We present a photometric investigation on HB, RGB, and MSTO stars in ω Cen=NGC 5139. The center of the cluster was covered with a mosaic of F435W, F625W, and F658N band data collected with HST ACS. The outer reaches were covered with a mosaic of U-, B-, V-, and I-band data collected with the 2.2 m ESO/MPI telescope. The final catalog includes ~1.7

The Ca II infrared triplet is one of the few magnetically sensitive chromospheric lines available for ground-based observations. We present spectropolarimetric observations of the 8498 and 8542 Å lines in a quiet Sun region near a decaying active region and compare the results with a simulation of the lines in a high plasma-β regime. Cluster

A 52' × 52' field in the Lupus Galactic plane was observed with the ANU 1m telescope for 53 nights during 2005 and 2006 in a search for transiting Hot Jupiter planets. A total of 2200 images were obtained. We have sampled 120,000 stars via differential photometry, of which ˜26,000 have sufficient photometric accuracy (≤ 2.5 %) with which to perform

This table shows the main Cluster characteristics (1 data file).

We present the results of a deep optical-near-infrared (optical-NIR) multi-epoch survey covering 2.5 deg2 of the Pleiades open star cluster to search for new very low-mass brown dwarf members. A significant (~5 yr) epoch difference exists between the optical (CFH12k I-, Z-band) and NIR (UKIRT WFCAM J-band) observations. We construct I, I - Z and Z

Many ground-based photometric surveys are now under way, and five of them have been successful at detecting transiting exoplanets. Nevertheless, detecting transiting planets has turned out to be much more challenging than initially anticipated. Transit surveys have learnt that an overwhelming number of false positives and confusion scenarios