High-Resolution Near-Infrared Images of the T Tauri Binary System XZ Tauri

Aims. In this paper, we aim to characterise the surface magnetic fields of a sample of eight T Tauri stars from high-resolution near-infrared spectroscopy. Some stars in our sample are known to be magnetic from previous spectroscopic or spectropolarimetric studies. Our goals are firstly to apply Zeeman broadening modelling to T Tauri stars with high-resolution data, secondly to expand the sample of stars with measured surface magnetic field strengths, thirdly to investigate possible rotational or long-term magnetic variability by comparing spectral time series of given targets, and fourthly to compare the magnetic field modulus ⟨B⟩ tracing small-scale magnetic fields to those of large-scale magnetic fields derived by Stokes V Zeeman Doppler Imaging (ZDI) studies. Methods. We modelled the Zeeman broadening of magnetically sensitive spectral lines in the near-infrared K-band from high-resolution spectra by using magnetic spectrum synthesis based on realistic model atmospheres and by using different descriptions of the surface magnetic field. We developped a Bayesian framework that selects the complexity of the magnetic field prescription based on the information contained in the data. Results. We obtain individual magnetic field measurements for each star in our sample using four different models. We find that the Bayesian Model 4 performs best in the range of magnetic fields measured on the sample (from 1.5 kG to 4.4 kG). We do not detect a strong rotational variation of ⟨B⟩ with a mean peak-to-peak variation of 0.3 kG. Our confidence intervals are of the same order of magnitude, which suggests that the Zeeman broadening is produced by a small-scale magnetic field homogeneously distributed over stellar surfaces. A comparison of our results with mean large-scale magnetic field measurements from Stokes V ZDI show different fractions of mean field strength being recovered, from 25–42% for relatively simple poloidal axisymmetric field topologies to 2–11% for more complex fields.

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Searching for H2 emission from protoplanetary disks using near- and mid-infrared high-resolution spectroscopy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308016827 ◽

2007 ◽

Vol 3 (S249) ◽

pp. 359-368

Author(s):

A. Carmona ◽

M. E. van den Ancker ◽

Th. Henning ◽

Ya. Pavlyuchenkov ◽

C. P. Dullemond ◽

...

Keyword(s):

Surface Layer ◽

High Resolution ◽

Near Infrared ◽

Protoplanetary Disks ◽

High Resolution Spectroscopy ◽

Disk Model ◽

Mid Infrared ◽

T Tauri ◽

Hα Emission ◽

Ir Emission

AbstractThe mass and dynamics of protoplanetary disks are dominated by molecular hydrogen (H2). However, observationally very little is known about the H2. In this paper, we discuss two projects aimed to constrain the properties of H2 in the disk's planet forming region (R<50AU). First, we present a sensitive survey for pure-rotational H2 emission at 12.278 and 17.035 μm in a sample of nearby Herbig Ae/Be and T Tauri stars using VISIR, ESO's VLT high-resolution mid-infrared spectrograph. Second, we report on a search for H2 ro-vibrational emission at 2.1228, 2.2233 and 2.2477 μm in the classical T Tauri star LkHα 264 and the debris disk 49 Cet employing CRIRES, ESO's VLT high-resolution near-infrared spectrograph.VISIR project: none of the sources show H2 mid-IR emission. The observed disks contain less than a few tenths of MJupiter of optically thin H2 at 150 K, and less than a few MEarth at T>300 K. % and higher T. Our non-detections are consistent with the low flux levels expected from the small amount of H2 gas in the surface layer of a Chiang and Goldreich (1997) Herbig Ae two-layer disk model. In our sources the H2 and dust in the surface layer have not significantly departed from thermal coupling (Tgas/Tdust<2) and the gas-to-dust ratio in the surface layer is very likely <1000.CRIRES project: The H2 lines at 2.1218 μm and 2.2233 μm are detected in LkHα 264. An upper limit on the 2.2477 μm H2 line flux in LkHα 264 is derived. 49 Cet does not exhibit H2 emission in any of observed lines. There are a few MMoon of optically thin hot H2 in the inner disk (∼0.1 AU) of LkHα 264, and less than a tenth of a MMoon of hot H2 in the inner disk of 49 Cet. The shape of the 1–0 S(0) line indicates that LkHα disk is close to face-on (i<35o). The measured 1–0 S(0)/1–0 S(1) and 2–1 S(1)/1–0 S(1) line ratios in LkHα 264 indicate that the H2 is thermally excited at T<1500 K. The lack of H2 emission in the NIR spectra of 49 Cet and the absence of Hα emission suggest that the gas in the inner disk of 49 Cet has dissipated.

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High-Resolution Optical and Near-Infrared Images of the FS Tauri Circumbinary Disk

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/63.3.543 ◽

2011 ◽

Vol 63 (3) ◽

pp. 543-554 ◽

Cited By ~ 14

Author(s):

Tomonori Hioki ◽

Yoichi Itoh ◽

Yumiko Oasa ◽

Misato Fukagawa ◽

Masahiko Hayashi

Keyword(s):

High Resolution ◽

Near Infrared ◽

Infrared Images

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Resolved Near‐Infrared Spectroscopy of the Mysterious Pre–Main‐Sequence Binary System T Tauri S

The Astrophysical Journal ◽

10.1086/338987 ◽

2002 ◽

Vol 568 (2) ◽

pp. 771-778 ◽

Cited By ~ 52

Author(s):

G. Duchene ◽

A. M. Ghez ◽

C. McCabe

Keyword(s):

Infrared Spectroscopy ◽

Binary System ◽

Near Infrared Spectroscopy ◽

Main Sequence ◽

Near Infrared ◽

T Tauri

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Near-Infrared Coronagraphic Observations of the T Tauri Binary System UY Aur

The Astronomical Journal ◽

10.1086/519737 ◽

2007 ◽

Vol 134 (2) ◽

pp. 880-885 ◽

Cited By ~ 26

Author(s):

Tomonori Hioki ◽

Yoichi Itoh ◽

Yumiko Oasa ◽

Misato Fukagawa ◽

Tomoyuki Kudo ◽

...

Keyword(s):

Binary System ◽

Near Infrared ◽

T Tauri

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High‐Resolution Near‐Infrared Images and Models of the Circumstellar Disk in HH 30

The Astrophysical Journal ◽

10.1086/321627 ◽

2001 ◽

Vol 556 (2) ◽

pp. 958-969 ◽

Cited By ~ 80

Author(s):

Angela S. Cotera ◽

Barbara A. Whitney ◽

Erick Young ◽

Michael J. Wolff ◽

Kenneth Wood ◽

...

Keyword(s):

High Resolution ◽

Near Infrared ◽

Circumstellar Disk ◽

Infrared Images

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The wind and the magnetospheric accretion onto the T Tauri star S Coronae Australis at sub-au resolution

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731058 ◽

2017 ◽

Vol 608 ◽

pp. A78 ◽

Cited By ~ 1

Author(s):

◽

R. Garcia Lopez ◽

K. Perraut ◽

A. Caratti o Garatti ◽

B. Lazareff ◽

...

Keyword(s):

Binary System ◽

Spectral Resolution ◽

Near Infrared ◽

Line Emission ◽

High Spectral Resolution ◽

Simultaneous Presence ◽

Field Mode ◽

T Tauri ◽

Magnetospheric Accretion ◽

The Continuum

Aims. To investigate the inner regions of protoplanetary discs, we performed near-infrared interferometric observations of the classical T Tauri binary system S CrA. Methods. We present the first VLTI-GRAVITY high spectral resolution (R ~ 4000) observations of a classical T Tauri binary, S CrA (composed of S CrA N and S CrA S and separated by ~1.̋4), combining the four 8m telescopes in dual-field mode. Results. Our observations in the near-infrared K-band continuum reveal a disc around each binary component, with similar half-flux radii of about 0.1 au at d ~ 130 pc, inclinations (i = 28 ± 3° and i = 22 ± 6°), and position angles (PA = 0°± 6° and PA = –2°± 12°), suggesting that they formed from the fragmentation of a common disc. The S CrA N spectrum shows bright He i and Brγ line emission exhibiting inverse P Cygni profiles, typically associated with infalling gas. The continuum-compensated Brγ line visibilities of S CrA N show the presence of a compact Brγ emitting region whose radius is about ~0.06 au, which is twice as big as the truncation radius. This component is mostly tracing a wind. Moreover, a slight radius change between the blue- and red-shifted Brγ line components is marginally detected. Conclusions. The presence of an inverse P Cygni profile in the He i and Brγ lines, along with the tentative detection of a slightly larger size of the blue-shifted Brγ line component, hint at the simultaneous presence of a wind and magnetospheric accretion in S CrA N.

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Integrated Approach for Sclera Recognition and Eye Gaze Detection

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i7.188 ◽

2018 ◽

Vol 6 (7) ◽

pp. 77

Author(s):

Snehal S. Rajole ◽

J. V. Shinde

Keyword(s):

Near Infrared ◽

Eye Gaze ◽

Integrated Approach ◽

Error Rates ◽

Infrared Images ◽

Scaling Method ◽

Extensive Simulation ◽

Sclera Recognition ◽

Gaze Detection ◽

Biometric Trait

In this paper we proposed unique technique which is adaptive to noisy images for eye gaze detection as processing noisy sclera images captured at-a-distance and on-the-move has not been extensively investigated. Sclera blood vessels have been investigated recently as an efficient biometric trait. Capturing part of the eye with a normal camera using visible-wavelength images rather than near infrared images has provoked research interest. This technique involves sclera template rotation alignment and a distance scaling method to minimize the error rates when noisy eye images are captured at-a-distance and on-the move. The proposed system is tested and results are generated by extensive simulation in java.

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