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We present OVRO Millimeter Array lambda = 3.4 - 1.2 mm dust continuum and spectral line observations of the accretion disk encircling the T Tauri star LkCa 15. The 1.2 mm dust continuum emission is resolved, and gives a minimum diameter of…

To investigate the disk formation and jet launch in protostars is crucial to comprehend the earliest stages of star and planet formation. We aim to constrain the properties of the molecular jet and the disk of the HH 212 protostellar system…

星系天体物理 · 物理学 2015-09-09 L. Podio , C. Codella , F. Gueth , S. Cabrit , R. Bachiller , A. Gusdorf , C. -F. Lee , B. Lefloch , S. Leurini , B. Nisini , M. Tafalla

CO is thought to be the main reservoir of volatile carbon in protoplanetary disks, and thus the primary initial source of carbon in the atmospheres of forming giant planets. However, recent observations of protoplanetary disks point towards…

地球与行星天体物理 · 物理学 2019-06-12 Kamber R. Schwarz , Edwin A. Bergin , L. Ilsedore Cleeves , Ke Zhang , Karin I. Öberg , Geoffrey A. Blake , Dana E. Anderson

JWST is discovering a plethora of species in planet-forming disks around very low-mass stars such as C2H2, C6H6, C4H2, CH3 etc. The column densities of these species retrieved from 0D slab models are very large, e.g. of the order of…

(Abridged) We aim to explore the parameters that influence the mid-infrared emission of C$_2$H$_2$ and H$_2$O, and if the spread observed in $F\rm{_{C_2H_2}}$/$F\rm{_{H_2O}}$ is tracing a variation of the C/O ratio. Our work is based on the…

We develop a new 1D photochemical kinetics code to address stratospheric chemistry and stratospheric heating in hot Jupiters. Here we address optically active S-containing species and CO2 at 1200 < T < 2000 K. HS (mercapto) and S2 are…

地球与行星天体物理 · 物理学 2009-08-10 K. Zahnle , M. S. Marley , R. S. Freedman , K. Lodders , J. J. Fortney

Supermassive black holes power Active Galactic Nuclei (AGN), injecting energy that regulates accretion and shapes host galaxies. We investigate the morphology, excitation, and kinematics of molecular hydrogen (H2) in the inner circumnuclear…

We study the PAH emission from protoplanetary disks. First, we discuss the dependence of the PAH band ratios on the hardness of the absorbed photons and the temperature of the stars. We show that the photon energy together with a varying…

太阳与恒星天体物理 · 物理学 2015-06-04 Ralf Siebenmorgen , Frank Heymann

We present an observational and theoretical study of the primary ionizing agents (cosmic rays and X-rays) in the TW Hya protoplanetary disk. We use a set of resolved and unresolved observations of molecular ions and other molecular species,…

太阳与恒星天体物理 · 物理学 2015-06-23 L. Ilsedore Cleeves , Edwin A. Bergin , Chunhua Qi , Fred C. Adams , Karin I. Oberg

We present arcsecond-scale Submillimeter Array observations of the CO(3-2) line emission from the disks around the young stars HD 163296 and TW Hya at a spectral resolution of 44 m/s. These observations probe below the ~100 m/s turbulent…

太阳与恒星天体物理 · 物理学 2015-05-20 A. Meredith Hughes , David J. Wilner , Sean M. Andrews , Chunhua Qi , Michiel R. Hogerheijde

The presence of asymmetries and substructures in protoplanetary disks, revealed by both dust and gas emission, highlights the potential interplay and the broader connection between chemistry and dynamics in disk evolution. We explore…

We present JWST/MIRI spectra from the Medium-Resolution Spectrometer of IZw18, a nearby dwarf galaxy with a metallicity of $\sim 3$% Solar. Here, we investigate warm molecular hydrogen, H2, observed in spectra extracted in $\sim 120$ pc…

The adsorption of volatile molecules onto dust grain surfaces fundamentally influences dust-related processes, including condensation of gas-phase molecules, dust coagulation, and planet formation in protoplanetary disks. Using advanced…

地球与行星天体物理 · 物理学 2026-03-05 Lile Wang , Feng Long , Haifeng Yang , Ruobing Dong , Shenzhen Xu

We report the detection of quiescent H_2 emission in the v=1-0 S(1) line at 2.12183 um in the circumstellar environment of two classical T Tauri stars, GG Tau A and LkCa 15, in high-resolution (R 60,000) spectra, bringing to four, including…

天体物理学 · 物理学 2009-11-07 J. S. Bary , D. A. Weintraub , J. H. Kastner

We report the first fully sampled maps of the distribution of interstellar CO2 ices, H2O ices and total hydrogen nuclei, as inferred from the 9.7 micron silicate feature, toward the star-forming region Cepheus A East with the IRS instrument…

Observations of submillimeter lines of CO (up to J=6-5), HCO+, HCN (up to J=4-3) and their isotopes from circumstellar disks around low mass pre-main sequence stars are presented. The different line ratios and optical depths indicate that…

天体物理学 · 物理学 2009-11-07 Gerd-Jan van Zadelhoff , Ewine F. van Dishoeck , Wing-Fai Thi , Geoffrey A. Blake

We report the detection of the J=2-1 line of DCO+ in the proto-planetary disk of DM Tau and re-analyze the spectrum covering the 465 GHz transition of HDO in this source, recently published by Ceccarelli et al. (2005). A modelling of the…

天体物理学 · 物理学 2016-08-15 Stéphane Guilloteau , Vincent Piétu , Anne Dutrey , Michel Guélin

Using IRAM 30m, SEST 15m, and Nancay radiotelescopes, we have gathered the 1mm continuum emission, spectra of the J=1--0 CO line and of the HI line at 21cm for two samples of IRAS galaxies. Using these data, we have estimated the HI masses,…

天体物理学 · 物理学 2016-08-30 Paola Andreani , Fabienne Casoli , Maryvonne Gerin

ALMA surveys have shown that CO emission in protoplanetary disks is much fainter than expected. Accordingly, CO-based gas masses and gas/dust ratios are orders of magnitude lower than previously thought. This may be explained either as fast…

太阳与恒星天体物理 · 物理学 2019-10-23 A. Miotello , S. Facchini , E. F. van Dishoeck , P. Cazzoletti , L. Testi , J. P. Williams , M. Ansdell , S. van Terwisga , N. van der Marel

Carbon Monoxide is a commonly used IR/sub-mm tracer of gas in protoplanetary disks. We present an analysis of ultraviolet CO emission in {HST}-COS spectra for 12 Classical T Tauri stars. Several ro-vibrational bands of the CO A^1\Pi -…

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