High spatial resolution optical imaging of the multiple T Tauri system LkHα 262/LkHα 263

Abstract

We report high spatial resolution i' band imaging of the multiple T Tauri system LkHα 262/LkHα 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2 m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkHα 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkHα 263 are co-moving, that there is orbital motion in the AB pair, and, remarkably, that LkHα 262-263 is a common proper motion system with less than 1 mas/yr relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low-mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.

High-Resolution Imaging in the Visible with Faint Reference Stars on Large Ground-Based Telescopes

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“…Following the work of van Dam & Lane (2002) we have based our wavefront recovery algorithms on the use of Radon transforms. These have seldom been used in astronomical applications (though see Starck et al, 2003) but are very well studied and widely used in, for example, x-ray computerised tomography systems where they are particularly successful.…”

“…The theoretical point spread function predicted from Kolmogorov turbulence models (Fried, 1978) is known as a Moffat profile (Racine, 1996, andTrujillo et al, 2001 andreferences therein). This profile has a core that is essentially Gaussian but with significantly broader wings.…”

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SOWAT: Speckle Observations with Alleviated Turbulence

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