Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-Wavelength Variability Monitoring of Wise J104915.57–531906.1AB

Biller, Beth; Crossfield, Ian J. M.; Mancini, L.; Ciceri, S.; Southworth, J.; Kopytova, T.; Bonnefoy, M.; Deacon, N. R.; Schlieder, Joshua E.; Buenzli, E.; Brandner, W.; Homeier, D.; Freytag, B.; Bailer‐Jones, C. A. L.; Greiner, J.; Henning, Thomas; Goldman, B.

doi:10.1088/2041-8205/778/1/l10

Cited by 113 publications

(135 citation statements)

References 19 publications

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“…With K s ≈ 13.7, it is as bright as PSO J140.2308+45.6487 (=WISEA J092055.41+453855.9) newly classified by Best et al (2013) as a L9.5 dwarf (with signs of spectral variability), which was first photometrically estimated as a mid-L dwarf by Aberasturi et al (2011) and then classified as an L9 and weak binary candidate by Mace et al (2013). Although from our spectrum there are no hints of a possible close companion, WISEA J0647−1546 may also be worth high-resolution imaging observations and variability analysis (see Biller et al 2013;Burgasser et al 2014;Gelino et al 2014).…”

Section: Near-infrared Spectroscopic Classificationmentioning

confidence: 92%

WISEA J064750.85-154616.4: a new nearby L/T transition dwarf

Scholz

Bihain

Storm

2014

A&A

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Aims. Our aim is to detect and classify previously overlooked brown dwarfs in the solar neighbourhood. Methods. We performed a proper motion search among bright sources observed with the Wide-field Infrared Survey Explorer (WISE) that are also seen in the Two Micron All Sky Survey (2MASS). Our candidates appear according to their red J−K s colours as nearby late-L dwarf candidates. Low-resolution near-infrared (NIR) classification spectroscopy in the HK band allowed us to get spectroscopic distance and tangential velocity estimates. Results. We have discovered a new L9.5 dwarf, WISEA J064750.85-154616.4, at a spectroscopic distance of about 14 pc and with a tangential velocity of about 11 km s −1 , typical of the Galactic thin disc population. We have confirmed another recently found L/T transition object at about 10 pc, WISEA J140533.13+835030.7, which we classified as L8 (NIR).

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Section: Near-infrared Spectroscopic Classificationmentioning

confidence: 92%

WISEA J064750.85-154616.4: a new nearby L/T transition dwarf

Scholz

Bihain

Storm

2014

A&A

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“…Additionally, Spitzer monitoring of UCDs indicates that low-level variability is ubiquitous in the 3.6 and 4.5 μm bands, also interpreted as clouds . Many of the IR-variable objects also appear to display significant optical variability, with amplitudes of ∼10%, comparable to the highest amplitude IR variables (Biller et al 2013;Heinze et al 2015).…”

Section: Photometric Variabilitymentioning

confidence: 92%

A Panchromatic View of Brown Dwarf Aurorae

Pineda

Hallinan

Kao

2017

ApJ

118

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Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence, there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. We examine this transition and the prevalence of auroral activity in brown dwarfs through a compilation of multiwavelength surveys of magnetic activity, including radio, X-ray, and optical. We compile the results of those surveys and place their conclusions in the context of auroral emission as a consequence of large-scale magnetospheric current systems that accelerate energetic electron beams and drive the particles to impact the cool atmospheric gas. We explore the different manifestations of auroral phenomena, like Hα, in brown dwarf atmospheres and define their distinguishing characteristics. We conclude that large-amplitude photometric variability in the near-infrared is most likely a consequence of clouds in brown dwarf atmospheres, but that auroral activity may be responsible for long-lived stable surface features. We report a connection between auroral Hα emission and quiescent radio emission in electron cyclotron maser instability pulsing brown dwarfs, suggesting a potential underlying physical connection between quiescent and auroral emissions. We also discuss the electrodynamic engines powering brown dwarf aurorae and the possible role of satellites around these systems both to power the aurorae and seed the magnetosphere with plasma.

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“…Low surface gravity allows cloud species to potentially extend up to lower pressures and higher altitudes compared to the high surface gravity case (Marley et al 2012). In general, for brown dwarfs and free-floating planetary-mass objects, the photosphere in the mid-IR is at lower pressures and higher altitudes than the photosphere in the near-IR (see, e.g., Marley et al 2012;Biller et al 2013a). Thus, the extension of clouds up to lower pressure regions increases the chance of heterogeneous cloud opacity (and hence variability) at the lowpressure levels probed by mid-IR observations.…”

Section: Amplitudesmentioning

confidence: 99%

Simultaneous Multiwavelength Variability Characterization of the Free-floating Planetary-mass Object PSO J318.5−22

Biller

Vos

Buenzli

et al. 2018

Self Cite

109

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We present simultaneous Hubble Space Telescope (HST) WFC3+Spitzer IRAC variability monitoring for the highly variable young (∼20 Myr) planetary-mass object PSO J318.5−22. Our simultaneous HST + Spitzer observations covered approximately two rotation periods with Spitzer and most of a rotation period with the HST. We derive a period of 8.6±0.1 hr from the Spitzer light curve. Combining this period with the measured v i sin for this object, we find an inclination of 56°.2±8°. 1. We measure peak-to-trough variability amplitudes of 3.4%±0.1% for Spitzer Channel 2 and 4.4%-5.8% (typical 68% confidence errors of ∼0.3%) in the near-IR bands (1.07-1.67 μm) covered by the WFC3 G141 prism-the mid-IR variability amplitude for PSO J318.5−22 is one of the highest variability amplitudes measured in the mid-IR for any brown dwarf or planetary-mass object. Additionally, we detect phase offsets ranging from 200°to 210°(typical error of ∼4°) between synthesized near-IR light curves and the Spitzer mid-IR light curve, likely indicating depth-dependent longitudinal atmospheric structure in this atmosphere. The detection of similar variability amplitudes in wide spectral bands relative to absorption features suggests that the driver of the variability may be inhomogeneous clouds (perhaps a patchy haze layer over thick clouds), as opposed to hot spots or compositional inhomogeneities at the top-of-atmosphere level.

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Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-Wavelength Variability Monitoring of Wise J104915.57–531906.1AB

Cited by 113 publications

References 19 publications

WISEA J064750.85-154616.4: a new nearby L/T transition dwarf

WISEA J064750.85-154616.4: a new nearby L/T transition dwarf

A Panchromatic View of Brown Dwarf Aurorae

Simultaneous Multiwavelength Variability Characterization of the Free-floating Planetary-mass Object PSO J318.5−22

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