Discovery of Brown Dwarfs mining the 2MASS and SDSS databases
Date:
27 Dec 2024 08:31:05
Publisher:
The GAVO DC team
Description:
Brown dwarfs are objects occupying the gap between the least massive
stars and the most massive planets. They are intrinsically faint
objects so their detection is not straighforward and, in fact, was
almost impossible until the advent of global surveys at deep optical
and near-infrared bands like SDSS, 2MASS or DENIS among others. We
propose here to mine the 2MASS-PSC and SDSS-DR9 databases to identify
T-type brown dwarfs through an appropriate combination of colours in
the optical and the infra-red, an approach that perfectly fits into
the Virtual Observatory.
Identifying Brown Dwarf candidates in 2MASS and SDSS
Date:
27 Dec 2024 08:31:02
Publisher:
The GAVO DC team
Description:
This tutorial is a comprehensive scientific usecase in which brown
dwarf candidates in 2MASS and SDSS are identyfied. The surveys are
queried using ADQL, and unncertainties in the data are solved with
TOPCAT and Aladin.
The Fifth Catalogue of Nearby Stars (CNS5) aims to provide the most
volume-complete sample of stars in the solar neighbourhood. The CNS5
is compiled based on trigonometric parallaxes from Gaia EDR3 and
Hipparcos, and supplemented with astrometric data from Spitzer and
ground-based surveys carried out in the infrared. The CNS5 catalogue
is statistically complete down to 19.7 mag in G-band and 11.8 mag in
W1-band absolute magnitudes, corresponding to a spectral type of L8.
Continuous updates of observational data for nearby stars from all
sources were collected and evaluated. For all known stars in the 25 pc
sphere around the Sun, the best values of positions in space,
velocities, and magnitudes in different filters are presented.
The Ultracool Dwarf Companion Catalogue consists of 278 multiple
systems, 32 of which are newly discovered, each with at least one
spectroscopically confirmed Ultracool Dwarf, within a 100 pc
volume-limited sample. This catalogue is compiled using the Gaia
Catalogue of Nearby Stars for stellar primaries and the Gaia Ultracool
Dwarf Sample for low-mass companions and includes 241 doubles, 33
triples, and 4 higher-order systems established from positional,
proper motion, and parallax constraints.