The GALAH Survey: Lithium-strong KM dwarfs

Research output: Contribution to journalReview article

Abstract

Identifying and characterizing young stars in the Solar neighbourhood is essential to find and describe planets in the early stages of their evolution. This work seeks to identify nearby young stars showing a lithium 6708 Å absorption line in the GALAH survey. A robust, data-driven approach is used to search for corresponding templates in the pool of 434 215 measured dwarf spectra in the survey. It enables a model-free search for best-matching spectral templates for all stars, including M dwarfs with strong molecular absorption bands. 3147 stars have been found to have measurable lithium: 1408 G and 892 K0-K5 dwarfs (EW(Li) > 0.1 Å), 335 K5-K9 (>0.07 Å) and 512 M0-M4 dwarfs (>0.05 Å). Stars with such lithium features are used to investigate the possibility of searching for young stars above the main sequence based merely on their parallaxes and broad-band photometry. The selection of young stars above the main sequence is highly effective for M dwarfs, moderately effective for K dwarfs and ineffective for G dwarfs. Using a combination of the lithium information and the complete 6D kinematics from Gaia and GALAH, 305 new candidate moving group members have been found, 123 of which belong to the Scorpius-Centaurus association, 36 to the Pleiades and 25 to the Hyades clusters.

Details

Authors
  • GALAH Collaboration
  • M. Zerjal
  • M. J. Ireland
  • T. Nordlander
  • J. Lin
  • S. Buder
  • L. Casagrande
  • K. Åotar
  • G. De Silva
  • J. Horner
  • S. Martell
  • G. Traven
  • T. Zwitter
Organisations
External organisations
  • Australian National University
  • Max Planck Institute for Astronomy
  • University of Ljubljana
  • University of Sydney
  • University of New South Wales
  • Heidelberg University
  • Australian Astronomical Observatory
  • University of Southern Queensland
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Astronomy, Astrophysics and Cosmology

Keywords

  • stars: abundances, stars: late-type, stars: pre-main-sequence
Original languageEnglish
Pages (from-to)4591-4600
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume484
Issue number4
Publication statusPublished - 2019
Publication categoryResearch
Peer-reviewedYes