ALMA monitoring of mm line variation in IRC+10216: I. Overview of millimeter variability

Abstract

Temporal variation of millimeter lines is a new direction of research for evolved stars. It has the potential to probe the dynamical wind launching processes from time dimension. We report here the first ALMA (Atacama Large Millimeter Array) results that cover 817 days of an on-going monitoring of 1.1 mm lines in the archetypal carbon star IRC +10216. The monitoring is done with the compact 7-m array (ACA) and in infrared with a 1.25 m telescope in Crimea. A high sensitivity of the cumulative spectra covering a total of ~7.2 GHz between 250 - 270 GHz range has allowed us to detect about 148 known transitions of 20 molecules, together with more of their isotopologues, and 81 unidentified lines. An overview of the variabilities of all detected line features are presented in spectral plots. Although a handful of lines are found to be very possibly stable in time, most other lines are varying either roughly in phase or in anti-correlation with the near-infrared light. Several lines have their variations in the ALMA data coincident with existing single dish monitoring results, while several others do not, which requires an yet unknown mechanism in the circumstellar envelop to explain.

arXiv comment26 pages, 4 figures, 2 tables, accepted by ApJ

References in corpus (13)

• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• ALMA data suggest the presence of a spiral structure in the inner wind of CW Leo
• An Interferometric Spectral-line Survey of IRC+10216 in the 345 GHz Band
• Clumpy dust clouds and extended atmosphere of the AGB star W Hya revealed with VLT/SPHERE-ZIMPOL and VLTI/AMBER
• Unveiling the dust nucleation zone of IRC+10216 with ALMA
• The size, luminosity and motion of the extreme carbon star IRC+10216 (CW Leonis)
• Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains
• Clumpy dust clouds and extended atmosphere of the AGB star W Hya revealed with VLT/SPHERE-ZIMPOL and VLTI/AMBER II. Time variations between pre-maximum and minimum light
• The wind of the M-type AGB star RT Virginis probed by VLTI/MIDI
• Monitor variability of millimeter lines in IRC +10216
• The maser emitting structure and time variability of the SiS lines J=14-13 and 15-14 in IRC+10216
• Vibrationally Excited C${}_4$H
• Spatially resolving the atmosphere of the non-Mira-type AGB star SW Vir in near-infrared molecular and atomic lines with VLTI/AMBER

Cited by in corpus (6)

• On the accuracy of the ALMA flux calibration in the time domain and across spectral windows
• Investigating Anomalous Photochemistry in the Inner Wind of IRC+10216 Through Interferometric Observations of HC${}_3$N
• Charting Circumstellar Chemistry of Carbon-rich AGB Stars: I. ALMA 3 mm spectral surveys
• Infrared color separation between thin-shelled oxygen-rich and carbon-rich AGB stars
• Vibrationally excited HCN transitions in circumstellar envelopes of carbon-rich AGB stars
• New submillimetre HCN lasers in carbon-rich evolved stars