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Tomonori 1 Hioki ([email protected]), Yoichi 1 Itoh , Yumiko 1 Oasa , Misato 2 Fukagawa , SDPS 3 Team (1: Kobe University, 2: Nagoya University, 3: NAOJ) ☆Abstract☆ We obtained a high spatial resolution (FWHM ~ 0.1”) near-infrared image of XZ Tau, a 0.3” separated binary system, using Subaru/CIAO. A jetlike structure (Jet1 of Fig 5) was detected at northeast side of the binary. It is possibly driven from the secondary. Previous HST observations of the binary showed a shock (bubble structure of Fig 3) created by another jet (Jet2 of Fig 5) from the primary. 1. Introduction 4. Result 1.1 Motivation 4.1 Jet from the secondary ・Many T Tauri stars (~1 Myr) have protoplanetary disks and bipolar jets. Jet ・The observations have focused mainly on single T Tauri stars. Fig5 presents that the jet (Jet1) drive from the secondary in the direction of P.A.~54 deg. Disk Brightness ∝ r -4 ・ More than half of T Tauri stars are binaries. (Ghez et al) Fig1 Circumstellar A limited number of studies have so far examined the disks disk and jet of HH30 and the jets around binary systems. (HST/WFPC2; (e.g., UY Aur; Hioki et al. 2007) Burrows et al. 1996) 1.2 CIAO-Coronagraphic Imager with Adaptive Optics Limiting magnitude ●:Northeast ○:Southwest Fig6 Brightness of the northeast (●) and southwest (○) jets from the secondary ・Mask has ~2% transmission for the central star. Fig5 Coronagraphic image of XZ Tau <Northeast side> ・A pupil Lyot stop reduce the diffracted light. ①Extending to ~ 300 AU from the secondary ②Surface brightness ∝ r ^-4 (r : distance from the secondary) If the structure is scattering from the central binary, its brightness ∝ r^-3. ⇒CIAO is effective for the detection of protoplanetary disks and jets around the stellar vicinity. Fig2 Coronagraph structure 1.3 XZ Tau (Classical T Tauri Binary) ・Location: Taurus star forming region (L1551; d~140 pc, Elias 1978) ・Separation: ~0”.3 (=40 AU; Haas et al. 1990) ・Mass: 0.4 Msun (Primary), 0.3 Msun (Secondary) (Hartigan & Kenyon 2003) 1.4 Previous Study of XZ Tau ①Detection of a bipolar jet (Mundt et al. 1988, 1990) ⇒Blue-shifted (northeast side) & red-shifted (southwest side) Therefore, [1] the more it is distant from the stars, the optically thinner or [2] it emits not only by scattering but also by emission lines (such as [Fe II]). <Southwest side> Outstanding structure is not seen. ⇒The jet is probably obscured by a circumbinary disk (if any) in the plane perpendicular to the jet. 4.2 H-band Magnitude, Separation, Position Angle ②HST/WFPC2 Observations (Fig 3; Krist et al. 1997, 1999, Coffey et al. 2004) ⇒A bubble of emission nebulosity was detected to north (P.A. ~20 deg) of the binary system. Its structure is the following: ・The bubble extending with time ・[S II], Hα, and [O I] emission lines ・The bubble = Shock created by collision between circumstellar material and jet from the primary?? ・Accretion from the circumstellar disk around the primary is very active(White & Ghez 2001). ・The primary is an EXor, which periodically undergo outbursts (Coffey et al. 2004). Fig3 XZ Tau image taken by HST/WFPC2 (R-band; Krist et al. 1999) Blue: Secondary (~0.6 mag up) Red: Primary (~1.3 mag down) Blue:Separation ~0.3” (=42 AU) Red: Angular velocity ~1.2 deg/yr These variations may originate from: ⇒Orbital period ~300 yrs Total mass ~0.8 M sun ・variable accretion rate to the stars ・ rotation of the secondary with hot spots on its surface. (assuming its orbit is circular) The variation of the primary possibly contributes to its outburst. On the other hand, it is thought that the secondary is equable compared with the primary. 5. Discussion ⇒Does the secondary drive the jet? or not?? 5.1 Jet? or Reflection Nebulae? 2.Observations Date: 2005 Nov 9, 2007 Dec 16 Mask size [arcsec] Ex time [sec] FWHM [arcsec] Instrument: Subaru/ CIAO XZ Tau 0.6 720 0.1 FOV: 22” by 22” PSF-ref 0.6 228 0.1 It is possibility that the jet-like structure is scattering from the central binary. ⇒We also carried out the [Fe II] observations in 2007 Dec. 5.2 Result of [Fe II] image Wavelength: H-band (1.6 um), [Fe II] N PSF-reference stars were obtained before and after XZ Tau observations. 3.Reduction (IRAF) E 北 東 ①Dark subtraction ②Flat-fielding by twilight flat ③Hot and bad pixel removal ④Sky subtraction Primary ● Was a weak [Fe II] emission detected?? If it is real, the jet-like structure corresponds to the jet from the secondary. Because forbidden lines are indicative of the jet from young stellar objects. ● 1”=140 AU 1” = 140 AU ⑤Shift each frame to adjust the position of the stars Fig4 Raw image of XZ Tau ⑥Rotation of PSF-reference stars to adjust the position angle of the spider ⑦Combining XZ Tau frames subtracted their PSFs Secondary But… This image is the result of simplified reduction. More detailed reduction is needed!! Fig7 [Fe II] coronagraphic image of the XZ Tau binary (ex time: 1280 s)