Atmospheric molecular blobs shape up circumstellar envelopes of AGB stars.

During their thermally pulsing phase, asymptotic giant branch (AGB) stars eject material that forms extended dusty envelopes. Visible polarimetric imaging found clumpy dust clouds within two stellar radii of several oxygen-rich stars. Inhomogeneous molecular gas has also been observed in multiple emission lines within several stellar radii of different oxygen-rich stars, including W Hya and Mira.

Detection of vibrationally excited HCN and HCN in IRC+10216 .

Observations of IRC +10216 with the Yebes 40m telescope between 31 and 50 GHz have revealed more than 150 unidentified lines. Some of them can be grouped into a new series of 26 doublets, harmonically related with integer quantum numbers ranging from =54 to 80. The separation of the doublets increases systematically with , i.

The abundance of S- and Si-bearing molecules in O-rich circumstellar envelopes of AGB stars.

Aims: We aim to determine the abundances of SiO, CS, SiS, SO, and SO in a large sample of oxygen-rich asymptotic giant branch (AGB) envelopes covering a wide range of mass loss rates to investigate the potential role that these molecules could play in the formation of dust in these environments.

Methods: We surveyed a sample of 30 oxygen-rich AGB stars in the mm band using the IRAM 30m telescope. We performed excitation and radiative transfer calculations based on the large velocity gradient (LVG) method to model the observed lines of the molecules and to derive their fractional abundances in the observed envelopes.

Discovery of two new magnesium-bearing species in IRC+10216: MgCN and MgCH.

We report on the detection of two series of harmonically related doublets in IRC +10216. From the observed frequencies, the rotational constant of the first series is = 1380.888 MHz and that of the second series is = 1381.

Discovery of the first Ca-bearing molecule in space: CaNC.

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)×10 cm.