We calculate theoretical isochrones, in a consistent way, for five filters in the atmospheric window between 1.9μm and 2.5μm, K, K , Ks, F205W, and F222M, using the Padova stellar evolutionary models by Girardi et al. Even when displayed in the same Vega magnitude system, the near-infrared colors of the same isochrone can differ by up to 0.18 mag at its bright end, depending on the filter. We p...

Hipparcos parallaxes and proper motions have made it possible to construct Hertzsprung-Russell (HR) diagrams of nearby clusters with unprecedented accuracy. The standard deviation of high fidelity non-binary non-variable stars about a model stellar evolution isochrone in the Hyades cluster is about 0.04 magnitudes. We use this deviation to estimate an upper limit on the scatter in metallicities...

Abstract We present new isochrone fits to the colour–magnitude diagrams of Galactic globular clusters NGC 6362 and 6723. utilize 22 26 photometric filters for 6723, respectively, from ultraviolet mid-infrared using data sets Hubble Space Telescope, Gaia, unWISE, other sources. use models isochrones Dartmouth Stellar Evolution Database (DSED) Bag Tracks Isochrones (BaSTI) α-enhanced [α/Fe] = +0....

We estimate here the age of one of the prototypes of the Beta Pic-like stars, Fomalhaut, based on the properties of its common proper motion companion Gl879. By combining constraints derived from the lithium abundance, rotational velocity, HR diagram position, and coronal activity we conclude that the age for Gl879, and hence the age for Fomalhaut, is 200±100 Myr. This age estimate agrees quite...