The Ryle Telescope was used for some years for monitoring variable sources (in addition to its role in source-surveys related to the Sunyaev-Zeldovitch studies). The instrument is now transformed into the "AMI large array": see the AMI pages for details. ... The rebuild took place between 2006 June and mid-2008; between these dates there is no useful data available. ... For some sources there are many plots, organised by date: . ...

. XMM Radiation Environment Models and Monitor . Introduction . Representative Orbits . XMM RM – Geographic Coordinates . Magnetospheric Coordinates (B L) . XMM Data in [B,L] Coordinates . XMM RM – [R, ?] Coordinates . XMM RM Data in L-localtime – No External B Model . XMM RM in L-LocalTime . Solar Proton Contribution . Effects to be Considered . Conclusions . Problems Encountered . Other Points/ Future Activities . Author: Hugh Evans . Email: hevans@estec.esa.nl@estec.esa.nl

Next: Rotation Periods of ZAMS stars Previous: T Tauri Stars . ... The first attempts to directly measure periodic modulation of T Tauri stars occurred in the early 1980s. Rydgren & Vrba (1983) observed four PMS stars using photoelectric photometry over a period of seven consecutive photometric nights. ... Because the spot lifetime is much longer than the rotational period, the observed effect will be a modulation of the light from the star synchronously with the rotation period. ...

... More on 51 Peg: . The discovery of a Jupiter--mass planet in orbit around the solar--type star 51Peg has been reported by Michel Mayor and Didier Queloz (Geneva Observatory) on October 6th at the 9th Cambridge workshop on "cool stars, stellar systems, and the sun" held at Florence (Italy). ... Recall that the measurements of radial velocity only yield v sin i which in turn gives us M sin i. For most values of i, sin i will be greater than 0.5 and this gives a mass estimate of 0.5 Jupiter masses. ...

... We thank the Swift team for their rapid scheduling of this observation. ... 2455705.20851 V 14.15 0.03 2455707.83079 V 14.10 0.03 2455710.84028 V 13.53 0.02 2455713.64631 V 13.66 0.02 2455714.65479 V 14.11 0.03 2455714.71823 V 14.12 0.02 2455714.78596 V 14.20 0.02 2455717.39593 V 14.37 0.03 2455726.62861 V 14.83 0.04 2455727.16343 V 14.57 0.04 2455730.50586 V 14.57 0.03 2455730.57329 V 14.56 0.03 2455730.70360 V 14.66 0.04 2455738.32865 V 14.00 0.02 2455742.86146 V 14.21 ...