Related papers: Imaging the water snowline in protostellar envelop…

The physical and chemical conditions within a protoplanetary disk play a crucial role in determining its chemical composition, which is subsequently inherited by any forming planets. To probe these conditions, high-resolution molecular line…

The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays, stellar X-rays and short-lived radionuclides, each of which varies with…

(Abridged*) Models of the young solar nebula assume a hot initial disk with most volatiles are in the gas phase. The question remains whether an actively accreting disk is warm enough to have gas-phase water up to 50 AU radius. No detailed…

Water is an important molecule in the chemical and thermal balance of dense molecular gas, but knowing its history through-out the various stages of the star formation is a fundamental problem. Its molecular deuteration provides us with a…

According to traditional gas-phase chemical models, O2 should be abundant in molecular clouds, but until recently, attempts to detect interstellar O2 line emission with ground- and space-based observatories have failed. Following the…

H$_2$CO ice on dust grains is an important precursor of complex organic molecules (COMs). H$_2$CO gas can be readily observed in protoplanetary disks and may be used to trace COM chemistry. However, its utility as a COM probe is currently…

Much attention has been placed on the dust distribution in protostellar envelopes, but there are still many unanswered questions regarding the structure of the gas. We aim to start identifying the factors that determine the chemical…

Water is essential to our understanding of the planet-formation process and habitability on Earth. Although trace amounts of water are seen across all phases of star and planet formation, the bulk of the water reservoir often goes…

In protoplanetary disks, atomic carbon is expected to originate from the PDR at the disk surface where CO is dissociated by UV photons coming from the stellar, or external interstellar, radiation field. Even though atomic carbon has been…

CO has long been thought to be the best tracer to measure gas masses as it is readily detected at (sub)mm wavelengths in many disks. Inferred gas masses from CO in recent ALMA observations of large samples of disks seem inconsistent with…

We have calculated an evolution of protoplanetary disk from an extensive set of initial conditions using a time-dependent model capable of simultaneously keeping track of the global evolution of gas and water-ice. A number of…

Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel…

We have imaged 15 molecular-line emissions and the dust continuum emission around the Class 0 protostellar source, IRAS 15398-3359, with ALMA. The outflow structure is mainly traced by the H2CO (K_a=0 and 1), CCH, and CS emissions. These…

Ices are the main carriers of volatiles in protoplanetary disks and are crucial to our understanding of the chemistry that ultimately sets the organic composition of planets. The ERS program Ice Age on the JWST follows the ice evolution…

Many astrochemical models of observed CO isotopologue line emission, earlier considered a good proxy measure of H$_2$ and hence disk gas mass, favor large deviations in the carbon and oxygen gas phase abundances and argue that severe gas…

The high spatial and line sensitivity of ALMA opens the possibility of resolving emission from molecules in circumstellar disks. With an understanding of physical conditions under which molecules have high abundance, they can be used as…

M-stars are the most common hosts of planetary systems in the Galaxy. Protoplanetary disks around M-stars thus offer a prime opportunity to study the chemistry of planet-forming environments. We present an ALMA survey of molecular line…

Molecular emission is used to investigate both the physical and chemical properties of protoplanetary disks. Therefore, to accurately derive disk properties, we need a thorough understanding of the behavior of the molecular probes we rely…

[Abridged] The detection of the rotational lines of CO in proto-galaxies in the early Universe provides one of the most promising ways of probing the fundamental physical properties of a galaxy, such as its size, dynamical mass, gas…

Context. This paper discusses the sensitivity of water lines to chemical processes and radiative transfer for the protoplanetary disk around TW Hya. The study focuses on the Herschel spectral range in the context of new line detections with…