Spatially Resolved Imaging Spectroscopy of T Tauri

Kasper, Markus; Feldt, M.; Herbst, Thomas; Hippler, S.; Ott, T.; Tacconi-Garman, L. E.

doi:10.1086/338803

Cited by 24 publications

(32 citation statements)

References 33 publications

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“…We did not find any conclusive evidence for any spatial extension of the Brγ line. This is consistent with Kasper et al (2002), who found that extended Brγ emission, if any, is confined to within 6 AU of the star. This argues against the existence of an extended PDR.…”

Section: Other Indicatorssupporting

confidence: 93%

Spatially resolved H₂emission from the disk around T Tau N

Gustafsson

Labadie

Herbst

et al. 2008

A&A

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Context. Molecular hydrogen is the main constituent of circumstellar disks and could be an important tracer for the evolution and structure of such disks. So far, H 2 has only been detected in a few disks and only through spectroscopic observations, resulting in a limited knowledge of the spatial distribution of the H 2 emitting gas. Aims. We report the detection of quiescent H 2 emission in a spatially resolved ring-like structure within 100 AU of T Tau N. We present evidence to show that the emission most likely arises from shocks in the atmosphere of a nearly face-on disk around T Tau N. Methods. Using high spatial resolution 3D spectroscopic K-band data, we trace the spatial distribution of several H 2 NIR rovibrational lines in the vicinity of T Tau N. We examine the structure of the circumstellar material around the star through SED modeling. Then, we use models of shocks and UV+X-ray irradiation to reproduce the H 2 line flux and line ratios in order to test how the H 2 is excited. Results. We detect weak H 2 emission from the v = 1−0 S(0), S(1), Q(1) lines and the v = 2−1 S(1) line in a ring-like structure around T Tau N between 0. 1 (∼15 AU) and 0. 7 (∼100 AU) from the star. The v = 1−0 S(0) and v = 2−1 S(1) lines are detected only in the outer parts of the ring structure. Closer to the star, the strong continuum limits our sensitivity to these lines. The total flux of the v = 1−0 S(1) line is 1.8 × 10 −14 erg s −1 cm −2 , similar to previous measurements of H 2 in circumstellar disks. The velocity of the H 2 emitting gas around T Tau N is consistent with the rest velocity of the star, and the H 2 does not seem to be part of a collimated outflow. Both shocks impinging on the surface of a disk and irradiation of a disk by UV-photons and X-rays from the central star are plausible candidates for the H 2 excitation mechanism. However, irradiation should not create a large degree of excitation at radii larger than 20 AU. Most likely the H 2 emission arises in the atmosphere of a flared disk with radius 85−100 AU and mass 0.005−0.5 M , where the gas is excited by shocks created when a wide-angle wind impinges on the disk. The H 2 emission could also originate from shock excitation in the cavity walls of an envelope, but this requires an unusually high velocity of the wide-angle wind from T Tau N.

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Section: Other Indicatorssupporting

confidence: 93%

Spatially resolved H₂emission from the disk around T Tau N

Gustafsson

Labadie

Herbst

et al. 2008

A&A

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“…Previous studies found H 2 emission around T Tau N and S (Kasper et al 2002;Beck et al 2004;Gustafsson et al 2010), which our observations also confirm. Our CntK2, Br-γ, and H 2 images (Fig.…”

Section: Classical Imagingsupporting

confidence: 91%

Examining the T Tauri system with SPHERE

Csépány

Ancker

Ábrahám

et al. 2015

A&A

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Context. The prototypical low-mass young stellar object, T Tauri, is a well-studied multiple system with at least three components. Aims. We aim to explore the T Tau system with the highest spatial resolution, study the time evolution of the known components, and re-determine the orbital parameters of the stars. Methods. Near-infrared classical imaging and integral field spectrograph observations were obtained during the Science Verification of SPHERE, the new high-contrast imaging facility at the VLT. The obtained FWHM of the primary star varies between 0.050 and 0.059 , making these the highest spatial resolution near-infrared images of the T Tauri system obtained to date. Results. Our near-infrared images confirm the presence of extended emission south of T Tau Sa, reported in the literature. New narrow-band images show, for the first time, that this feature shows strong emission in both the Br-γ and H 2 1−0 S(1) lines. Broadband imaging at 2.27 µm shows that T Tau Sa is 0.92 mag brighter than T Tau Sb, which is in contrast to observations from Jan. 2014 (when T Tau Sa was fainter than Sb), and demonstrates that T Tau Sa has entered a new period of high variability. The newly obtained astrometric positions of T Tau Sa and Sb agree with orbital fits from previous works. The orbit of T Tau S (the centre of gravity of Sa and Sb) around T Tau N is poorly constrained by the available observations and can be fit with a range of orbits ranging from a nearly circular orbit with a period of 475 years to highly eccentric orbits with periods up to 2.7 × 10 4 years. We also detected a feature south of T Tau N, at a distance of 144 ± 3 mas, which shows the properties of a new companion.

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“…Some of the H 2 emission is most likely generated by shock heating (Herbst et al 1997), but Saucedo et al (2003) have also found fluorescent H 2 pumped by Lyα, suggesting the action of lowdensity, wide opening-angle outflows driving cavities into the molecular medium. No significant H 2 emission is associated with the stars themselves (Kasper et al 2002;Duchêne et al 2005;Herbst et al 2007). …”

Section: Introductionmentioning

confidence: 99%

“…All three components are actively accreting and are as yet spatially unresolved, i.e., point-like, hydrogen recombination line emitters (e.g., Kasper et al 2002;Duchêne et al 2005). The near-infrared brightness of T Tauri Sa is quite variable owing to changes in the accretion rate on timescales of days.…”

Section: Introductionmentioning

confidence: 99%

“…It is widely believed that T Tauri Sa is extincted by an almost edge-on, small (3−5 AU radius), circumstellar disk hiding the stellar photosphere (e.g., Koresko 2000;Kasper et al 2002;Beck et al 2004). There is also an apparent lack of cold dust emission from T Tauri S, implying a rather small mass of its circumstellar material (Hogerheijde et al 1997).…”

Section: Introductionmentioning

confidence: 99%

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New circumstellar structure in the T Tauri system

Kasper

Santhakumari

Herbst

et al. 2016

A&A

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Aims. The immediate vicinity of T Tauri was observed with the new high-contrast imaging instrument SPHERE at the VLT to resolve remaining mysteries of the system, such as the putative small edge-on disk around T Tauri Sa and the assignment of the complex outflow patterns to the individual stars. Methods. We used SPHERE IRDIS narrow-band classical imaging in Paβ, Brγ, and the ν = 1−0 S(1) line of H 2 , as well as in the nearby continua to obtain high spatial resolution and high-contrast images over the near-infrared spectral range. Line maps were created by subtracting the nearby continuum. We also reanalyzed coronagraphic data taken with SPHERE's integral field spectrograph in J-and H-band with the goal of obtaining a precise extinction estimate to T Tauri Sb, and of verifying the recently reported claim of another stellar or substellar object in the system. Results. A previously unknown coiling structure is observed southwest of the stars in reflected light, which points to the vicinity of T Tauri N. We map the circumbinary emission from T Tauri S in J-and H-band scattered light for the first time, showing a morphology that differs significantly from that observed in K-band. Molecular Hydrogen emission is found southwest of the stars, near the coiling structure. We also detect the H 2 emitting region T Tauri NW. The motion of T Tauri NW with respect to T Tauri N and S between previous images and our 2014 data provides strong evidence that the southeast-northwest outflow triggering T Tauri NW is likely to be associated with T Tauri S. We also present accurate relative photometry of the stars, which confirms that T Tauri Sa is brightening again. Our analysis rules out the presence of the recently proposed companion to T Tauri N with high confidence.

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Spatially Resolved Imaging Spectroscopy of T Tauri

Cited by 24 publications

References 33 publications

Spatially resolved H₂emission from the disk around T Tau N

Spatially resolved H₂emission from the disk around T Tau N

Examining the T Tauri system with SPHERE

New circumstellar structure in the T Tauri system

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Spatially Resolved Imaging Spectroscopy of T Tauri

Cited by 24 publications

References 33 publications

Spatially resolved H2emission from the disk around T Tau N

Spatially resolved H2emission from the disk around T Tau N

Examining the T Tauri system with SPHERE

New circumstellar structure in the T Tauri system

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Product

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Spatially resolved H₂emission from the disk around T Tau N

Spatially resolved H₂emission from the disk around T Tau N