Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools

TL;DR

This study used Virtual Observatory tools to identify 32 bright blue high proper motion objects across the sky, including new discoveries of hot subdwarfs, white dwarfs, and early-type stars, enhancing the catalog of such objects.

Contribution

The paper presents a novel all-sky search method combining multiple catalogues and tools to discover new bright blue high proper motion objects, including five objects reported for the first time.

Findings

Assembled a sample of 32 bright blue high proper motion objects.

Discovered five objects reported for the first time.

Confirmed the hot subdwarf nature of one new object, Albus 5.

Abstract

With available Virtual Observatory tools, we looked for new bright blue high proper motion objects in the entire sky: white dwarfs, hot subdwarfs, runaway OB stars, and early-type stars in nearby young moving groups. We performed an all-sky cross-match between the optical Tycho-2 and near-infrared 2MASS catalogues with Aladin, and selected objects with proper motions >50mas/yr and colours Vt-Ks<-0.5mag with TOPCAT. We also collected multi-wavelength photometry, constructed the spectral energy distributions and estimated effective temperatures from fits to atmospheric models with VOSA for the most interesting targets. We assembled a sample of 32 bright blue high proper motion objects, including ten sdO/B subdwarfs, nine DA white dwarfs, five young early-type stars (two of which are runaway stars), two blue horizontal branch stars, one star with poor information, and five objects reported for the first time in this work. These last five objects have magnitudes Bt~11.0-11.6mag, effective temperatures ~24,000-30,000K, and are located in the region of known white dwarfs and hot subdwarfs in a reduced proper motion-colour diagram. We confirmed the hot subdwarf nature of one of the new objects, Albus 5, with public far-ultraviolet spectroscopic data obtained with FUSE.