Ostreococcus tauri is a unicellular green alga and amongst the smallest and simplest free-living eukaryotes. The O. tauri genome sequence was determined in 2006. Molecular, physiological and taxonomic data that has been generated since then highlight its potential as a simple model species for algae and plants. However, its proteome remains largely unexplored. This paper describes the global pr...

A deep 13.5 ksec ROSAT PSPC pointed observation in the Chamaeleon II (Cha II) cloud is reported. 40 X-ray sources are detected of which 14 can be identified with previously known young stellar objects (YSOs), namely IRAS sources, classical T Tauri stars and weak T Tauri stars. From spectroscopic followup observations, four new weak T Tauri candidates have been found. The X-ray sources are mainl...

Based on high-resolution UVES spectra we found that the radial velocity (RV) dispersion of nine of twelve known young bona fide and candidate brown dwarfs in the Cha I dark cloud is 2.0 kms, i.e. significantly smaller than the RV dispersion of T Tauri stars in Cha I (3.6 km/s) and only slightly larger than the dispersion of the surrounding molecular gas (1.2 km/s) (Mizuno et al. 1999). This res...

Results are presented from a monitoring program looking for variations of the equivalent width and flux of Hα, and of the continuum flux, in 18 classical and 18 weak line T Tauri stars, and one Herbig Ae/Be star, on time scales down to 5 minutes. The stars were observed simultaiously for 14 hours using the multiobject-spectrograph FLAIR on the UK Schmidt Telescope. The campaign turned up two ev...

We describe near-IR imaging data for a sample of 23 Class I sources in the Taurus-Auriga dark clouds. Combining our data with previous photometry, we detect brightness variations of 0.1–0.5 mag in many sources. The near-IR morphologies are consistent with millimeter continuum measurements. Most ( 60%) of the sample are true protostars; the rest may be objects in transition between Class I and C...

We examine the implications of a beat frequency modulated model of T Tauri accretion. In particular we show that measurements of the variability of accretion generated lines can be used in conjunction with existing photometry to obtain a measurement of the underlying photospheric and disc ux. This provides an independent way of checking spectral energy distribution modelling. In addition, we sh...