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.

New molecular species at redshift = 0.89.

We present the first detections of CHSH, CH, CN, HCOOH, CHCHCN, and HCN in an extragalactic source. Namely the spiral arm of a galaxy located at z = 0.89 on the line of sight to the radio-loud quasar PKS 1830-211.

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.

IRC +10216 as a spectroscopic laboratory: improved rotational constants for SiC, its isotopologues, and SiC.

This work presents a detailed analysis of the laboratory and astrophysical spectral data available for SiC, SiC,SiC, SiCC, and SiC. New data on the rotational lines of these species between 70 and 350 GHz have been obtained with high spectral resolution (195 kHz) with the IRAM 30m telescope in the direction of the circumstellar envelope IRC +10216. Frequency measurements can reach an accuracy of 50 kHz for features observed with a good signal to noise ratio.

Time-dependent molecular emission in IRC+10216.

Context: The variability in IRC+10216, the envelope of the asymptotic giant branch (AGB) star CW Leo, has attracted increasing attention in recent years. Studying the details of this variability in the molecular emission required a systematic observation program.

Aims: We aim to reveal and characterize the periodical variability of the rotational lines from several molecules and radicals in IRC+10216, and to compare it with previously reported IR variability.

IRC +10 216 in 3-D: morphology of a TP-AGB star envelope.

During their late pulsating phase, AGB stars expel most of their mass in the form of massive dusty envelopes, an event that largely controls the composition of interstellar matter. The envelopes, however, are distant and opaque to visible and NIR radiation: their structure remains poorly known and the mass-loss process poorly understood. Millimeter-wave interferometry, which combines the advantages of longer wavelength, high angular resolution and very high spectral resolution is the optimal investigative tool for this purpose.

Discovery of methyl silane and confirmation of silyl cyanide in IRC +10216.

We report the discovery in space of methyl silane, CHSiH, from observations of ten rotational transitions between 80 and 350 GHz ( from 4 to 16) with the IRAM 30 m radio telescope. The molecule was observed in the envelope of the C-star IRC +10216. The observed profiles and our models for the expected emission of methyl silane suggest that the it is formed in the inner zones of the circumstellar envelope, 1-40 , with an abundance of (0.

The growth of carbon chains in IRC +10216 mapped with ALMA.

Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation of carbon chains in the C-star envelope IRC +10216, where the polymerization of acetylene and hydrogen cyanide induced by ultraviolet photons can drive the formation of linear carbon chains of increasing length.

Molecular shells in IRC+10216: tracing the mass loss history

Thermally-pulsating AGB stars provide three-fourths of the matter returned to the interstellar medium. The mass and chemical composition of their ejecta largely control the chemical evolution of galaxies. Yet, both the mass loss process and the gas chemical composition remain poorly understood.

The interstellar chemistry of HCO isomers.

We present the detection of two HCO isomers, propynal and cyclopropenone, toward various starless cores and molecular clouds, together with upper limits for the third isomer propadienone. We review the processes controlling the abundances of HCO isomers in interstellar media showing that the reactions involved are gas-phase ones. We show that the abundances of these species are controlled by kinetic rather than thermodynamic effects.

Hints of a rotating spiral structure in the innermost regions around IRC +10216.

The Atacama Large Millimeter/submillimeter Array (ALMA) is allowing us to study the innermost regions of the circumstellar envelopes of evolved stars with precision and sensitivity. Key processes in the ejection of matter and dust from these objects occur in their inner zones. In this work, we present sub-arcsecond interferometric maps of transitions of metal-bearing molecules towards the prototypical C-rich evolved star IRC +10216.

Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si-C bonds.

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order.

Discovery of interstellar ketenyl (HCCO), a surprisingly abundant radical.

We have conducted radioastronomical observations of 9 dark clouds with the IRAM 30m telescope. We present the first identification in space of the ketenyl radical (HCCO) toward the starless core Lupus-1A and the molecular cloud L483, and the detection of the related molecules ketene (HCCO) and acetaldehyde (CHCHO) in these two sources and 3 additional dark clouds. We also report the detection of the formyl radical (HCO) in the 9 targeted sources and of propylene (CHCHCH) in 4 of the observed sources, which extends significantly the number of dark clouds where these molecules are known to be present.

THE PECULIAR DISTRIBUTION OF CHCN IN IRC +10216 SEEN BY ALMA.

IRC +10216 is a circumstellar envelope around a carbon-rich evolved star which contains a large variety of molecules. According to interferometric observations, molecules are distributed either concentrated around the central star or as a hollow shell with a radius of ~15″. We present ALMA Cycle 0 band 6 observations of the = 14 - 13 rotational transition of CHCN in IRC +10216, obtained with an angular resolution of [Formula: see text].

SI-BEARING MOLECULES TOWARD IRC+10216: ALMA UNVEILS THE MOLECULAR ENVELOPE OF CWLEO.

We report the detection of SiS rotational lines in high-vibrational states as well as SiO and SiC lines in their ground vibrational state toward IRC+10216 during the Atacama Large Millimeter Array Cycle 0. The spatial distribution of these molecules shows compact emission for SiS and a more extended emission for SiO and SiC, and also proves the existence of an increase in the SiC emission at the outer shells of the circumstellar envelope. We analyze the excitation conditions of the vibrationally excited SiS using the population diagram technique, and we use a large velocity gradient model to compare with the observations.

Probing non polar interstellar molecules through their protonated form: Detection of protonated cyanogen (NCCNH).

Cyanogen (NCCN) is the simplest member of the series of dicyanopolyynes. It has been hypothesized that this family of molecules can be important constituents of interstellar and circumstellar media, although the lack of a permanent electric dipole moment prevents its detection through radioastronomical techniques. Here we present the first solid evidence of the presence of cyanogen in interstellar clouds through the detection of its protonated form toward the cold dark clouds TMC-1 and L483.

Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains.

We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the HIFI instrument on board and with the IRAM 30-m telescope. They cover several observing periods spreading over 3 years.

Warm water vapour in the sooty outflow from a luminous carbon star.

The detection of circumstellar water vapour around the ageing carbon star IRC +10216 challenged the current understanding of chemistry in old stars, because water was predicted to be almost absent in carbon-rich stars. Several explanations for the water were postulated, including the vaporization of icy bodies (comets or dwarf planets) in orbit around the star, grain surface reactions, and photochemistry in the outer circumstellar envelope. With a single water line detected so far from this one carbon-rich evolved star, it is difficult to discriminate between the different mechanisms proposed.

The essential signature of a massive starburst in a distant quasar.

Observations of carbon monoxide emission in high-redshift (zeta > 2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus powered by accretion of gas onto a supermassive black hole, and a key question is whether their extremely high infrared luminosities result from the active galactic nucleus, from bursts of massive star formation (associated with the molecular gas), or both. In the Milky Way, high-mass stars form in the dense cores of interstellar molecular clouds, where gas densities are n(H2) > 10(5) cm(-3) (refs 1, 2).

[Activity of W-sex heterochromatin and accumulation of the nuage in nurse cells of the lepidopteran Ephestia].

In the Lepidopteran Ephestia, in the female sex, the W chromosome, with which no function is known to be associated, is, in whole or part, maintained in a heterochromatic state in all cellular categories, except for the oocyte. In the present work, however, W-sex heterochromatin (W-SH) is demonstrated by ultrastructural autoradiography to be transcriptionally active in nurse cells during previtellogenesis. This activity is accompanied by accumulation of "nuage" in the perinuclear cytoplasm, both phenomena arresting at the beginning of vitellogenesis.

In situ hybridization: a routine method for parallel localization of DNA sequences and of their transcripts in consecutive paraffin sections with the use of 3H-labelled nick translated cloned DNA probes.

A routine in situ hybridization method is described and discussed, which allows parallel detection of repeated DNA sequences and of their abundant transcripts in consecutive tissue sections of a same biological sample with a unique probe. The protocol, based on the use of classical 3H-labelled nick translated cloned DNA probes and of conventional paraffin sections of ethanol-acetic acid-fixed tissues, consists of a simple combination of procedures in current use for separate detection of either RNA or DNA. Different treatments recommended in other methods are omitted or simplified, making the protocol suitable for routine use.