ------------------------------------------------------------------------------------------------------------------------------------ 3 IRAS05506+2 STIS/CCD ACCUM 52X0.1 G750M 6581 CR-SPLIT=4 1 2400 S 414 see below (4160 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ N30120321186 1 STIS/CCD ACQ 50CCD MIRROR none none none none 1 N/A IRAS05506+2414 2 STIS/CCD ACQ/PEA 52X0.1 MIRROR none none none none 1 N/A K IRAS05506+2414 3 STIS/CCD ACCUM 52X0.1 G750M 6581 none none none 1 1 786.0 S IRAS05506+2414 3 STIS/CCD ACCUM 52X0.1 G750M 6581 none none none 2 1 786.0 S IRAS05506+2414 3 STIS/CCD ACCUM 52X0.1 G750M 6581 none none none 3 2 1294.0 S IRAS05506+2414 3 STIS/CCD ACCUM 52X0.1 G750M 6581 none none none 4 2 1294.0 S 16232( 4) - 18-Dec-2020 21:52:44 - [ 7] Visit: 04 Visit Requirements: 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| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IRAS05506+2 WFC3/UVI ACCUM UVIS1-2K2 F657N FLASH=18 1 500 S PATTERN 3 1-2 414 S A-SUB (2000 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 IRAS05506+2 WFC3/UVI ACCUM UVIS1-2K2 F606W FLASH=14 1 100 S (400 414 S A-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 3 IRAS05506+2 WFC3/UVI ACCUM UVIS1-2K2 F606W FLASH=14 1 150 S (300 PATTERN 1 3 414 S A-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 4 IRAS05506+2 WFC3/UVI ACCUM UVIS1-2K2 F606W FLASH=18 1 45 S (180 PATTERN 3 4 414 S A-SUB S) ------------------------------------------------------------------------------------------------------------------------------------ 5 IRAS05506+2 WFC3/IR MULTIAC IR-FIX F167N NSAMP=10, SAMP-SEQ=STEP100 1 DEF PATTERN 2 5-8 414 CUM (798.463 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 IRAS05506+2 WFC3/IR MULTIAC IR-FIX F164N NSAMP=10, SAMP-SEQ=STEP100 1 DEF 414 CUM (798.463 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 IRAS05506+2 WFC3/IR MULTIAC IR-FIX F160W SAMP-SEQ=STEP100, NSAMP=8 1 DEF 414 CUM (398.462 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 IRAS05506+2 WFC3/IR MULTIAC IR-FIX F110W SAMP-SEQ=STEP100, NSAMP=8 1 DEF 414 CUM (398.462 S) ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ IRAS05506+2414 1 WFC3/UVI ACCUM UVIS1-2K F657N 1 none none none 1 N/A S 2A-SUB IRAS05506+2414 1 WFC3/UVI ACCUM UVIS1-2K F657N 2 none none none 1 N/A S 2A-SUB IRAS05506+2414 1 WFC3/UVI ACCUM UVIS1-2K F657N 3 none none none 1 N/A S 2A-SUB IRAS05506+2414 1 WFC3/UVI ACCUM UVIS1-2K F657N 4 none none none 2 N/A S 2A-SUB 16232( 4) - 18-Dec-2020 21:52:44 - [ 8] 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 | ------------------------------------------------------------------------------------------------------------------------------------ IRAS05506+2414 2 WFC3/UVI ACCUM UVIS1-2K F606W 1 none none none 1 N/A S 2A-SUB IRAS05506+2414 2 WFC3/UVI ACCUM UVIS1-2K F606W 2 none none none 1 N/A S 2A-SUB IRAS05506+2414 2 WFC3/UVI ACCUM UVIS1-2K F606W 3 none none none 2 N/A S 2A-SUB IRAS05506+2414 2 WFC3/UVI ACCUM UVIS1-2K F606W 4 none none none 2 N/A S 2A-SUB IRAS05506+2414 3 WFC3/UVI ACCUM UVIS1-2K F606W 1 none none none 2 N/A S 2A-SUB IRAS05506+2414 3 WFC3/UVI ACCUM UVIS1-2K F606W 2 none none none 2 N/A S 2A-SUB IRAS05506+2414 4 WFC3/UVI ACCUM UVIS1-2K F606W 1 none none none 2 N/A S 2A-SUB IRAS05506+2414 4 WFC3/UVI ACCUM UVIS1-2K F606W 2 none none none 2 N/A S 2A-SUB IRAS05506+2414 4 WFC3/UVI ACCUM UVIS1-2K F606W 3 none none none 2 N/A S 2A-SUB IRAS05506+2414 4 WFC3/UVI ACCUM UVIS1-2K F606W 4 none none none 2 N/A S 2A-SUB IRAS05506+2414 5 WFC3/IR MULTIAC IR-FIX F167N 1 none none none 3 N/A CUM IRAS05506+2414 5 WFC3/IR MULTIAC IR-FIX F167N 2 none none none 3 N/A CUM IRAS05506+2414 6 WFC3/IR MULTIAC IR-FIX F164N 1 none none none 3 N/A CUM IRAS05506+2414 6 WFC3/IR MULTIAC IR-FIX F164N 2 none none none 3 N/A CUM IRAS05506+2414 7 WFC3/IR MULTIAC IR-FIX F160W 1 none none none 3 N/A CUM IRAS05506+2414 7 WFC3/IR MULTIAC IR-FIX F160W 2 none none none 3 N/A CUM IRAS05506+2414 8 WFC3/IR MULTIAC IR-FIX F110W 1 none none none 3 N/A CUM IRAS05506+2414 8 WFC3/IR MULTIAC IR-FIX F110W 2 none none none 3 N/A CUM 16232( 4) - 18-Dec-2020 21:52:44 - [ 9] Summary Form for Proposal 16232 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 50CCD, 52X0.1, IR-FIX, UVIS1-2K2A-SUB ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, WFC3/IR, WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK, MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=4, FLASH=14, FLASH=18, NSAMP=10, NSAMP=8, SAMP-SEQ=STEP100 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 272D TO 280 D, ORIENT 92D TO 100 D, PATTERN 1 3, PATTERN 2 5-8, PATTERN 3 1-2, PATTERN 3 4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F110W, F160W, F164N, F167N, F606W, F657N, G750M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names IRAS05506+2414, N30120321186 ------------------------------------------------------------------------------------------------------------------------------------