Details

Autor(en) / Beteiligte

• Fuda, Nguyen
• Apai, Dániel
• Nardiello, Domenico
• Tan, Xianyu
• Karalidi, Theodora
• Bedin, Luigi Rolly

Titel

Latitude-dependent Atmospheric Waves and Long-period Modulations in Luhman 16 B from the Longest Light Curve of an Extrasolar World

Ist Teil von

• The Astrophysical journal, 2024-04, Vol.965 (2), p.182

Ort / Verlag

Philadelphia: IOP Publishing

Erscheinungsjahr

2024

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• Abstract In this work, we present the longest photometric monitoring of up to 1200 hr of the strongly variable brown dwarf binaries Luhman 16 AB and provide evidence of ±5% variability on a timescale of several to hundreds of hours for this object. We show that short-period rotational modulation around 5 hr ( k = 1 wavenumber) and 2.5 hr ( k = 2 wavenumber) dominate the variability under 10 hr, where the planetary-scale wave model composed of k = 1 and k = 2 waves provides good fits to both the periodograms and light curve. In particular, models consisting of three to four sine waves could explain the variability of the light-curve durations up to 100 hr. We show that the relative range of the k = 2 periods is narrower compared to the k = 1 periods. Using simple models of zonal banding in solar system giants, we suggest that the difference in period range arises from the difference in wind-speed distribution at low and mid-to-high latitudes in the atmosphere. Last, we show that Luhman 16 AB also exhibits long-period ±5% variability, with periods ranging from 15 hr up to 100 hr over the longest monitoring of this object. Our results for the k = 1 and k = 2 waves and long-period evolution are consistent with previous 3D atmosphere simulations, demonstrating that both latitude-dependent waves and slow-varying atmospheric features are potentially present in Luhman 16 AB atmospheres and are a significant contribution to the light-curve modulation over hundreds of rotations.