15209( 2) - 05-Dec-2018 20:54:14 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15209 Version: 2 Check-in Time: 05-Dec-2018 20:54:14 STScI Edit Number: 0 Title High-Speed Bullet Ejections during the AGB to Planetary Nebula Transition: A Study of the Carbon Star V Hydrae ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Raghvendra Sahai Jet Propulsion Laboratory Y CoI: Dr. Mark R. Morris University of California - Los Angeles N CoI: Ms. Samantha Scibelli State University of New York at Stony N Brook CoI: Prof. Chinnathambi Muthumariappan Indian Institute of Astrophysics N ------------------------------------------------------------------------------------ Abstract The carbon star V Hya is experiencing heavy mass loss as it undergoes the transition from an AGB star to a planetary nebula (PN). This is possibly the earliest object known in this brief phase, which is so short that few nearby stars are likely to be caught in the act. Molecular observations reveal that a bipolar nebula has been established even at this early stage. Using STIS, we obtained high spatial-resolution long-slit optical spectra of V Hya spanning 3 epochs spaced apart by a year during each of two periods (2002-2004, 2011-2013). These data reveal high-velocity emission in [SII] lines from compact blobs located both on- and off-source, with the ejection axis executing a flip-flop, both in, and perpendicular to, the sky-plane. We have proposed a detailed model in which V Hya ejects high-speed (200-250 km/s) bullets once every 8.5 yr associated with periastron passage of a binary companion in an eccentric orbit with an 8.5 yr period. We suggest that the jet driver is an accretion disk (produced by gravitational capture of material from the primary) that is warped and precessing. Our model predicts the locations of previously ejected bullets in V Hya and future epochs at which new bullets will emerge. We now propose new STIS observations of these remarkable bullet ejections over two new epochs well separated from previous ones, to robustly test our model. The proposed observations will provide us with an unprecedented opportunity to look on as V Hya's circumstellar envelope is sculpted by these bullets. Our study will help solve the long-standing puzzle of how the spherical mass-loss envelopes of AGB stars evolve into bipolar and multipolar PNe. ------------------------------------------------------------------------------------ 15209( 2) - 05-Dec-2018 20:54:14 - [ 2] Observations Description ------------------------ We will utilise an observing set-up that uses a mosaic of 5 parallel slits aligned E-W to probe the spatio-kinematic structure of the emission-line blobs in the [SII]$\lambda\lambda\, 4069.7, 4077.5$ doublet. STIS will be used with G430M (tilt setting of 4194) and the $52{''}\times$0\farcs1 slit to obtain spectra in the $\lambda\lambda$4051-4337{\AA} range. From our previous data, the [SII]$\lambda$4066{\AA} line has a peak intensity that is about4$\times10^{-13}$ erg s$^{-1}$ cm$^{-2}$ {\AA}$^{-1}$ arcsec$^{-2}$ and a FWHM of about 1\AA. We will use exposure times ($\sim$1100\, s per dither position), and CR-SPLIT=2, which gives us a S/N$\gsim$40--80 at the peak of the [SII]$\lambda$4066{\AA} line, and a S/N$\gsim$15 in the continuum (which is roughly a factor 4 weaker in the offset slit, where the high-velocity bullet emission is strongest). This high S/N ratio is necessary because it allows us to measure the spatial offset of the peak from the source continuum with sub-pixel accuracy, which is important since the proper motion is about 0\farcs07 per year (and may decrease with time). In addition, we want to continue to be able to detect important fainter lines ([FeII]$\lambda$4241 \& 4285{\AA}) which we have detected previously, and which provide additional probes of the physical conditions in the bullet. The G430M observations will require 4 orbits per epochs. The available windows for observing V Hya given our STIS slit ORIENT constraints (we require an ORIENT within $\pm$4\arcdeg~of those used in the previous epochs) occur twice each calendar year, i.e., (1) in June/Aug, and (2) in Dec. ------------------------------------------------------------------------------------ 15209( 2) - 05-Dec-2018 20:54:14 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-HYDRAE STAR, CARBON STAR, RA=10H51M37.2566S +/- 0.1", J2000 V = 6.8 +/- 2 B=12.7 DISK, EMISSION LINE DEC=-21D15'0.32" +/- 0.1" NEBULA, PULSATING VARIABLE, WIND Reference Frame: ICRS Extended: YES Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -7.882627755744066E-4 0.00229 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 15209( 2) - 05-Dec-2018 20:54:14 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-PERP-TO-SLIT STIS-ALONG-SLIT Pattern_Purpose MOSAIC DITHER Number_Of_Points 5 3 Point_Spacing 0.1 0.22851 Line_Spacing Coordinate_Frame POS-TARG POS-TARG Pattern_Orient 0.0 90.0 Angle_Between_Sides Center_Pattern YES NO Pattern_Comments: pattern should produce a mosaic of 5 slits, spaced apart by 0.1 arcsec, with a 3-point dither along the slit for each slit position ------------------------------------------------------------------------------------------------------------------------------------ 15209( 2) - 05-Dec-2018 20:54:14 - [ 5] Visit: 01 Visit Requirements: PCS MODE FINE; SCHED 30%; ORIENT 128.5D TO 136.5 D; ORIENT 308.5D TO 316.5 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 V-HYDRAE STIS/CCD ACQ F25ND3 MIRROR 1 1.3 S (1.3 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 V-HYDRAE STIS/CCD ACQ/PEA 52X0.1 G750L 7751 1 1.0 S (1 K S) ------------------------------------------------------------------------------------------------------------------------------------ 3 V-HYDRAE STIS/CCD ACCUM 52X0.1 G430M 4194 1 560 S PATTERN 1 3 see below (9160 S) Comments: 15 exposures to produce a mosaic of 5 slits, spaced apart by 0.1 arcsec, with a 3-point dither along the slit for each slit position ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-HYDRAE 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A V-HYDRAE 2 STIS/CCD ACQ/PEA 52X0.1 G750L 7751 none none none none 1 N/A K V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 1 none 1 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 1 none 2 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 2 none 1 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 2 none 2 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 3 none 1 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 1 3 none 2 1 284.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 1 none 1 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 1 none 2 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 2 none 1 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 2 none 2 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 3 none 1 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 2 3 none 2 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 1 none 1 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 1 none 2 2 313.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 2 none 1 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 2 none 2 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 3 none 1 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 3 3 none 2 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 1 none 1 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 1 none 2 3 310.0 S 15209( 2) - 05-Dec-2018 20:54:14 - [ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 2 none 1 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 2 none 2 3 310.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 3 none 1 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 4 3 none 2 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 1 none 1 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 1 none 2 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 2 none 1 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 2 none 2 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 3 none 1 4 309.0 S V-HYDRAE 3 STIS/CCD ACCUM 52X0.1 G430M 4194 5 3 none 2 4 309.0 S 15209( 2) - 05-Dec-2018 20:54:14 - [ 7] Summary Form for Proposal 15209 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.1, F25ND3 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 128.5D TO 136.5 D, ORIENT 308.5D TO 316.5 D, PATTERN 1 3, PCS MODE FINE, SCHED 30% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G430M, G750L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-HYDRAE ------------------------------------------------------------------------------------------------------------------------------------