Gas phase Elemental abundances in Molecular cloudS (GEMS) II. On the quest for the sulphur reservoir in molecular clouds: the HS case.

Context: Sulphur is one of the most abundant elements in the Universe. Surprisingly, sulphuretted molecules are not as abundant as expected in the interstellar medium and the identity of the main sulphur reservoir is still an open question.

Aims: Our goal is to investigate the HS chemistry in dark clouds, as this stable molecule is a potential sulphur reservoir.

Dynamics of cluster-forming hub-filament systems: The case of the high-mass star-forming complex Monoceros R2.

Context: High-mass stars and star clusters commonly form within hub-filament systems. Monoceros R2 (hereafter Mon R2), at a distance of 830 pc, harbors one of the closest such systems, making it an excellent target for case studies.

Aims: We investigate the morphology, stability and dynamical properties of the Mon R2 hub-filament system.

Gas Accretion within the Dust Cavity in AB Aur.

AB Aur is a Herbig Ae star hosting a well-known transitional disk. Because of its proximity and low inclination angle, it is an excellent object to study planet formation. Our goal is to investigate the chemistry and dynamics of the molecular gas component in the AB Aur disk, and its relation with the prominent horseshoe shape observed in continuum mm emission.

Gas phase Elemental abundances in Molecular cloudS (GEMS): I. The prototypical dark cloud TMC 1.

GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3 mm and 2 mm) and the 40m Yebes telescope (1.

Revisiting the case of R Monocerotis: Is CO removed at R < 20 au?.

Context: To our knowledge, R Mon is the only B0 star in which a gaseous Keplerian disk has been detected. However, there is some controversy about the spectral type of R Mon. Some authors propose that it could be a later B8e star, where disks are more common.

Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub.

We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 m, 160 m, 250 m, 350 m, and 500 m by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Space Observatory as part of the imaging survey of OB young stellar objects (HOBYS) Key programme. The data are complemented by SCUBA-2 data in the submillimetre range, and WISE and data in the mid-infrared. In addition, CO data from the IRAM 30-m Telescope are presented, and used for kinematic information.

(sub)Millimeter Emission Lines of Molecules in Born-again Stars.

Context: Born-again stars offer us a unique possibility of studying the evolution of the circumstellar envelope of evolved stars in human timescales. To present, most of the observations of the circumstellar material in these stars have been limited to study the relatively hot gas and dust. In other evolved stars, the emission from rotational transitions of molecules, such as CO, is commonly used to study the cool component of their circumstellar envelopes.

The first CO image: I. Probing the HI/H layer around the ultracompact HII region Mon R2.

The CO reactive ion is thought to be a tracer of the boundary between a HII region and the hot molecular gas. In this study, we present the spatial distribution of the CO rotational emission toward the Mon R2 star-forming region. The CO emission presents a clumpy ring-like morphology, arising from a narrow dense layer around the HII region.