Monday, 1 December 2025

Substellar Astrophysics meeting in Tordesillas, Spain

 



Substellar science has emerged in the last few decades as new branch of Astrophysics that connects Stars, Exoplanets and the Solar System. The advent of new surveys such as Euclid and Rubin LSST is poised to increase the numbers of known substellar objects by more than an order of magnitude, while the James Webb Telescope is providing new details about their properties. Rapid advances in observational capabilities have spurred the development of a new generation of theoretical models, now reaching unprecedented levels of accuracy and physical completeness.

This meeting will bring together researchers interested in Substellar science with special emphasis on exploiting the wealth of data provided by Euclid and complementing it with other surveys and follow-up observations.

The conference is supported by the European Research Council Advanced grant nicknamed Substellar.

A total eclipse of the Sun will take place during the conference (August 12, 2026).

The proceedings of the conference will be formally published as part of the conference series of Astronomische Nachrichten.

 More information at the conference website. 

Program highlights

Key themes include:
  • Detection methods (Searching methods, astrometry, photometry, spectroscopy)
  • Confirmation of UCD candidates
  • Atmospheric properties of UCD's
  • UCD in connection with Milky Way
  • Multiplicity, planetary systems, disks
  • Substellar luminosity and mass functions
  • Connection with exoplanets
  • Synergies of Euclid and other surveys
  • Big data, machine learning for substellar science
  • Prospects for Exolife in Substellar Worlds
  • Theory of UCD's (atmospheric and evolutionary models, microphysics)

Scientific Organizing Committee

  • Eduardo Martin (chair)
  • Maruša Žerjal (co-chair)
  • Nikola Vitas (co-chair)
  • Patricia Cruz
  • Pin-Gao Gu
  • Nuria Huélamo
  • Nicolas Lodieu
  • Koraljka Mužić
  • Ngoc Phan
  • Annie Robin
  • Johannes Sahlmann
  • Kun Wang

Invited speakers

  • Khalid Barkaoui, Instituto de Astrofísica de Canarias, Tenerife, Spain
  • David Barrado, Centro de Astrobiología, Madrid, Spain
  • Beth Biller, Royal Observatory, Edinburgh, UK
  • Clemence Fontanive, Royal Observatory, Edinburgh, UK
  • Kevin Luhman, Pennsylvania State University, USA
  • Elena Manjavacas, Space Telescope Science Institute, USA
  • Javier Olivares, UNED, Madrid, Spain
  • Antonio Pérez Garrido, Universidad Politécnica de Cartagena, Spain
  • Rafael Rebolo, Instituto de Astrofísica de Canarias, Tenerife, Spain
  • Céline Reylé, Observatoire de Besançon, France
  • Richard Smart, Ossevatorio Astrofisico di Torino, INAF, Italy
  • Enrique Solano, Centro de Astrobiología, Madrid, Spain
  • Xianyu Tan, Shanghai Jiao Tong University, China
  • Ramarao Tata, Ohio University, USA
  • Maria Rosa Zapatero Osorio, Centro de Astrobiología, Madrid, Spain
  • Jun-Yan Zhang, Western University, Ontario, Canada

Wednesday, 2 April 2025

A photometric search for ultracool dwarfs in the Euclid Deep Fields

 

A new paper from Euclid Q1, is just out on arxiv. I’m particularly happy to be part of!

In this work, led by Maruša Žerjal (my collaborator at the IAC and the SUBSTELLAR project), we explored what Euclid can already tell us about the population of ultracool dwarfs. Using a remarkably simple photometric selection based on the very red Euclid ($I_\mathrm{E}-Y_\mathrm{E}$) colour, we identified 5306 new ultracool-dwarf candidates in the three Euclid Deep Fields, ranging from late-M to late-T dwarfs. Around 1200 are L and T dwarfs, and 546 objects are spectroscopically confirmed.

Euclid was designed primarily for cosmology, but its combination of deep optical and near-infrared photometry and spectroscopy makes it an extraordinary machine for finding and characterising the faintest members of the stellar and substellar populations.

And Q1 is only a tiny taste of what is coming. We find roughly 100 UCDs per square degree, which suggests that the final Euclid Wide Survey could contain at least 1.4 million ucd candidates, including around 300 000 L dwarfs and thousands of T dwarfs.

These estimates come from deliberately strict selection criteria that favour purity over completeness, so they are essentially a lower limit. Millions of ultracool dwarfs waiting in the Euclid data, exciting times ahead!