相关论文: Observations of Disequilibrium CO Chemistry in the…

Almost all planetary atmospheres are affected by disequilibrium chemical processes. In this paper we introduce our recently developed Chemical Kinetic Model (\texttt{ChemKM}). We show that the results of our HD189733b model are in good…

Brown dwarfs bridge the gap between the stellar and planetary mass regimes. Evolving from conditions very similar to the lowest-mass stars, the atmospheres of older brown dwarfs closely resemble those expected in close-in extrasolar giant…

The atmospheres of brown dwarfs orbiting in close proximity to their parent white dwarf represent some of the most extreme irradiated environments known. Understanding their complex dynamical mechanisms pushes the limits of theoretical and…

The last few years has seen a dramatic increase in the number of exoplanets known and in the range of methods for characterising their atmospheric properties. At the same time, new discoveries of increasingly cooler brown dwarfs have pushed…

We have obtained spatially resolved near-infrared spectroscopy of the Venus nightside on 15 nights over three observing seasons. We use the depth of the CO absorption band at 2.3 microns to map the two-dimensional distribution of CO across…

We investigate variations in the strengths of three molecular bands, CH4 at 3.3 um, CO at 4.6 um and CO2 at 4.2 um, in 16 brown dwarf spectra obtained by AKARI. Spectral features are examined along the sequence of source classes from L1 to…

WISE J085510.83-071442.5 (hereafter WISE 0855-0714) is the coldest known brown dwarf (~250 K) and the fourth closest known system to the Sun (2.2 pc). It has been previously detected only in the J band and two mid-IR bands. To better…

We present a deep near-infrared image of the newly discovered brown dwarf WISE J085510.83-071442.5 (W0855) using the FourStar imager at Las Campanas Observatory. Our detection of J3=24.8+0.33 -0.53 (J_MKO=25.0+0.33-0.53) at 2.6sigma -- or…

Interferometric radius measurements provide a direct probe of the fundamental parameters of M dwarfs, but is within reach for only a limited sample of nearby, bright stars. We use interferometrically-measured radii, bolometric luminosities,…

Brown dwarfs lack nuclear fusion and cool with time; the coldest known have an effective temperature below 500 K, and are known as Y dwarfs. We present a James Webb Space Telescope (JWST) photometric dataset of Y dwarfs: twenty-three were…

The physical state of cold cloud clumps has a great impact on the process and efficiency of star formation and the masses of the forming stars inside these objects. The sub-millimetre survey of the Planck space observatory and the…

A large suite of 228 atmospheric retrievals is performed on a curated sample of 19 brown dwarfs spanning the L0 to T8 spectral types using the open-source Helios-r2 retrieval code, which implements the method of short characteristics for…

We calculate detailed chemical abundance profiles for a variety of brown dwarf and extrasolar giant planet atmosphere models, focusing in particular on Gliese 229B, and derive the systematics of the changes in the dominant reservoirs of the…

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

The atmospheric pressure-temperature profiles for transiting giant planets cross a range of chemical transitions. Here we show that the particular shape of these irradiated profiles for warm giant planets below 1300 K lead to striking…

As part of a larger search of Wide-field Infrared Survey Explorer (WISE) data for cool brown dwarfs with effective temperatures less than 1000 K, we present the discovery of three new cool brown dwarfs with spectral types later than T7.…

T-type brown dwarfs present an opportunity to explore atmospheres teeming with molecules such as H2O, CH4 and NH3, which exhibit a wealth of absorption features in the mid-infrared. With JWST, we can finally explore this chemistry in…

Brown dwarfs -- substellar bodies more massive than planets but not massive enough to initiate the sustained hydrogen fusion that powers self-luminous stars -- are born hot and slowly cool as they age. As they cool below about 2,300 K,…

We present an analysis of brown dwarf model spectra in the mid-infrared spectral region (5 - 20 microns), in anticipation of data obtained with the Space Infrared Telescope Facility. The mid-infrared spectra of brown dwarfs are in several…

The formation mechanisms and chemical compositions of brown dwarfs likely span a diverse range. If they are formed predominantly in isolation by gravitational collapse like dwarf stars then their compositions might follow those of dwarf…