We present optical spectroscopy of three brown dwarf candidates identified in the first 1% of the DENIS sky survey. Low resolution spectra from 6430–9150Å show these objects to have similar spectra to the uncertain brown dwarf candidate GD 165B. High resolution spectroscopy shows that one of the objects – DBD 1228-1547 – has a strong 2.3±0.05Å equivalent width absorption line of Li I 6708Å, and...

We present optical spectroscopy of three brown dwarf candidates identified in the first 1% of the DENIS sky survey. Low resolution spectra from 6430–9150Å show these objects to have similar spectra to the brown dwarf candidate GD 165B. High resolution spectroscopy shows that one of the objects – DENIS-P J1228.2-1547 – has a strong 2.3±0.05Å equivalent width absorption line of Li I 6708Å, and is...

Context. Mass accretion rate determinations are fundamental for an understanding of the evolution of pre-main sequence star circumstellar disks. Aims. Magnetospheric accretion models are used to derive values of the mass accretion rates in objects of very different properties, from brown dwarfs to intermediate-mass stars; we test the validity of these models in the brown dwarf regime, where the...

In this contribution, I touch on a subset of our recent efforts in spectral and opacity modeling aimed at improving our understanding of brown dwarfs, L dwarfs, and T dwarfs. I discuss theoretical calculations of the alkali line profiles, newly generated CrH opacities, new evidence for refractory rainout in T dwarfs from optical spectral measurements, and the distinction between brown dwarfs an...

We present the current status of PHOENIX model atmospheres for dwarfs of the spectral type T, typical for older field brown dwarfs and low-mass brown dwarfs. The results are based on new predictions of the CH4 line opacities from theoretical calculations with the STDS software package, extrapolating to transitions from rotational levels up to J = 40. While individual line positions and strength...

Ammonia (NH3) emissions from laying hens are affected by nutrient content of the diet, manure quantity, and manure properties such as moisture content, nitrogen content, and pH. These production traits may vary with strain of the hen. However, limited information is available concerning the effects of laying-hen genetics on manure properties and NH3 emission. This study was conducted to compara...

We present comprehensive experimental line lists of methane (CH4) at high temperatures obtained by recording Fourier transform infrared emission spectra. Calibrated line lists are presented for the temperatures 300–1400◦C at twelve 100◦C intervals spanning the 960–5000 cm−1 (2.0–10.4μm) region of the infrared. This range encompasses the dyad, pentad, and octad regions, i.e., all fundamental vib...