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Evolution of Dust and Ice Features around FU Orionis Objects

Quanz, S. P.; Henning, Th.; van Boekel, R. +5 more

We present spectra for a sample of 14 FUors and two T Tauri stars observed with Spitzer or ISO. Based on the appearance of the 10 µm silicate feature, we define two categories of FUors. Objects showing the silicate feature in absorption (Category 1) are still embedded in a circumstellar envelope. The shape of the silicate bands is in good ag…

Carbonates in Space: The Challenge of Low-Temperature Data

Mutschke, H.; Henning, Th.; Posch, Th. +1 more

Carbonates have repeatedly been discussed as possible carriers of stardust emission bands. However, the band assignments proposed so far were mainly based on room-temperature powder transmission spectra of the respective minerals. Since very cold calcite grains have been claimed to be present in protostars and in planetary nebulae (PNs) such as NG…

Far-Infrared Detection of H₂D⁺ toward Sgr B2

Cernicharo, J.; Goicoechea, J. R.; Polehampton, E.

We report on the first far-IR detection of H₂D⁺, using the Infrared Space Observatory, in the line of sight toward Sgr B2 in the Galactic center. The transition at λ=126.853 µm connecting the ground level of o-H₂D⁺, 1_1,1, with the 2_1,2 level at 113 K is observed in absorption …