University of Hertfordshire

From the same journal

From the same journal

By the same authors


  • 2001.11015v1

    Accepted author manuscript, 1.67 MB, PDF document

  • Dark Energy Survey Collaboration
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Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 9 Oct 2020


We present the discovery of 255 binary and six multiple system candidates with wide (> 5") separation composed by L or T dwarfs companions to stars, plus nine double brown dwarf systems. The sample of brown dwarf candidates was found in the Dark Energy Survey and the possible stellar companions are from Gaia DR2 and DES data. Our search is based in a common distance criterion with no proper motion information. For the Gaia DR2 stars we estimate distances based on their parallaxes and photometry, using the StarHorse code, while for DES stars, the StarHorse distances were purely photometric for the majority of cases, with a fraction having parallax measurement from Gaia DR2. L and T dwarfs distances are based on empirical templates ranging from L0 to T9. We also compute chance alignment probabilities in order to assess the physical nature of each pair. We find 174 possible pairs with Gaia DR2 primaries with chance alignment probabilities <5%. We also find 85 binary pair candidates with a DES star as a primary, 81 of them with chance alignment probabilities <5%. Only nine candidate systems composed of two brown dwarfs were identified. The sample of multiple systems is made up of five triple systems and one quadruple system. We determine that the typical wide binary fraction over the L and T spectral types is 2-4%. The significant leap provided by this sample will enable constraints on the formation and evolution of L and T dwarfs.


This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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