Exoplanets and Stellar Physics

Abstract:

Magnetoencephalography (MEG) is a non-invasive technique of functional imaging which measures weak magnetic fields in the brain due to the currents generated from neural synapses. MEG systems contain a couple of hundred channels, making it difficult to visualize the raw measurements directly. As an alternative to rendering epileptic data, we demonstrate how MEG measurements can be mapped to a cortical surface by using a software package called FreeSurfer. We fuse MEG data with Magnetic Resonance Image (MRI) by plotting the MEG amplitude on top of the MRI images of gray matter surface. In addition to the surface, we render the MEG intensity in the convoluted regions, e.g. sulci, by computationally "inflating" the brain. These techniques are utilized for experimental study currently, and can be extended for diagnostic purposes in the future. © 2006 IEEE.

Abstract:

We review the observations of extrasolar planets, ongoing developments in theories of planet formation, orbital migration and the evolution of multiplanet systems. © 2006 IOP Publishing Ltd.

Abstract:

We report on the results of a V- and i-band time-series photometric survey of M34 (NGC 1039) using the Wide Field Camera (WFC) on the Isaac Newton Telescope (INT), achieving better than 1 per cent precision per data point for 13 lsim; i ≲ 17. Candidate cluster members were selected from a V versus V - I colour-magnitude diagram over 14 < V < 24 (0.12 ≲ M/M⊙ 1.0), finding 714 candidates, of which we expect ∼400 to be real cluster members (taking into account contamination from the field). The mass function was computed, and found to be consistent with a lognormal distribution in dN/d log M. Searching for periodic variable objects in the candidate members gave 105 detections over the mass range 0.25 < M/M⊙ < 1.0. The distribution of rotation periods for 0.4 < M/M⊙ < 1.0 was found to peak at ∼7 d, with a tail of fast rotators down to periods of ∼0.8 d. For 0.25 < M/M⊙ < 0.4 we found a peak at short periods, with a lack of slow rotators (e.g. P ≳ 5 d), consistent with the work of other authors at very low masses. Our results are interpreted in the context of previous work, finding that we reproduce the same general features in the rotational period distributions. A number of rapid rotators were found with velocities ∼ a factor of 2 lower than in the Pleiades, consistent with models of angular momentum evolution assuming solid body rotation without needing to invoke core-envelope decoupling. © 2006 RAS.

Abstract:

SWIFT is an adaptive optics assisted integral field spectrograph covering the I and z astronomical bands (0.7-1.0 mu m) at a spectral resolving power R <= 5000. At its heart is an all-glass image slicer with high throughput based on a novel de-magnifying design allowing a compact instrument. SWIFT profits from two recent developments: (i) the improved ability of second generation adaptive optics systems to correct for atmospheric turbulence in SWIFTS's bandpass, and (ii) the availability of CCD array detectors with high quantum efficiency at very red wavelengths. It is a dedicated integral field spectrograph, specifically built to address a range of interesting astrophysical questions. (c) 2005 Elsevier B.V. All rights reserved.