CONICA: the high-resolution near-infrared camera for the ESO VLT

Lenzen, R.; Hofmann, R.; Bizenberger, Peter; Tusche, Andreas

doi:10.1117/12.317287

Cited by 116 publications

(68 citation statements)

References 2 publications

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“…TWA22 AB was observed at the 8.2 m VLT UT4 Yepun with the Nasmyth Adaptive Optics (AO) System NAOS (Rousset et al 2000) coupled to the high-resolution near-IR camera CONICA (Lenzen et al 1998). NAOS and CONICA (NACO) resolved the system as a tight binary for the first time on were also used coupled to a neutral density (attenuation factor of 80).…”

Section: Vlt/naco Observationsmentioning

confidence: 99%

The young, tight, and low-mass binary TWA22AB: a new calibrator for evolutionary models?

Bonnefoy¹,

Chauvin²,

Dumas³

et al. 2009

A&A

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Context. Tight binaries discovered in young, nearby associations are ideal targets for providing dynamical mass measurements to test the physics of evolutionary models at young ages and very low masses. Aims. We report the binarity of TWA22 for the first time. We aim at monitoring the orbit of this young and tight system to determine its total dynamical mass using an accurate distance determination. We also intend to characterize the physical properties (luminosity, effective temperature, and surface gravity) of each component based on near-infrared photometric and spectroscopic observations. Methods. We used the adaptive-optics assisted imager NACO to resolve the components, to monitor the complete orbit and to obtain the relative near-infrared photometry of TWA22 AB. The adaptive-optics assisted integral field spectrometer SINFONI was also used to obtain medium-resolution (R λ = 1500−2000) spectra in JHK bands. Comparison with empirical and synthetic librairies were necessary for deriving the spectral type, the effective temperature, and the surface gravity for each component of the system. Results. Based on an accurate trigonometric distance (17.5±0.2 pc) determination, we infer a total dynamical mass of 220±21 M Jup for the system. From the complete set of spectra, we find an effective temperature T eff = 2900 +200 −200 K for TWA22 A and T eff = 2900 +200 −100 K for TWA22 B and surface gravities between 4.0 and 5.5 dex. From our photometry and an M6 ± 1 spectral type for both components, we find luminosities of log(L/L ) = −2.11 ± 0.13 dex and log(L/L ) = −2.30 ± 0.16 dex for TWA22 A and B, respectively. By comparing these parameters with evolutionary models, we question the age and the multiplicity of this system. We also discuss a possible underestimation of the mass predicted by evolutionary models for young stars close to the substellar boundary.

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Section: Vlt/naco Observationsmentioning

confidence: 99%

The young, tight, and low-mass binary TWA22AB: a new calibrator for evolutionary models?

Bonnefoy¹,

Chauvin²,

Dumas³

et al. 2009

A&A

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“…The observations were carried out in April 2002 during the commissioning of the NACO/VLT system (Lenzen et al 1998;Rousset et al 2003;Hartung et al 2000) in the Ks band. In order to simultaneously measure two orthogonal components of the polarized light, a Wollaston prism was introduced in the light path.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

NACO polarimetric differential imaging of TW Hya

Apai

Pascucci

Brandner

et al. 2004

A&A

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Abstract. We present high-contrast imaging data on the disk of the classical T Tauri star TW Hya. The images were obtained through the polarimetric differential imaging technique with the adaptive optics system NACO. Our commissioning data show the presence of polarized disk emission between 0.1 and 1.4 from the star. We derive the first Ks-band radial polarized intensity distribution. We show that the polarized intensity compares well to shorter wavelengths surface brightness observations and confirm the previously reported gradual slope change around 0.8 . These results show the potential of the new polarimetric differential imaging technique at 8 m-class telescopes to map the inner regions of protoplanetary disks.

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“…The images were taken with the new NAOS/CONICA adaptive optics-assisted imager/spectrometer (Lenzen et al 1998;Rousset et al 1998;Brandner et al 2002) at the Unit Telescope 4 (UT4; Yepun) at the European Southern Observatory (ESO) Very Large Telescope (VLT). 1 The 3 m spectroscopy was carried out with ISAAC on VLT UT1 (Antu).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Young Stars at the Center of the Milky Way?

Eckart

Moultaka

Viehmann

et al. 2004

ApJ

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We present results from the first diffraction-limited images of the Galactic center (GC) at 1.6, 2.1, and 3.8 m with the new adaptive optics (AO) camera NAOS/CONICA at the ESO Very Large Telescope, as well as 3-4 m low-resolution spectroscopy. We have discovered a small (0.13 lt-yr diameter) cluster of compact sources about 0B5 north of IRS 13 with strong IR excesses due to T > 500 K dust. The nature of the sources is unclear. They may be a cluster of highly extincted stars that heat the local environment of the minispiral. We also consider an explanation that involves the presence of young stars at evolutionary stages between young stellar objects and Herbig Ae/Be objects with ages of about 0.1 to 1 million yr. This scenario would imply more recent star formation in the GC than previously suspected. The AO observations also resolve the central IRS 13 complex. In addition to the previously known bright stars E1 and E2, the K-and L 0 -band images for the first time resolve object E3 into two components, E3N and E3c. The latter one is closest to the 7 mm Very Large Array radio continuum source found at the location of the IRS 13 complex. E3c may be associated with a strong stellar wind or a dusty Wolf-Rayet-like star at that location.

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CONICA: the high-resolution near-infrared camera for the ESO VLT

Cited by 116 publications

References 2 publications

The young, tight, and low-mass binary TWA22AB: a new calibrator for evolutionary models?

The young, tight, and low-mass binary TWA22AB: a new calibrator for evolutionary models?

NACO polarimetric differential imaging of TW Hya

Young Stars at the Center of the Milky Way?

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