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arxiv: 2606.26411 · v1 · pith:NHWB4W5Enew · submitted 2026-06-24 · 🌌 astro-ph.SR · astro-ph.EP

A Spitzer Space Telescope Exploration Science Program to Search for Y Dwarf Variability

Michael C. Cushing , Jesica L. Trucks , Kevin K. Hardegree-Ullman , Adam J. Burgasser , Sean J. Carey , Jonathan J. Fortney , Christopher R. Gelino , John E. Gizis
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J. Davy Kirkpatrick Sandy Leggett Gregory N. Mace Mark S. Marley Caroline V. Morley
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Pith reviewed 2026-06-26 00:46 UTC · model grok-4.3

classification 🌌 astro-ph.SR astro-ph.EP
keywords Y dwarfsbrown dwarf variabilitySpitzer Space Telescopecondensate cloudsmid-infrared photometryL T Y dwarfsatmospheric variability
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The pith

Spitzer observations of Y dwarfs combined with L and T dwarf data give weak support to condensate cloud structure changes as the driver of brown dwarf mid-infrared variability.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents new 24-hour Spitzer light curves at 3.6 and 4.5 microns for 14 Y dwarfs, repeated after several months, plus two additional objects to complete the Spitzer Y-dwarf variability sample. Variability fractions range from 35 to 75 percent depending on band and epoch, with most light curves stable over months though a few show amplitude changes. When these fractions are merged with an earlier Spitzer survey of L and T dwarfs, the overall trend across spectral types weakly favors the interpretation that variability arises from horizontal or vertical rearrangements of condensate clouds rather than other mechanisms. A reader would care because Y dwarfs are the coldest known brown dwarfs and serve as benchmarks for the atmospheres of directly imaged giant exoplanets.

Core claim

By measuring mid-infrared variability fractions in Y dwarfs and combining them with prior L and T dwarf results, the mid-infrared variability fraction of L, T, and Y dwarfs weakly supports the hypothesis that brown dwarf variability is caused by variations in the horizontal and/or vertical structure of condensate clouds.

What carries the argument

24-hour Spitzer [3.6] and [4.5] photometric light curves used to detect and quantify variability fractions across Y dwarfs.

If this is right

  • Y dwarf variability fractions are comparable in magnitude to those measured for L and T dwarfs.
  • Most Y dwarf light curves remain stable in shape and amplitude over intervals of several months.
  • A subset of Y dwarfs exhibit clear changes in variability amplitude between the two epochs.
  • The combined L-T-Y sample shows a spectral-type dependence consistent with cloud-driven mechanisms.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Atmospheric circulation models that include both cloud patchiness and vertical mixing could be tested directly against the reported amplitude changes.
  • Multi-epoch monitoring longer than 24 hours would help separate rotational modulation from longer-term weather patterns in the coldest objects.
  • The same observational approach could be applied to directly imaged exoplanets that occupy similar temperature ranges.

Load-bearing premise

The 24-hour Spitzer light curves without extra atmospheric modeling or longer time baselines are enough to separate cloud-driven variability from temperature fluctuations or instrumental effects.

What would settle it

If detailed atmospheric models of the same Y dwarfs show that temperature fluctuations alone reproduce the observed light-curve amplitudes and periods while cloud structure changes do not, the cloud-variability interpretation would be ruled out.

Figures

Figures reproduced from arXiv: 2606.26411 by Adam J. Burgasser, Caroline V. Morley, Christopher R. Gelino, Gregory N. Mace, J. Davy Kirkpatrick, Jesica L. Trucks, John E. Gizis, Jonathan J. Fortney, Kevin K. Hardegree-Ullman, Mark S. Marley, Michael C. Cushing, Sandy Leggett, Sean J. Carey.

Figure 1
Figure 1. Figure 1: Normalized IRAC [3.6] (blue) and [4.5] (red) photometry for the sixteen Y dwarfs in our sample. The epoch 1 data is found in the left panel and the epoch 2 data is found in the right panel. For display purposes only, outliers have been removed as described in §3.2.1. Note that the scale of the ordinate is different for [3.6] and [4.5] light curves. 3.2.1. Bayesian Analysis Our Bayesian analysis starts with… view at source ↗
Figure 1
Figure 1. Figure 1: (Continued) joint probability distribution of the model parameters given our N observations d = [d1, d2, d3, · · · , dN ] using Bayes’ theorem p(θ|d) ∝ L(d|θ)p(θ), (6) where p(θ|d) is the posterior distribution, p(θ) is the prior function, and L(d|θ) is the likelihood. We assume that the random variable ϵ follows a normal distribution with a mean of zero and a variance of σ 2 , and so given that the data p… view at source ↗
Figure 2
Figure 2. Figure 2: Epoch 1 periodograms for the 16 Y dwarfs in our sample. The grey dashed lines give the 5% (95% confidence) False Alarm Levels which give the power levels above which we would expect to see power less than 5% of the time under the null hypothesis of pure Gaussian noise (no variable signal). Any object with power in its periodogram above this level is considered variable [PITH_FULL_IMAGE:figures/full_fig_p0… view at source ↗
Figure 3
Figure 3. Figure 3: Epoch 2 periodograms for the 16 Y dwarfs in our sample. The grey dashed lines give the 5% (95% confidence) False Alarm Levels which give the power levels above which we would expect to see power less than 5% of the time under the null hypothesis of pure Gaussian noise (no variable signal). Any object with power in its periodogram above this level is considered variable [PITH_FULL_IMAGE:figures/full_fig_p0… view at source ↗
Figure 4
Figure 4. Figure 4: Posterior distributions for the variability fraction f for each epoch and each band. 68% and 95% central credibility intervals are indicated in light grey and dark grey, respectively [PITH_FULL_IMAGE:figures/full_fig_p013_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Spitzer variability fractions for L and T dwarfs (S. A. Metchev et al. 2015) and the Y dwarfs (this work). The points without error bars are the raw fractions (number of variable objects/total sample) while the points with error bars have been corrected for survey sensitivity limits. The error bars for the L and T dwarfs are 95% confidence limits while the error bars for the Y dwarfs are centered 95% cred￾… view at source ↗
Figure 6
Figure 6. Figure 6: Reproduction of [PITH_FULL_IMAGE:figures/full_fig_p015_6.png] view at source ↗
read the original abstract

We present the results of a Spitzer Space Telescope Exploration Science Program to search for and characterize variability in Y dwarfs. We observed 14 Y dwarfs over a 24 hr period at [3.6] and [4.5] and then repeated the observations a few months later. We add two Y dwarfs, WD 0806-661B and WISE J085510.83-071442.5, that were also observed with Spitzer so that our sample includes all Y dwarfs observed for variability with Spitzer. We infer variability fractions of 59%+-15% and 64%+10%-13% for [3.6], and [4.5], in the first epoch, and 35%+17% -11% and 75%+8% -15% in the second epoch. We also find that Y dwarf Spitzer light curves are generally stable over timescales of months, but in some cases can show clear changes in amplitude. Combining our results with a similar Spitzer survey of L and T dwarfs by Metchev et al. (2015), we find the mid-infrared variability fraction of L, T, and Y dwarfs weakly supports the hypothesis that brown dwarf variability is caused by variations in the horizontal and/or vertical structure of condensate clouds.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript presents Spitzer Space Telescope observations of 16 Y dwarfs (14 from the Exploration Science Program plus WD 0806-661B and WISE J085510.83-071442.5) at [3.6] and [4.5] over 24-hour periods in two epochs separated by months. It reports variability fractions of 59%±15% and 64%+10%/-13% in epoch 1 and 35%+17%/-11% and 75%+8%/-15% in epoch 2, notes general stability over monthly timescales with occasional amplitude changes, and combines the Y-dwarf fractions with the L/T-dwarf survey of Metchev et al. (2015) to conclude that the mid-infrared variability fraction of L, T, and Y dwarfs weakly supports the hypothesis that brown dwarf variability is caused by variations in the horizontal and/or vertical structure of condensate clouds.

Significance. If the reported fractions prove robust, the work supplies a valuable empirical extension of mid-IR variability statistics into the Y-dwarf regime and completes the Spitzer-observed Y-dwarf sample. This observational completeness is a clear strength. The interpretive claim of even weak support for the condensate-cloud hypothesis, however, adds limited new insight because the fractions alone do not discriminate mechanisms.

major comments (2)
  1. [Abstract and results section] Abstract and results: the variability fractions (59%±15% at [3.6] epoch 1, etc.) are presented without any definition of the detection threshold, without an error budget on the individual light curves, and without stating how many objects were excluded from the sample. These omissions are load-bearing for the central reported percentages.
  2. [Abstract and discussion section] Abstract (final sentence) and discussion: the claim that the combined LTY fractions 'weakly supports the hypothesis that brown dwarf variability is caused by variations in the horizontal and/or vertical structure of condensate clouds' is not justified by the data. No forward modeling of cloud patchiness, no comparison to alternative mechanisms (temperature fluctuations, magnetic spots, or instrumental effects), and no quantification of false-positive rates are provided, so the fractions remain mechanism-agnostic.
minor comments (1)
  1. [Abstract] Abstract: error notation is inconsistent ('59%+-15%' versus '+10%-13%'); adopt a uniform format for symmetric and asymmetric uncertainties.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading and constructive comments. We respond to each major comment below.

read point-by-point responses

  1. Referee: [Abstract and results section] Abstract and results: the variability fractions (59%±15% at [3.6] epoch 1, etc.) are presented without any definition of the detection threshold, without an error budget on the individual light curves, and without stating how many objects were excluded from the sample. These omissions are load-bearing for the central reported percentages.

    Authors: We agree that the abstract and results section should explicitly define the detection threshold, summarize the error budget, and confirm the sample composition. We will revise these sections to include the missing details from the methods analysis. revision: yes

  2. Referee: [Abstract and discussion section] Abstract (final sentence) and discussion: the claim that the combined LTY fractions 'weakly supports the hypothesis that brown dwarf variability is caused by variations in the horizontal and/or vertical structure of condensate clouds' is not justified by the data. No forward modeling of cloud patchiness, no comparison to alternative mechanisms (temperature fluctuations, magnetic spots, or instrumental effects), and no quantification of false-positive rates are provided, so the fractions remain mechanism-agnostic.

    Authors: We agree that the fractions alone are mechanism-agnostic and that the claim of even weak support for condensate clouds is not justified without modeling or comparisons to alternatives. We will revise the abstract and discussion to remove this interpretive statement. revision: yes

Circularity Check

0 steps flagged

No circularity: purely observational fractions with external citation

full rationale

The paper reports measured variability detection rates from 24-hour Spitzer [3.6] and [4.5] light curves on 14 Y dwarfs (plus two additional objects) across two epochs, then combines the resulting fractions (59%±15%, 64%+10%−13%, etc.) with the independent Metchev et al. (2015) L/T survey to state that the combined mid-IR variability fraction “weakly supports” a cloud-structure hypothesis. No equations, fitted parameters, ansatzes, or derivations are present. The Metchev citation is to an external team and is used only for sample extension, not as a load-bearing uniqueness theorem or self-referential justification. The central claim is therefore an empirical summary rather than a reduction of any result to its own inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review; no free parameters, axioms, or invented entities are stated or derivable from the provided text.

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Reference graph

Works this paper leans on

63 extracted references · 51 canonical work pages · 1 internal anchor

  1. [1]

    S., & Marley , M

    Ackerman , A. S., & Marley , M. S. 2001, title Precipitating Condensation Clouds in Substellar Atmospheres , , 556, 872

    2001

  2. [2]

    S., et al

    Apai , D., Karalidi , T., Marley , M. S., et al. 2017, title Zones, spots, and planetary-scale waves beating in brown dwarf atmospheres , Science, 357, 683, 10.1126/science.aam9848

    work page doi:10.1126/science.aam9848 2017

  3. [3]

    Bailer-Jones , C. A. L. 2005, in ESA Special Publication, Vol. 560, 13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, ed. F. Favata, G. A. J. Hussain, & B. Battrick , 429

    2005

  4. [4]

    Bailer-Jones , C. A. L. 2012, title A Bayesian method for the analysis of deterministic and stochastic time series , , 546, A89, 10.1051/0004-6361/201220109

    work page doi:10.1051/0004-6361/201220109 2012

  5. [5]

    Bailer-Jones , C. A. L., & Mundt , R. 2001, title Variability in ultra cool dwarfs: Evidence for the evolution of surface features , , 367, 218, 10.1051/0004-6361:20000416

    work page doi:10.1051/0004-6361:20000416 2001

  6. [6]

    2014, title The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs , , 31, 43, 10.1017/pasa.2014.38

    Bailey , J. 2014, title The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs , , 31, 43, 10.1017/pasa.2014.38

    work page doi:10.1017/pasa.2014.38 2014

  7. [7]

    Baluev , R. V. 2008, title Assessing the statistical significance of periodogram peaks , , 385, 1279, 10.1111/j.1365-2966.2008.12689.x

    work page doi:10.1111/j.1365-2966.2008.12689.x 2008

  8. [8]

    Biller , B. 2017, title The time domain for brown dwarfs and directly imaged giant exoplanets: the power of variability monitoring , The Astronomical Review, 13, 1, 10.1080/21672857.2017.1303105

    work page doi:10.1080/21672857.2017.1303105 2017

  9. [9]

    V., et al

    Buenzli , E., Apai , D., Morley , C. V., et al. 2012, title Vertical Atmospheric Structure in a Variable Brown Dwarf: Pressure-dependent Phase Shifts in Simultaneous Hubble Space Telescope-Spitzer Light Curves , , 760, L31, 10.1088/2041-8205/760/2/L31

    work page doi:10.1088/2041-8205/760/2/l31 2012

  10. [10]

    J., Marley , M

    Burgasser , A. J., Marley , M. S., Ackerman , A. S., et al. 2002, title Evidence of Cloud Disruption in the L/T Dwarf Transition , , 571, L151, 10.1086/341343

    work page doi:10.1086/341343 2002

  11. [11]

    Crossfield , I. J. M. 2014, title Doppler imaging of exoplanets and brown dwarfs , , 566, A130, 10.1051/0004-6361/201423750

    work page doi:10.1051/0004-6361/201423750 2014

  12. [12]

    Cushing , M. C. 2014, in Astrophysics and Space Science Library, Vol. 401, 50 Years of Brown Dwarfs, ed. V. Joergens , 113, 10.1007/978-3-319-01162-2_7

    work page doi:10.1007/978-3-319-01162-2_7 2014

  13. [13]

    C., Marley, M

    Cushing , M. C., Marley , M. S., Saumon , D., et al. 2008, title Atmospheric Parameters of Field L and T Dwarfs , , 678, 1372, 10.1086/526489

    work page doi:10.1086/526489 2008

  14. [14]

    C., Kirkpatrick , J

    Cushing , M. C., Kirkpatrick , J. D., Gelino , C. R., et al. 2011, title The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE) , , 743, 50, 10.1088/0004-637X/743/1/50

    work page doi:10.1088/0004-637x/743/1/50 2011

  15. [15]

    C., Hardegree-Ullman , K

    Cushing , M. C., Hardegree-Ullman , K. K., Trucks , J. L., et al. 2016, title The First Detection of Photometric Variability in a Y Dwarf: WISE J140518.39+553421.3 , , 823, 152, 10.3847/0004-637X/823/2/152

    work page doi:10.3847/0004-637x/823/2/152 2016

  16. [16]

    C., Schneider , A

    Cushing , M. C., Schneider , A. C., Kirkpatrick , J. D., et al. 2021, title An Improved Near-infrared Spectrum of the Archetype Y Dwarf WISEP J182831.08+265037.8 , , 920, 20, 10.3847/1538-4357/ac12cb

    work page doi:10.3847/1538-4357/ac12cb 2021

  17. [17]

    M., Wright , E

    Cutri , R. M., Wright , E. L., Conrow , T., et al. 2013, title Explanatory Supplement to the AllWISE Data Release Products , , Tech. rep

    2013

  18. [18]

    J., Liu , M

    Dupuy , T. J., Liu , M. C., & Leggett , S. K. 2015, title Discovery of a Low-luminosity, Tight Substellar Binary at the T/Y Transition , , 803, 102, 10.1088/0004-637X/803/2/102

    work page doi:10.1088/0004-637x/803/2/102 2015

  19. [19]

    L., Luhman , K

    Esplin , T. L., Luhman , K. L., Cushing , M. C., et al. 2016, title Photometric Monitoring of the Coldest Known Brown Dwarf with the Spitzer Space Telescope , , 832, 58, 10.3847/0004-637X/832/1/58

    work page doi:10.3847/0004-637x/832/1/58 2016

  20. [20]

    doi:10.1086/422843 , Eprint =

    Fazio , G. G., Hora , J. L., Allen , L. E., et al. 2004, title The Infrared Array Camera (IRAC) for the Spitzer Space Telescope , , 154, 10, 10.1086/422843

    work page doi:10.1086/422843 2004

  21. [21]

    and Lang, Dustin and Goodman, Jonathan , year=

    Foreman-Mackey , D., Hogg , D. W., Lang , D., & Goodman , J. 2013, title emcee: The MCMC Hammer , , 125, 306, 10.1086/670067

    work page doi:10.1086/670067 2013

  22. [22]

    2000, in Astronomical Society of the Pacific Conference Series, Vol

    Gelino , C., & Marley , M. 2000, in Astronomical Society of the Pacific Conference Series, Vol. 212, From Giant Planets to Cool Stars, ed. C. A. Griffith & M. S. Marley , 322

    2000

  23. [23]

    R., Marley , M

    Gelino , C. R., Marley , M. S., Holtzman , J. A., Ackerman , A. S., & Lodders , K. 2002, title L Dwarf Variability: I-Band Observations , , 577, 433

    2002

  24. [24]

    E., Burgasser , A

    Gizis , J. E., Burgasser , A. J., Berger , E., et al. 2013, title Kepler Monitoring of an L Dwarf I. The Photometric Period and White Light Flares , , 779, 172, 10.1088/0004-637X/779/2/172

    work page doi:10.1088/0004-637x/779/2/172 2013

  25. [25]

    O., & Corbally , J., C

    Gray , R. O., & Corbally , J., C. 2009, Stellar Spectral Classification

    2009

  26. [26]

    W., Bovy , J., & Lang , D

    Hogg , D. W., Bovy , J., & Lang , D. 2010, title Data analysis recipes: Fitting a model to data , ArXiv e-prints. 1008.4686

    Pith/arXiv arXiv 2010

  27. [27]

    W., Foreman-Mackey D., 2018, @doi [The Astrophysical Journal Supplement Series] 10.3847/1538-4365/aab76e , 236, 11

    Hogg , D. W., & Foreman-Mackey , D. 2018, title Data Analysis Recipes: Using Markov Chain Monte Carlo , The Astrophysical Journal Supplement Series, 236, 11, 10.3847/1538-4365/aab76e

    work page doi:10.3847/1538-4365/aab76e 2018

  28. [28]

    Kirkpatrick , J. D. 2005, title New Spectral Types L and T , , 43, 195, 10.1146/annurev.astro.42.053102.134017

    work page doi:10.1146/annurev.astro.42.053102.134017 2005

  29. [29]

    D., Gelino , C

    Kirkpatrick , J. D., Gelino , C. R., Cushing , M. C., et al. 2012, title Further Defining Spectral Type ''Y'' and Exploring the Low-mass End of the Field Brown Dwarf Mass Function , , 753, 156, 10.1088/0004-637X/753/2/156

    work page doi:10.1088/0004-637x/753/2/156 2012

  30. [30]

    D., Martin , E

    Kirkpatrick , J. D., Martin , E. C., Smart , R. L., et al. 2019, title Preliminary Trigonometric Parallaxes of 184 Late-T and Y Dwarfs and an Analysis of the Field Substellar Mass Function into the Planetary Mass Regime , , 240, 19. 1812.01208

    Pith/arXiv arXiv 2019

  31. [31]

    R., Leggett , S

    Knapp , G. R., Leggett , S. K., Fan , X., et al. 2004, title Near-Infrared Photometry and Spectroscopy of L and T Dwarfs: The Effects of Temperature, Clouds, and Gravity , , 127, 3553, 10.1086/420707

    work page doi:10.1086/420707 2004

  32. [32]

    2007, title The Gemini Deep Planet Survey , , 670, 1367, 10.1086/522826

    Lafreni \`e re , D., Doyon , R., Marois , C., et al. 2007, title The Gemini Deep Planet Survey , , 670, 1367, 10.1086/522826

    work page doi:10.1086/522826 2007

  33. [33]

    K., Cushing , M

    Leggett , S. K., Cushing , M. C., Hardegree-Ullman , K. K., et al. 2016, title Observed Variability at 1 and 4 m in the Y0 Brown Dwarf WISEP J173835.52+273258.9 , , 830, 141, 10.3847/0004-637X/830/2/141

    work page doi:10.3847/0004-637x/830/2/141 2016

  34. [34]

    Luhman , K. L. 2014, title Discovery of a \ 250 K Brown Dwarf at 2 pc from the Sun , , 786, L18, 10.1088/2041-8205/786/2/L18

    work page doi:10.1088/2041-8205/786/2/l18 2014

  35. [35]

    L., Burgasser , A

    Luhman , K. L., Burgasser , A. J., & Bochanski , J. J. 2011, title Discovery of a Candidate for the Coolest Known Brown Dwarf , , 730, L9, 10.1088/2041-8205/730/1/L9

    work page doi:10.1088/2041-8205/730/1/l9 2011

  36. [36]

    L., Burgasser , A

    Luhman , K. L., Burgasser , A. J., Labb \'e , I., et al. 2012, title Confirmation of One of the Coldest Known Brown Dwarfs , , 744, 135, 10.1088/0004-637X/744/2/135

    work page doi:10.1088/0004-637x/744/2/135 2012

  37. [37]

    L., Tremblin , P., Alves de Oliveira , C., et al

    Luhman , K. L., Tremblin , P., Alves de Oliveira , C., et al. 2024, title JWST/NIRSpec Observations of the Coldest Known Brown Dwarf , , 167, 5, 10.3847/1538-3881/ad0b72

    work page doi:10.3847/1538-3881/ad0b72 2024

  38. [38]

    Mace , G. N. 2015, in Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Vol. 18, 18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, 997--1012. 1408.4379

    Pith/arXiv arXiv 2015

  39. [39]

    2000, in Astronomical Society of the Pacific Conference Series, Vol

    Marley , M. 2000, in Astronomical Society of the Pacific Conference Series, Vol. 212, From Giant Planets to Cool Stars, ed. C. A. Griffith & M. S. Marley , 152

    2000

  40. [40]

    A., Heinze , A., Apai , D., et al

    Metchev , S. A., Heinze , A., Apai , D., et al. 2015, title Weather on Other Worlds. II. Survey Results: Spots are Ubiquitous on L and T Dwarfs , , 799, 154, 10.1088/0004-637X/799/2/154

    work page doi:10.1088/0004-637x/799/2/154 2015

  41. [41]

    2002, title Activity in Very Cool Stars: Magnetic Dissipation in Late M and L Dwarf Atmospheres , , 571, 469, 10.1086/339911

    Mohanty , S., Basri , G., Shu , F., Allard , F., & Chabrier , G. 2002, title Activity in Very Cool Stars: Magnetic Dissipation in Late M and L Dwarf Atmospheres , , 571, 469, 10.1086/339911

    work page doi:10.1086/339911 2002

  42. [42]

    V., Fortney, J

    Morley , C. V., Fortney , J. J., Marley , M. S., et al. 2012, title Neglected Clouds in T and Y Dwarf Atmospheres , , 756, 172, 10.1088/0004-637X/756/2/172

    work page doi:10.1088/0004-637x/756/2/172 2012

  43. [43]

    V., Marley , M

    Morley , C. V., Marley , M. S., Fortney , J. J., & Lupu , R. 2014, title Spectral Variability from the Patchy Atmospheres of T and Y Dwarfs , , 789, L14, 10.1088/2041-8205/789/1/L14

    work page doi:10.1088/2041-8205/789/1/l14 2014

  44. [44]

    A., & Cavanaugh , J

    Neath , A. A., & Cavanaugh , J. E. 2012, title The Bayesian information criterion: background, derivation, and applications, Wiley Interdisciplinary Reviews: Computational Statistics, 4, 199

    2012

  45. [45]

    2014, title Strong Brightness Variations Signal Cloudy-to-clear Transition of Brown Dwarfs , , 793, 75, 10.1088/0004-637X/793/2/75

    Radigan , J., Lafreni \`e re , D., Jayawardhana , R., & Artigau , E. 2014, title Strong Brightness Variations Signal Cloudy-to-clear Transition of Brown Dwarfs , , 793, 75, 10.1088/0004-637X/793/2/75

    work page doi:10.1088/0004-637x/793/2/75 2014

  46. [46]

    A., et al

    Rajan , A., Patience , J., Wilson , P. A., et al. 2015, title The brown dwarf atmosphere monitoring (BAM) project - II. Multi-epoch monitoring of extremely cool brown dwarfs , , 448, 3775, 10.1093/mnras/stv181

    work page doi:10.1093/mnras/stv181 2015

  47. [47]

    T., Megeath , S

    Reach , W. T., Megeath , S. T., Cohen , M., et al. 2005, title Absolute Calibration of the Infrared Array Camera on the Spitzer Space Telescope , , 117, 978, 10.1086/432670

    work page doi:10.1086/432670 2005

  48. [48]

    D., & Marley , M

    Robinson , T. D., & Marley , M. S. 2014, title Temperature Fluctuations as a Source of Brown Dwarf Variability , , 785, 158, 10.1088/0004-637X/785/2/158

    work page doi:10.1088/0004-637x/785/2/158 2014

  49. [49]

    J., Karalidi , T., Gizis , J

    Schlawin , E., Burgasser , A. J., Karalidi , T., Gizis , J. E., & Teske , J. 2017, title Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010 , , 849, 163, 10.3847/1538-4357/aa90b8

    work page doi:10.3847/1538-4357/aa90b8 2017

  50. [50]

    C., Cushing , M

    Schneider , A. C., Cushing , M. C., Kirkpatrick , J. D., et al. 2015, title Hubble Space Telescope Spectroscopy of Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer , , 804, 92, 10.1088/0004-637X/804/2/92

    work page doi:10.1088/0004-637x/804/2/92 2015

  51. [51]

    Friedman and Lawrence C

    Schwarz, G. 1978, title Estimating the Dimension of a Model, Ann. Statist., 6, 461, 10.1214/aos/1176344136

    work page doi:10.1214/aos/1176344136 1978

  52. [52]

    C., Leggett , S

    Stephens , D. C., Leggett , S. K., Cushing , M. C., et al. 2009, title The 0.8-14.5 m Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity , , 702, 154. 0906.2991

    Pith/arXiv arXiv 2009

  53. [53]

    S., Chabrier , G., et al

    Tremblin , P., Amundsen , D. S., Chabrier , G., et al. 2016, title Cloudless Atmospheres for L/T Dwarfs and Extrasolar Giant Planets , , 817, L19, 10.3847/2041-8205/817/2/L19

    work page doi:10.3847/2041-8205/817/2/l19 2016

  54. [54]

    S., Mourier , P., et al

    Tremblin , P., Amundsen , D. S., Mourier , P., et al. 2015, title Fingering Convection and Cloudless Models for Cool Brown Dwarf Atmospheres , , 804, L17, 10.1088/2041-8205/804/1/L17

    work page doi:10.1088/2041-8205/804/1/l17 2015

  55. [55]

    2005, title Dust in the Photospheric Environment

    Tsuji , T. 2005, title Dust in the Photospheric Environment. III. A Fundamental Element in the Characterization of Ultracool Dwarfs , , 621, 1033, 10.1086/427747

    work page doi:10.1086/427747 2005

  56. [56]

    VanderPlas , J. T. 2018, title Understanding the Lomb─Scargle Periodogram , The Astrophysical Journal Supplement Series, 236, 16, 10.3847/1538-4365/aab766

    work page internal anchor Pith review doi:10.3847/1538-4365/aab766 2018

  57. [57]

    M., Biller , B

    Vos , J. M., Biller , B. A., Bonavita , M., et al. 2019, title A search for variability in exoplanet analogues and low-gravity brown dwarfs , , 483, 480, 10.1093/mnras/sty3123

    work page doi:10.1093/mnras/sty3123 2019

  58. [58]

    Westphal , J. A. 1969, title Observations of localised 5-micron radiation from Jupiter , , 157, L63, 10.1086/180386

    work page doi:10.1086/180386 1969

  59. [59]

    A., Rajan , A., & Patience , J

    Wilson , P. A., Rajan , A., & Patience , J. 2014, title The brown dwarf atmosphere monitoring (BAM) project. I. The largest near-IR monitoring survey of L and T dwarfs , , 566, A111, 10.1051/0004-6361/201322995

    work page doi:10.1051/0004-6361/201322995 2014

  60. [60]

    Witte , S., Helling , C., Barman , T., Heidrich , N., & Hauschildt , P. H. 2011, title Dust in brown dwarfs and extra-solar planets. III. Testing synthetic spectra on observations , , 529, A44, 10.1051/0004-6361/201014105

    work page doi:10.1051/0004-6361/201014105 2011

  61. [61]

    S., et al

    Yang , H., Apai , D., Marley , M. S., et al. 2016, title Extrasolar Storms: Pressure-dependent Changes in Light-curve Phase in Brown Dwarfs from Simultaneous HST and Spitzer Observations , , 826, 8, 10.3847/0004-637X/826/1/8

    work page doi:10.3847/0004-637x/826/1/8 2016

  62. [62]

    R., Mart \' n , E

    Zapatero Osorio , M. R., Mart \' n , E. L., Bouy , H., et al. 2006, title Spectroscopic Rotational Velocities of Brown Dwarfs , , 647, 1405, 10.1086/505484

    work page doi:10.1086/505484 2006

  63. [63]

    Zhang , X., & Showman , A. P. 2014, title Atmospheric Circulation of Brown Dwarfs: Jets, Vortices, and Time Variability , , 788, L6, 10.1088/2041-8205/788/1/L6

    work page doi:10.1088/2041-8205/788/1/l6 2014