New ultracool dwarf neighbours within 20 pc from<i>Gaia</i>DR2

Scholz, R.‐D.

doi:10.1051/0004-6361/201937373

Cited by 16 publications

(8 citation statements)

References 113 publications

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“…Our survey for the lowest-mass NYMG members is incomplete due to Gaia EDR3 only being sensitive out to 20-30 pc for mid-L members (Scholz 2020). The completeness of individual NYMGs must differ as their mean distances and ages vary widely.…”

Section: Population Statistics and Survey Limitmentioning

confidence: 98%

Low-mass members of nearby young stellar moving groups from Gaia EDR3

Lee,

Song,

Murphy

2022

Preprint

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Gaia EDR3 offers greatly improved kinematics for nearby objects, including members of nearby young stellar moving groups (NYMGs). In this study, we aim to identify low-mass NYMG members (spectral types of M0 to mid-L) in Gaia EDR3. We calculated spatio-kinematic membership probabilities utilising a Bayesian membership probability calculation scheme developed in our previous study. We evaluated stellar youth primarily based on colour-magnitude diagram positions. Combining spatiokinematic membership assessment and youth evaluation, we identified ∼2900 low-mass NYMG candidate members including ∼700 previously claimed members. In the set of ∼2200 new candidate members, ∼550 appear to be young based on NUV brightness. Our pilot spectroscopic study with WiFeS on the ANU 2.3-m telescope observed 78 candidates, with 79 per cent confirmed as members. Using our new member sample, we estimated an isochronal age of the 𝛽 Pictoris Moving Group. The mean age (∼10 Myr), which is around half the age of recent estimates, suggests either a truly younger age of the 𝛽 Pictoris Moving Group or inaccuracies in contemporary isochrones. As the main results of this study, we provide lists of newly confirmed and candidate low-mass NYMG members.

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Section: Population Statistics and Survey Limitmentioning

confidence: 98%

Low-mass members of nearby young stellar moving groups from Gaia EDR3

Lee,

Song,

Murphy

2022

Preprint

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“…Based on photometric data and the star's Gaia DR2 parallax (59.733 ± 0.088 mas, [44]), ref. [45] estimated a spectral type of M6.5 ± 1.5, while Sebastian et al [5] derived a mass of 0.102 ± 0.003 M ⊙ , a radius of 0.123 ± 0.015 R ⊙ , an effective temperature of 2829 ± 104 K, and an estimated spectral type of M6.0 ± 1.0. In 2021, the parallax was revised to be 59.701 ± 0.043 mas by the Gaia EDR3 release [46].…”

Section: Discovery Speculoos Photometrymentioning

confidence: 99%

An Earth-sized exoplanet ripe for emission spectroscopy with JWST in orbit around a nearby ultracool dwarf star

Gillon,

Pedersen,

Rackham

et al. 2023

Preprint

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The JWST space telescope has the potential to measure the emission spectrum of a highly irradiated exoplanet as small as the Earth, especially if it transits a very nearby and cold star similar in size to Jupiter. Such ‘ultracool dwarf stars’ are frequent in the solar neighborhood, but their planetary population remain extremely poorly studied. Indeed, only one transiting planetary system had been discovered around an ultracool dwarf star so far, TRAPPIST-1, and none of its seven planets is irradiated enough to make spectroscopic characterization by occultation emission spectroscopy possible with JWST. Here we present the discovery by the SPECULOOS project of an Earth-sized planet on a 17 hr orbit around an M6.5-type dwarf star 16.8 parsecs away. Thanks to its large irradiation (∼16 times the Earth’s), the infrared brightness, and Jupiter-like size of its host star, emission spectroscopy is possible with JWST, enabling the study of the planet’s atmospheric composition and/or surface mineralogy

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“…The full sky coverage and high-precision observations of Gaia offer the means of uncovering nearby UCDs through astrometric rather than purely photometric selection (Reylé 2018;Smart et al 2019;Scholz 2020). Gaia provides a large homogeneous sample.…”

Section: Stellar To Substellar Boundarymentioning

confidence: 99%

Gaia Early Data Release 3

Smart

Sarro

Rybizki

et al. 2021

A&A

226

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Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use. Methods. Theselection of objects within 100 pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100 pc is included in the catalogue. Results. We have produced a catalogue of 331 312 objects that we estimate contains at least 92% of stars of stellar type M9 within 100 pc of the Sun. We estimate that 9% of the stars in this catalogue probably lie outside 100 pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun. Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.

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New ultracool dwarf neighbours within 20 pc fromGaiaDR2

Cited by 16 publications

References 113 publications

Low-mass members of nearby young stellar moving groups from Gaia EDR3

Low-mass members of nearby young stellar moving groups from Gaia EDR3

An Earth-sized exoplanet ripe for emission spectroscopy with JWST in orbit around a nearby ultracool dwarf star

Gaia Early Data Release 3

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