Monitoring Hα Emission from the Wide-orbit Brown-dwarf Companion FU Tau B

Ya Lin Wu*, Yu Chi Cheng, Li Ching Huang, Brendan P. Bowler, Laird M. Close, Wei Ling Tseng, Ning Chen, Da Wei Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Monitoring mass accretion onto substellar objects provides insights into the geometry of the accretion flows. We use the Lulin One-meter Telescope to monitor Hα emission from FU Tau B, a ∼19 M Jup brown-dwarf companion at 5.″7 (719 au) from the host star, for six consecutive nights. This is the longest continuous Hα monitoring for a substellar companion near the deuterium-burning limit. We aim to investigate if accretion near the planetary regime could be rotationally modulated as suggested by magnetospheric accretion models. We find tentative evidence that Hα mildly varies on hourly and daily timescales, though our sensitivity is not sufficient to definitively establish any rotational modulation. No burst-like events are detected, implying that accretion onto FU Tau B is overall stable during the time baseline and sampling windows over which it was observed. The primary star FU Tau A also exhibits Hα variations over timescales from minutes to days. This program highlights the potential of monitoring accretion onto substellar objects with small telescopes.

Original languageEnglish
Article number143
JournalAstronomical Journal
Issue number4
Publication statusPublished - 2023 Oct 1

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Monitoring Hα Emission from the Wide-orbit Brown-dwarf Companion FU Tau B'. Together they form a unique fingerprint.

Cite this