AKARI Mission Program: Excavating Mass Loss History in Extended Dust Shells of Evolved Stars (MLHES) I. Far-IR Photometry

Abstract

We performed a far-IR imaging survey of the circumstellar dust shells of 144 evolved stars as a mission programme of the AKARI infrared astronomical satellite using the Far-Infrared Surveyor (FIS) instrument. With this survey, we deliver far-IR surface brightness distributions of roughly 10' x 40' or 10' x 20' areas of the sky around the target evolved stars in the four FIS bands at 65, 90, 140, and 160 microns. Our objectives are to characterize the far-IR surface brightness distributions of the cold dust component in the circumstellar dust shells, from which we derive the amount of cold dust grains as low as 20 K and empirically establish the history of the early mass loss history. In this first installment of the series, we introduce the project and its aims, describe the observations, data reduction, and surface brightness correction process, and present the entire data set along with the results of integrated photometry measurements (i.e., the central source and circumstellar dust shell altogether). We find that (1) far-IR emission is detected from all but one object at the spatial resolution about 30" - 50" in the corresponding bands, (2) roughly 60 - 70 % of the target sources show some extension, (3) previously unresolved nearby objects in the far-IR are now resolved around 28 target sources, (4) the results of photometry measurements are reasonable with respect to the entries in the AKARI/FIS Bright Source Catalogue, despite the fact that the targets are assumed to be point-sources when catalogue flux densities were computed, and (5) an IR two-color diagram would place the target sources in a roughly linear distribution that may correlate with the age of the circumstellar dust shell and can potentially be used to identify which targets are more extended than others.

To be published in PASJ AKARI Special Issue: 25 pages, 5 figures, 5 tables (and 28 supplementary figures available only in PASJ on-line)

References in corpus (14)

• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants
• Unexpectedly large mass loss during the thermal pulse cycle of the red giant R Sculptoris!
• Preplanetary Nebulae: An HST Imaging Survey and a New Morphological Classification System
• An evolutionary catalogue of Galactic post-AGB and related objects
• The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel. I. Evidence of clumps, multiple arcs, and a linear bar-like structure
• The $AKARI$ Far-Infrared All-Sky Survey Maps
• Large-scale environments of binary AGB stars probed by Herschel - I. Morphology statistics and case studies of R Aquarii and W Aquilae
• Calibration of the AKARI Far-infrared All Sky Survey Maps
• The Herschel Planetary Nebula Survey (HerPlaNS) I. Data Overview and Analysis Demonstration with NGC 6781
• The Herschel Planetary Nebula Survey (HerPlaNS) - a comprehensive dusty photoionization model of NGC6781
• A Spitzer Study of the Mass Loss Histories of Three Bipolar Pre-Planetary Nebulae
• Surface Brightness Correction for Compact Extended Sources Observed by the AKARI Far-Infrared Surveyor (FIS) in the Slow-Scan Mode
• On Surface Brightness and Flux Calibration for Point and Compact Extended Sources in the AKARI Far-IR All-Sky Survey (AFASS) Maps

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