Infrared spectroscopic survey of the quiescent medium of nearby clouds. II. Ice formation and grain growth in Perseus and Serpens

Interstellar matter and star formatio

A JWST survey for planetary mass brown dwarfs in IC 348*

We have obtained images of the center of the star-forming cluster IC 348 with the James Webb Space Telescope and have identified brown dwarf candidates based on their photometry and point-like flux profiles. Low-resolution spectroscopy has been performed on four promising candidates, three of which have molecular absorption bands that indicate late spectral types. Among those late-type objects, the brightest is similar to known young L dwarfs while the other two show the so-called 3.4 μm feature that has been previously observed in the diffuse interstellar medium and in the atmospheres of Saturn and Titan, which has been attributed to an unidentified aliphatic hydrocarbon. Those two objects also exhibit features between 1.1 and 2.6 μm that we identify as the overtone and combination bands for that hydrocarbon. After accounting for the hydrocarbon bands, the remaining spectral features are consistent with youth and inconsistent with field dwarfs. Based on the low extinctions of those objects and the strengths of the overtone and combination bands, we conclude that the hydrocarbon resides in their atmospheres rather than in foreground material. Thus, our detections of the 3.4 μm feature are the first in atmospheres outside of the solar system. The presence of this hydrocarbon is not predicted by any atmospheric models of young brown dwarfs. Based on its luminosity and evolutionary models, the faintest new member of IC 348 has an estimated mass of 3–4 MJup, making it a strong contender for the least massive free-floating brown dwarf that has been directly imaged to date

The edge-on protoplanetary disk HH 48 NE: II. Modeling ices and silicates

Stars and planetary system

Infrared spectroscopic survey of the quiescent medium of nearby clouds. II. Ice formation and grain growth in Perseus and Serpens

Interstellar matter and star formatio

The edge-on protoplanetary disk HH 48 NE: I. Modeling the geometry and stellar parameters

Stars and planetary system

Prebiotic Chemistry of Pluto

International audienceWe present the case for the presence of complex organic molecules, such as amino acids and nucleobases, formed by abiotic processes on the surface and in near-subsurface regions of Pluto. Pluto's surface is tinted with a range of non-ice substances with colors ranging from light yellow to red to dark brown; the colors match those of laboratory organic residues called tholins. Tholins are broadly characterized as complex, macromolecular organic solids consisting of a network of aromatic structures connected by aliphatic bridging units (e.g., Imanaka et al.