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Brown dwarfs and planetary-mass companions display rotationally modulated photometric variability, especially those near the L/T transition. This variability is commonly attributed to top-of-atmosphere (TOA) inhomogeneities, with proposed models including patchy thick and thin clouds, planetary-scale jets, or chemical disequilibrium. Surface mapping techniques are powerful tools to probe their atmospheric structures and distinguish between models. One of the most successful methods for stellar surface mapping is Doppler imaging, where the existence of TOA inhomogeneities can be inferred from their varying Doppler shifts across the face of a rotating star. We applied Doppler imaging to the nearest brown dwarf binary WISE 1049AB (also known as Luhman 16AB) using time-resolved, high-resolution spectroscopic observations from Gemini IGRINS, and obtained for the first time H - and K -band simultaneous global weather map for brown dwarfs. Compared to the only previous Doppler map for a brown dwarf in 2014 featuring a predominant mid-latitude cold spot on WISE 1049B and no feature on WISE 1049A, our observations detected persistent spot-like structures on WISE 1049B in the equatorial to mid-latitude regions on two nights, and revealed new polar spots on WISE 1049A. Our results suggest stability of atmospheric features over time-scale of days and possible long-term stable or recurring structures. H - and K -band maps displayed similar structures in and out of CO bands, indicating the cold spots not solely due to chemical hotspots but must involve clouds. Upcoming 30-m extremely large telescopes will enable more sensitive Doppler imaging of dozens of brown dwarfs and even a small number of directly imaged exoplanets. [ABSTRACT FROM AUTHOR]

We present Gemini South/IGRINS observations of the 1060 K T6 dwarf 2MASS J08173001−6155158 with unprecedented resolution (⁠|$R\equiv \lambda /\Delta \lambda =45\, 000$|⁠) and signal-to-noise ratio (S/N > 200) for a late-type T dwarf. We use this benchmark observation to test the reliability of molecular line lists used up-to-date atmospheric models. We determine which spectroscopic regions should be used to estimate the parameters of cold brown dwarfs and, by extension, exoplanets. We present a detailed spectroscopic atlas with molecular identifications across the H and K bands of the near-infrared. We find that water (H2O) line lists are overall reliable. We find the most discrepancies amongst older methane (CH4) line lists, and that the most up-to-date CH4 line lists correct many of these issues. We identify individual ammonia (NH3) lines, a hydrogen sulfide (H2S) feature at 1.5900  |$\mu$| m, and a molecular hydrogen (H2) feature at 2.1218  |$\mu$| m. These are the first unambiguous detections of H2S and H2 absorption features in an extra-solar atmosphere. With the H2 detection, we place an upper limit on the atmospheric dust concentration of this T6 dwarf: at least 500 times less than the interstellar value, implying that the atmosphere is effectively dust-free. We additionally identify several features that do not appear in the model spectra. Our assessment of the line lists is valuable for atmospheric model applications to high-dispersion, low-S/N, high-background spectra, such as an exoplanet around a star. We demonstrate a significant enhancement in the detection of the CH4 absorption signal in this T6 dwarf with the most up-to-date line lists. [ABSTRACT FROM AUTHOR]

7 NNdist proj Distance to nearest neighbor (Mpc) calculated as the projected distance to the nearest neighbor in a cylindrical volume within cz = 500kms -1 of the main object. Callie E. Hood 1, Sheila J. Kannappan 1, David V. Stark 1,2, Ian P. Dell'Antonio 3, Amanda J. Moffett 1,4, Kathleen D. Eckert 1,5, Mark A. Norris 6, and David Hendel 7 1 Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27516, USA 2 KavliInstitute forthePhysicsand MathematicsoftheUniverse (WPI),TheUniversity ofTokyo InstitutesforAdvancedStudy,TheUniversityofTokyo,Kashiwa, Chiba 277-8583, Japan 3 Department of Physics, Brown University, Box 1843, Providence, RI 02912, USA 4 Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37240, USA 5 Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA 6 Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK 7 Department of Astronomy, Columbia University, 550 W 120th Street, New York, NY 10027, USA Received 2020 December 17; revised 2021 March 2; published 2021 April 7 Supporting material: machine-readable table Table 2 in the published article provided incorrect kd-tree nearest neighbor distances calculated using the kd-tree algorithm for all galaxies. The corrected Table 2 in this erratum provides updated kd-tree and projected nearest neighbor distances correctedfortheaforementionederrorsandomittingrs1492,andtheupdatedvaluesdonotchangeanyoftheresultsinthepublished article. [Extracted from the article]