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The nucleosynthesis production of fluorine (F) is still a matter of debate. Asymptotic giant branch (AGB) stars are one of the main candidates for F production. However, their contribution to the total F budget is not fully known due to the lack of observations. In this paper, we report the detection of aluminium monofluoride (AlF) line emission, one of the two main carriers of F in the gas-phase in the outflow of evolved stars, towards five nearby oxygen-rich (M-type) AGB stars. We studied the Atacama large millimetre/sub-millimetre array (ALMA) observations of AlF (v = 0, J = 4-3, 9-8, 10-9, and 15-14) and (v = 1, J = 7-6) line emission towards o Ceti, and (v = 0, J = 7-6 and 15-14) lines towards R Leo. We also report a tentative detection of AlF (v = 0, J = 7-6) line in IK Tau, (v = 0, J = 15-14) line towards R Dor, and (v = 0, J = 7-6 and J = 15-14) lines in W Hya. From spatially resolved observations, we estimated the AlF emitting region with a radius ∼11R∗ for o Ceti and ∼9R∗ for R Leo. From population diagram analysis, we report the AlF column densities of ∼5.8 × 1015 cm-2 and ∼3 × 1015 cm-2 for o Ceti and R Leo, respectively, within these regions. For o Ceti, we used the C18O (v = 0, J = 3-2) observations to estimate the H2 column density of the emitting region. We found a fractional abundance of fAIF/H2 ∼ (2.5 ± 1.7) × 10-8. This gives a lower limit on the F budget in o Ceti and is compatible with the solar F budget fF/H2 = (5 ± 2) × 10-8. For R Leo, a fractional abundance fAIF/H2 = (1.2 ± 0.5) × 10-8 is estimated. For other sources, we cannot precisely determine the emitting region based on the available data. Assuming an emitting region with a radius of ∼11R∗ and the rotational temperatures derived for o Ceti and R Leo, we crudely approximated the AlF column density to be ∼(1.2-1.5) × 1015 cm-2 in W Hya, ∼(2.5-3.0) × 1014 cm-2 in R Dor, and ∼(0.6-1.0) × 1016 cm-2 in IK Tau. These result in fractional abundances within a range of fAIF/H2 ∼ (0.1 - 4) × 10-8

We present a set of Atacama Large Millimeter/submillimeter Array (ALMA) continuum and molecular line emission maps at ~1 mm wavelengths of OH 231.8+4.2. This is a well studied bipolar nebula around an asymptotic giant branch (AGB) star that is key in investigations of the origin of the remarkable changes in nebular morphology and kinematics during the short transition from the AGB to the planetary nebula (PN) phase. The excellent angular resolution of our maps (~20 mas ¿ 30 au) allows us to scrutinize the central nebular regions of OH 231.8+4.2, which hold the clues to unravel how this iconic object assembled its complex nebular architecture. We report, for the first time for this object and others of its kind (i.e.,pre-PN with massive bipolar outflows), the discovery of a rotating circumbinary disk selectively traced by NaCl, KCl, and H2O emission lines. This represents the first detection of KCl in an oxygen-rich (O-rich) AGB circumstellar envelope (CSE). The rotating disk, of a radius of ~30 au, lies at the base of a young bipolar wind traced by SiO and SiS emission (referred to as the SS-outflow), which also presents signs of rotation at its base. The NaCl equatorial structure is characterised by a mean rotation velocity of Vrot ~ 4 km s¿1 and extremely low expansion speeds, Vexp ~ 3 km s¿1. The SS-outflow has predominantly expansive kinematics, characterized by a constant radial velocity gradient of ~65km s¿1 arcsec¿1 at its base. Beyond r ~ 350 au, the gas in the SS-outflow continues its radial flow at a constant terminal speed of Vexp ~ 16 km s¿1. Our continuum maps reveal a spatially resolved dusty disk-like structure perpendicular to the SS-outflow, with the NaCl, KCl, and H2O emission arising from the surface layers of the disk. Within the disk, we also identify an unresolved point continuum source, which likely represents the central Mira-type star QX Pup enshrouded by a ~3 R* component of hot, (~1400 K) freshly formed dust. The point source is slightly o

We present new interferometer molecular observations of R Leo taken at 1.2 mm with the Atacama Large Millimeter Array with an angular resolution up to 0'. 026. These observations permitted us to resolve the innermost envelope of this star, which revealed a complex structure that involves extended continuum emission and molecular emission showing a non-radial gas velocity distribution. This molecular emission displays prominent red-shifted absorptions located immediately in front of the star, which are typical footprints of material infall. This emission also shows lateral gas motions compatible with a torus-like structure.

We report on the detection of calcium isocyanide, CaNC, in the carbon-rich evolved star IRC+10216. We derived a column density for this species of (2 ± 0.5) × 1011 cm−2 . Based on the observed line profiles and the modelling of its emission through the envelope, the molecule has to be produced in the intermediate and outer layers of the circumstellar envelope where other metal-isocyanides have previously been found in this source. The abundance ratio of CaNC relative to MgNC and FeCN is '1/60 and '1, respectively. We searched for the species CaF, CaCl, CaC, CaCCH, and CaCH3 for which accurate frequency predictions are available. Only upper limits have been obtained for these molecules.

We present continuum and molecular line emission ALMA observations of OH 231.8+4.2, a well studied bipolar nebula around an asymptotic giant branch (AGB) star. The high-angular resolution (~0.¿¿2¿0.¿¿3) and sensitivity of our ALMA maps provide the most detailed and accurate description of the overall nebular structure and kinematics of this object to date. We have identified a number of outflow components previously unknown. Species studied in this work include 12CO, 13CO, CS, SO, SO2, OCS, SiO, SiS, H3O+, Na37Cl, and CH3OH. The molecules Na37Cl and CH3OH are first detections in OH 231.8+4.2, with CH3OH being also a first detection in an AGB star. Our ALMA maps bring to light the totally unexpected position of the mass-losing AGB star (QX Pup) relative to the large-scale outflow. QX Pup is enshrouded within a compact (¿60 AU) parcel of dust and gas (clump S) in expansion (Vexp ~ 5¿7 km s¿1) that is displaced by ~ 0.¿¿6 to the south of the dense equatorial region (or waist) where the bipolar lobes join. Our SiO maps disclose a compact bipolar outflow that emerges from QX Pup¿s vicinity. This outflow is oriented similarly to the large-scale nebula but the expansion velocities are about ten times lower (Vexp ¿ 35 km s¿1). We deduce short kinematical ages for the SiO outflow, ranging from ~50¿80 yr, in regions within ~150 AU, to ~400¿500 yr at the lobe tips (~3500 AU). Adjacent to the SiO outflow, we identify a small-scale hourglass-shaped structure (mini-hourglass) that is probably made of compressed ambient material formed as the SiO outflow penetrates the dense, central regions of the nebula. The lobes and the equatorial waist of the mini-hourglass are both radially expanding with a constant velocity gradient (Vexp ¿ r). The mini-waist is characterized by extremely low velocities, down to ~1 km s¿1 at ~150 AU, which tentatively suggest the presence of a stable structure. The spatio-kinematics of the large-scale, high-velocity lobes (HV lobes), and the dense equatoria