English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We aimed to assess the accuracy of the Gaia teff and logg estimates asderived with current models and observations. We assessed the validity ofseveral inference techniques for deriving the physical parameters of ultra-cooldwarf stars. We used synthetic spectra derived from ultra-cool dwarf models toconstruct (train) the regression models. We derived the intrinsic uncertaintiesof the best inference models and assessed their validity by comparing theestimated parameters with the values derived in the bibliography for a sampleof ultra-cool dwarf stars observed from the ground. We estimated the totalnumber of ultra-cool dwarfs per spectral subtype, and obtained values that canbe summarised (in orders of magnitude) as 4 objects in the M5-L0 range,600 objects between L0 and L5, 30 objects between L5 and T0, and 10 objectsbetween T0 and T8. A bright ultra-cool dwarf (with teff=2500 K and \logg=3.5will be detected by Gaia out to approximately 220 pc, while for teff=1500 K(spectral type L5) and the same surface gravity, this maximum distance reducesto 10-20 pc. The RMSE of the prediction deduced from ground-based spectra ofultra-cool dwarfs simulated at the Gaia spectral range and resolution, and fora Gaia magnitude G=20 is 213 K and 266 K for the models based on k-nearestneighbours and Gaussian process regression, respectively. These are totalerrors in the sense that they include the internal and external errors, withthe latter caused by the inability of the synthetic spectral models (used forthe construction of the regression models) to exactly reproduce the observedspectra, and by the large uncertainties in the current calibrations of spectraltypes and effective temperatures.

Properties of ultra-cool dwarfs with Gaia. An assessment of the accuracy for the temperature determination