Cloud Atlas: Discovery of Patchy Clouds and High-Amplitude Rotational Modulations in a Young, Extremely Red L-Type Brown Dwarf

Lew, Ben W. P.; Apai, Dániel; Zhou, Yifan; Schneider, Glenn; Burgasser, Adam J.; Karalidi, Theodora; Yang, Hao; Marley, Mark S.; Cowan, Nicolas B.; Bedin, L. R.; Metchev, Stanimir; Radigan, Jacqueline; Lowrance, P.

doi:10.3847/2041-8205/829/2/l32

Cited by 83 publications

(139 citation statements)

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“…We performed the data reduction using the same method as in previous works published by our group (Apai et al 2013;Buenzli et al 2014;Yang et al 2015;Lew et al 2016). The uncertainty level for our spectra after the data reduction is 0.1%-0.3% per spectral bin, measured using the reduced spectra in the range of 1.1-1.69μm to avoid the noise at the edges of the spectra due to the drop in the instrument sensitivity.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…To date, published light curves of various ultracool dwarfs show single or double peaks, whose shapes vary with time, sometimes even within a single rotation (Artigau et al 2009;Radigan et al 2012;Apai et al 2013;Gillon et al 2013;Buenzli et al 2015;Karalidi et al 2015;Metchev et al 2015;Lew et al 2016;Yang et al 2016). These observations are interpreted as single or multiple cloud structures in the atmosphere of brown dwarfs that can evolve at short timescales.…”

Section: Introductionmentioning

confidence: 99%

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Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Manjavacas

Apai

Zhou

et al. 2017

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Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now, rotational spectral modulations have only been seen in three L-type brown dwarfs. We report here the discovery of rotational spectral modulations in LP261-75B, an L6-type intermediate surface gravity companion to an M4.5 star. As a part of the Cloud Atlas Treasury program, we acquired timeresolved Wide Field Camera 3 grism spectroscopy (1.1-1.69 μm) of LP261-75B. We find gray spectral variations with the relative amplitude displaying only a weak wavelength dependence and no evidence for lower-amplitude modulations in the 1.4μm water band than in the adjacent continuum. The likely rotational modulation period is 4.78±0.95hr, although the rotational phase is not well sampled. The minimum relative amplitude in the white light curve measured over the whole wavelength range is 2.41%±0.14%. We report an unusual light curve, which seems to have three peaks approximately evenly distributed in rotational phase. The spectral modulations suggests that the upper atmosphere cloud properties in LP261-75B are similar to two other mid-L dwarfs of typical infrared colors, but differ from that of the extremely red L-dwarf WISE0047.

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Section: Observations and Data Reductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Manjavacas

Apai

Zhou

et al. 2017

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“…The amplitude of variability as a function of wavelength samples the vertical depths of cloud layers (Apai et al 2013), and amplitude spectra have been shown to vary with effective temperature (T ef f ; e.g., Yang et al 2015) and surface gravity (e.g., Lew et al 2016). Wavelength-dependent phase variations in lightcurves have also been observed (Buenzli et al 2012;Biller et al 2013;Yang et al 2016).…”

Section: Introductionmentioning

confidence: 98%

“…Broad-band variability amplitudes are typically <1% in L and T dwarfs, with some dramatic exceptions (Artigau et al 2009;Radigan et al 2012;Gillon et al 2013;Lew et al 2016). Ground-based spectral (e.g., CLOUDS; Goldman et al 2008) and broad-band photometric monitoring surveys (e.g., Bailer-Jones & Mundt 1999;Koen 2003;Radigan et al 2014;Wilson et al 2014) are generally limited to >1-3% relative precision due to telluric atmospheric instabilities (i.e., "red noise") and insufficient numbers of nearby reference stars which can be used to correct time-variable telluric absorption (Bailer-Jones & Lamm 2003).…”

Section: Introductionmentioning

confidence: 99%

Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010

Schlawin¹,

Burgasser

Karalidi³

et al. 2017

ApJ

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L dwarfs exhibit low-level, rotationally-modulated photometric variability generally associated with heterogeneous, cloud-covered atmospheres. The spectral character of these variations yields insight into the particle sizes and vertical structure of the clouds. Here we present the results of a high precision, ground-based, near-infrared, spectral monitoring study of two mid-type L dwarfs that have variability reported in the literature, 2MASS J08354256−0819237 and 2MASS J18212815+1414010, using the SpeX instrument on the Infrared Telescope Facility. By simultaneously observing a nearby reference star, we achieve <0.15% per-band sensitivity in relative brightness changes across the 0.9-2.4µm bandwidth. We find that 2MASS J0835−0819 exhibits marginal ( 0.5% per band) variability with no clear spectral dependence, while 2MASS J1821+1414 varies by up to ±1.5% at 0.9 µm, with the variability amplitude declining toward longer wavelengths. The latter result extends the variability trend observed in prior HST /WFC3 spectral monitoring of 2MASS J1821+1414, and we show that the full 0.9-2.4 µm variability amplitude spectrum can be reproduced by Mie extinction from dust particles with a log-normal particle size distribution with a median radius of 0.24 µm. We do not detect statistically significant phase variations with wavelength. The different variability behavior of 2MASS J0835−0819 and 2MASS J1821+1414 suggests dependencies on viewing angle and/or overall cloud content, underlying factors that can be examined through a broader survey.

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“…However, most recent time-resolved spectroscopic studies are limited to low spectral resolution with a resolving power of ∼100. These observations imposed limits on particle sizes in BD atmospheres (Lew et al 2016) and mapped surface spots and faculae coverage (Burgasser et al 2014;Karalidi et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

Prato

Mawet

2017

ApJ

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Many brown dwarfs (BDs) exhibit photometric variability at levels from tenths to tens of percents. The photometric variability is related to magnetic activity or patchy cloud coverage, characteristic of BDs near the L-T transition. Time-resolved spectral monitoring of BDs provides diagnostics of cloud distribution and condensate properties. However, current time-resolved spectral studies of BDs are limited to low spectral resolution (R∼100) with the exception of the study of Luhman 16 AB at aresolution of 100,000 using the VLT+CRIRES. This work yielded the first map of BD surface inhomogeneity, highlighting the importance and unique contribution of high spectral resolution observations. Here, we report on the time-resolved high spectral resolution observations of a nearby BD binary, 2MASSW J0746425+200032AB. We find no coherent spectral variability that is modulated with rotation. Based on simulations, we conclude that the coverage of a single spot on 2MASSW J0746425 +200032AB is smaller than 1% or 6.25% if spot contrast is 50% or 80% of its surrounding flux, respectively. Future high spectral resolution observations aided by adaptive optics systems can put tighter constraints on the spectral variability of 2MASSW J0746425+200032AB and other nearby BDs.

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Cloud Atlas: Discovery of Patchy Clouds and High-Amplitude Rotational Modulations in a Young, Extremely Red L-Type Brown Dwarf

Cited by 83 publications

References 62 publications

Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010

Time-resolved High Spectral Resolution Observation of 2MASSW J0746425+200032AB

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