PHOTOMETRIC VARIABILITY OF THE T2.5 BROWN DWARF SIMP J013656.5+093347: EVIDENCE FOR EVOLVING WEATHER PATTERNS

By É. Artigau, Sandie Bouchard, R. Doyon, D. Lafrèniere. 2009

171 citations recorded by the source corpus.

We report the discovery of a photometric variability in the bright T2.5 brown dwarf (BD) SIMP J013656.57+093347.3. Continuous J-band photometry has been obtained for several hours on four different nights. The light curves show a periodic modulation with a period of ∼2.4 hr, a peak-to-peak amplitude of ∼50 mmag and significant night-to-night evolution. We suggest that the light curve modulation is due to the BD's rotation and that the longer term variations come from surface features evolution and/or differential rotation. We obtained complementary observations over a single night in the J and Ks bands; the object displays correlated photometric variability in both bands, albeit with smaller Ks-band amplitude. The ratio of the Ks and J variability amplitudes puts strong constraints on the physical mechanisms at play. Based on theoretical models of BD atmospheres, our results suggest that the atmosphere of SIMP0136 is comprised of both grain-free and colder (by ∼100 K) grain-bearing cloudy regions. This discovery, and its interpretation, provide a natural explanation of the so-called J-band brightening.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/6f50a43c20767cf2938cd06c2db96f7470b1d675

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In Astronomy and Astrophysics

1. M. Marley
2. Jon Fortney
3. Michael C. Liu
4. T. Dupuy
5. A. Burgasser
6. N. Madhusudhan
7. D. Saumon
8. Adam Burrows

In Computational Mechanics

1. Michael C. Liu
2. M. Marley
3. T. Dupuy
4. D. Saumon
5. I. Neill Reid
6. M. Cushing
7. A. Burgasser
8. K. Luhman

Citations in the corpus

• THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION, (2012, background): “The driving role played by 12Note that these comparisons assume negligible near-IR variability, which is actually unknown for these specific objects but which is generally found to be .0.05 mag for objects of similar spectral type (Koen et al. 2004, 2005; Clarke et al. 2008; Artigau et al. 2009).”
• NEGLECTED CLOUDS IN T AND Y DWARF ATMOSPHERES (2012, background): “However, the recent discovery of highly photometrically variable early T dwarfs suggests that cloud patchiness may indeed play a role (Radigan et al. 2012; Artigau et al. 2009).”
• DISCOVERY OF A BINARY BROWN DWARF AT 2 pc FROM THE SUN (2013, background): “Thus, it may be an attractive target for de- tailed photometric monitoring (e.g., Artigau et al. 2009; Radigan et al. 2012).”
• WEATHER ON OTHER WORLDS. II. SURVEY RESULTS: SPOTS ARE UBIQUITOUS ON L AND T DWARFS (2014, background): “Separately, all L and T dwarf photometric periods measured in high-cadence, intensive monitoring campaigns have been shorter than 9 h (Clarke et al. 2002, 2008; Koen et al. 2005; Artigau et al. 2009, RLJ14).”
• LARGE-AMPLITUDE VARIATIONS OF AN L/T TRANSITION BROWN DWARF: MULTI-WAVELENGTH OBSERVATIONS OF PATCHY, HIGH-CONTRAST CLOUD FEATURES (2012, methodology): “An intriguing possibility is that the long-timescale evolution of the light curve is caused by the differential rotation of a storm system with respect to cloud features at different latitudes (e.g. Artigau et al. 2009).”
• A COMBINED SUBARU/VLT/MMT 1–5 μm STUDY OF PLANETS ORBITING HR 8799: IMPLICATIONS FOR ATMOSPHERIC PROPERTIES, MASSES, AND FORMATION (2011, background): “5+093347 is consistent with grain free, cloudless regions and grain-bearing cloudy regions rotating in and out of view (Artigau et al. 2009).”
• MASSES, RADII, AND CLOUD PROPERTIES OF THE HR 8799 PLANETS (2012, background): “T transition dwarfs that vary in brightness with time with relatively large near-infrared amplitudes (Artigau et al. 2009; Radigan et al. 2012b).”
• On the Cool Side: Modeling the Atmospheres of Brown Dwarfs and Giant Planets (2014, background): “The emergent spectra of many L and T dwarfs are known to vary with time (e.g., Tinney & Tolley 1999; Bailer-Jones & Mundt 1999; Gelino et al. 2002; Artigau et al. 2009; Heinze et al. 2013).”
• HST SPECTRAL MAPPING OF L/T TRANSITION BROWN DWARFS REVEALS CLOUD THICKNESS VARIATIONS (2013, methodology): “The same conclusion was reached by Artigau et al. (2009) for SIMP0136 based on comparison of models by Allard et al. (2003) and Tsuji (2005) to their ground-based ∆J/∆K observations and by Radigan et al. (2012) for 2M2139 through comparison to models by Saumon & Marley (2008).”
• A PATCHY CLOUD MODEL FOR THE L TO T DWARF TRANSITION (2010, background): “The growing evidence for temporal photometric variability at the L to T transition (Artigau et al. 2009; Radigan et al. 2010) supports the plausibility of partial cloudiness being responsible for the change in colors across the transition.”