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Disk in the Circumstellar Envelope of Carbon Mira V Cygni
Strakhov, Ivan A.; Shenavrin, Victor I.; Safonov, Boris S. +2 more
Asymptotic giant branch (AGB) stars are the primary source of dust and complex molecules in the interstellar medium. The determination of outflow parameters is often hindered by the unknown geometry of the circumstellar environment, creating a demand for high-angular resolution observations. We use our near-infrared spectra and photometry of the c…
Detection of Near-infrared Water Ice at the Surface of the (Pre)Transitional Disk of AB Aur: Informing Icy Grain Abundance, Composition, and Size
Pinte, C.; Ménard, F.; Duchêne, G. +17 more
We present near-infrared Large Binocular Telescope LMIRCam imagery of the disk around the Herbig Ae/Be star AB Aurigae. A comparison of the surface brightness at K s (2.16 µm), H2O narrowband (3.08 µm), and $L^{\prime} $ (3.7 µm) allows us to probe the presence of icy grains in this (pre)transitional disk …
SOFIA upGREAT/FIFI-LS Emission-line Observations of Betelgeuse during the Great Dimming of 2019/2020
Harper, Graham M.; Guinan, Edward F.; Fadda, Dario +12 more
We report NASA-DLR SOFIA upGREAT circumstellar [O I] 63.2 µm and [C II] 157.7 µm emission profiles and FIFI-LS [O I] 63.2 µm, [O I] 145.5 µm, and [C II] 157.7 µm fluxes obtained shortly after Betelgeuse's 2019/2020 Great Dimming event. Haas et al. noted a potential correlation between the [O I] 63.2 µm flux and …
Observations of Disequilibrium CO Chemistry in the Coldest Brown Dwarfs
Fortney, Jonathan J.; Marley, Mark S.; Freedman, Richard S. +10 more
Cold brown dwarfs are excellent analogs of widely separated, gas giant exoplanets, and provide insight into the potential atmospheric chemistry and physics we may encounter in objects to be discovered by future direct imaging surveys. We present a low-resolution, R ∼ 300, M-band spectroscopic sequence of seven brown dwarfs with effective temperatu…
High-resolution Optical Spectroscopic Observations of Comet 21P/Giacobini-Zinner in Its 2018 Apparition
Shinnaka, Yoshiharu; Kawakita, Hideyo; Tajitsu, Akito
Comet 21P/Giacobini-Zinner is a peculiar comet from the viewpoints of the chemical and physical properties of its dust grains. We conduct optical high-resolution spectroscopic observations of the comet. The intensity ratios of forbidden oxygen lines (at 557.7, 630.0, and 636.4 nm) and ortho-to-para abundance ratios (OPRs) of water cations (H2…
Searching for Cool Dust. II. Infrared Imaging of The OH/IR Supergiants, NML Cyg, VX Sgr, S Per, and the Normal Red Supergiants RS Per and T Per
Gehrz, Robert D.; Humphreys, Roberta M.; Jones, Terry J. +6 more
New MMT/MIRAC (9-11 µm), SOFIA/FORCAST (11-37 µm), and Herschel/PACS (70 and 160 µm) infrared (IR) imaging and photometry is presented for three famous OH/IR red supergiants (NML Cyg, VX Sgr, and S Per) and two normal red supergiants (RS Per and T Per). We model the observed spectral energy distributions (SEDs) using radiative-tr…
The Double Dust Envelopes of R Coronae Borealis Stars
Evans, A.; Clayton, Geoffrey C.; Matsuura, M. +5 more
The study of extended, cold dust envelopes surrounding R Coronae Borealis (RCB) stars began with their discovery by the Infrared Astronomical Satellite. RCB stars are carbon-rich supergiants characterized by their extreme hydrogen deficiency and their irregular and spectacular declines in brightness (up to 9 mag). We have analyzed new and archival…
GTC/CanariCam Mid-IR Imaging of the Fullerene-rich Planetary Nebula IC 418: Searching for the Spatial Distribution of Fullerene-like Molecules
García-Lario, P.; García-Hernández, D. A.; García-Segura, G. +3 more
We present seeing-limited narrow-band mid-IR GTC/CanariCam images of the spatially extended fullerene-containing planetary nebula (PN) IC 418. The narrow-band images cover the C60 fullerene band at 17.4 µm, the polycyclic aromatic hydrocarbon like (PAH-like) feature at 11.3 µm, the broad 9-13 µm feature, and their adja…
Different Origins or Different Evolutions? Decoding the Spectral Diversity Among C-type Asteroids
Jorda, L.; Lamy, P.; Groussin, O. +15 more
Anhydrous pyroxene-rich interplanetary dust particles (IDPs) have been proposed as surface analogs for about two-thirds of all C-complex asteroids. However, this suggestion appears to be inconsistent with the presence of hydrated silicates on the surfaces of some of these asteroids, including Ceres. Here, we report the presence of enstatite (pyrox…
D/H Ratios on Saturn and Jupiter from Cassini CIRS
Fletcher, L. N.; Lellouch, E.; Irwin, P. G. J. +7 more
We present new measurements of the deuterium abundance on Jupiter and Saturn, showing evidence that Saturn's atmosphere contains less deuterium than Jupiter's. We analyzed far-infrared spectra from the Cassini Composite Infrared Spectrometer to measure the abundance of HD on both giant planets. Our estimate of the Jovian D/H = (2.95 ± 0.55) × 10