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

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 results that cover the past 817 days of an on-going monitoring project for 1.1\,mm lines in the archetypal carbon star IRC\,+10216, using both the compact 7-m array (ACA) of the Atacama Large Millimeter Array (ALMA) and an infrared telescope in tandem. The high sensitivity of the cumulative spectra across $\sim8$\,GHz frequency range has allowed us to detect about 164 known transitions of 21 molecules together with their isotopologues and about 80 unidentified lines and their variabilities. While only a handful of lines are found to be stable in time, most other lines are varying either in phase with or in anti-phase against near infrared light. The line profile shapes and variation phases of some lines are different from the single dish results, perhaps due to different angular resolutions.