ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA
S. H. J. Wallstrom, T. Danilovich, H. S. P. Muller, C. A. Gottlieb, S. Maes, M. Van de Sande, L. Decin, A. M. S. Richards, A. Baudry, J. Bolte, T. Ceulemans, F.… 展开作者
S. H. J. Wallstrom, T. Danilovich, H. S. P. Muller, C. A. Gottlieb, S. Maes, M. Van de Sande, L. Decin, A. M. S. Richards, A. Baudry, J. Bolte, T. Ceulemans, F. De Ceuster, A. de Koter, I. El Mellah, M. Esseldeurs, S. Etoka, D. Gobrecht, E. Gottlieb, M. Gray, F. Herpin, M. Jeste, D. Kee, P. Kervella, T. Khouri, E. Lagadec, J. Malfait, L. Marinho, I. McDonald, K. M. Menten, T. J. Millar, M. Montarges, J. A. Nuth, J. M. C. Plane, R. Sahai, L. B. F. M. Waters, K. T. Wong, J. Yates, A. Zijlstra
备注：
19 pages plus appendices, forthcoming publication in Astronomy & Astrophysics
冷演化恒星的尘埃风是新合成物质的重要贡献者，这些物质丰富了银河系以及未来世代的恒星。然而，尘埃形成和风启动背后的物理与化学细节尚未被精确确定。近期空间分辨观测表明，获得更全面的星周化学视角十分重要，但由于频率和角分辨率等观测细节很少具有可比性，对化学与物理之间复杂相互作用的比较研究仍然困难。为了克服这些不足，ATOMIUM是一项ALMA大型项目，旨在以均匀的观测条件，在约0.02角秒至1.4角秒之间的三种角分辨率下，研究一组多样化的富氧演化恒星星周包层的物理和化学。本文总结了这些源的分子清单，以及恒星参数与分子含量之间的相关性。我们使用ALMA Band 6在多个调谐设置下观测了17颗富氧或S型渐近巨星支（AGB）恒星和红超巨星（RSG），目标是一系列分子，以探测星周包层，尤其是靠近恒星的尘埃形成化学。我们系统地确定了谱线的分子载体，并根据积分强度图测量了它们的光谱参数以及每条谱线发射的角向范围。在整个ATOMIUM样本中，我们探测到24种不同分子及其同位素体的291条跃迁。其中包括在富氧AGB/RSG恒星中的若干首次探测：PO v=1、SO2 v1=1和v2=2，以及若干高能H2O跃迁。我们还在S型AGB恒星中发现若干首次探测：振动激发HCN v2=2,3和SiS v=4,5,6，以及在W Aql中首次探测到分子SiC、AlCl和AlF。
英文摘要：
The dusty winds of cool evolved stars are a major contributor of the newly synthesised material enriching the Galaxy and future generations of stars. However, the details of the physics and chemistry behind dust formation and wind launching have yet to be pinpointed. Recent spatially resolved observations show the importance of gaining a more comprehensive view of the circumstellar chemistry, but a comparative study of the intricate interplay between chemistry and physics is still difficult because observational details such as frequencies and angular resolutions are rarely comparable. Aiming to overcome these deficiencies, ATOMIUM is an ALMA Large Programme to study the physics and chemistry of the circumstellar envelopes of a diverse set of oxygen-rich evolved stars under homogeneous observing conditions at three angular resolutions between ~0.02"-1.4". Here we summarize the molecular inventory of these sources, and the correlations between stellar parameters and molecular content. Seventeen oxygen-rich or S-type asymptotic giant branch (AGB) and red supergiant (RSG) stars have been observed in several tunings with ALMA Band 6, targeting a range of molecules to probe the circumstellar envelope and especially the chemistry of dust formation close to the star. We systematically assigned the molecular carriers of the spectral lines and measured their spectroscopic parameters and the angular extent of the emission of each line from integrated intensity maps. Across the ATOMIUM sample, we detect 291 transitions of 24 different molecules and their isotopologues. This includes several first detections in oxygen-rich AGB/RSG stars: PO v=1, SO2 v1=1 and v2=2, and several high energy H2O transitions. We also find several first detections in S-type AGB stars: vibrationally excited HCN v2=2,3 and SiS v=4,5,6, as well as first detections of the molecules SiC, AlCl, and AlF in W Aql...
This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter-submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify chemical processes applicable to other astrophysical environments. 17 oxygen-rich AGB and RSG stars spanning a range in (circum)stellar parameters and evolutionary phases were observed in a homogeneous observing strategy allowing for an unambiguous compa…
Aims. Through the ATOMIUM project, based on an ALMA large program, we aim to present a consistent view of a sample of 17 nearby cool evolved stars (Aymptotic Giant Branch and red supergiant stars). Methods. Here we present VLT/SPHERE-ZIMPOL polarimetric maps obtained in the visible of 14 out of the 17 ATOMIUM sources. They were obtained contemporaneously with the ALMA high spatial resolution data. To help interpret the polarized signal, we produced synthetic maps of light scattering by dust, through 3D radiative transfer simulations with the RADMC3D code. Results. The degree of linear polariza…
S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate, but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star, W Aql. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results. We analyse ALMA obs…
Complex organic molecules (COM) are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these COM form remains an open question. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar binary IRAS 16293-2422 (IRAS16293). We utilised observations from the ALMA Protostellar Interferometric Line Survey of IRAS16293. The species identification and the rotational temperature and column density estimation were derived by fitting the extracted spectr…
Evolved low- to intermediate-mass stars are known to shed their gaseous envelope into a large, dusty, molecule-rich circumstellar nebula which typically develops a high degree of structural complexity. Most of the large-scale, spatially correlated structures in the nebula are thought to originate from the interaction of the stellar wind with a companion. As part of the Atomium large programme, we observed the M-type asymptotic giant branch (AGB) star R Hydrae with ALMA. The morphology of the inner wind of R Hya, which has a known companion at ~3500 au, was determined from maps of CO and SiO ob…
ATOMIUM: Inner circumstellar envelopes of oxygen-rich AGB stars as revealed by highly excited SiO lines
National Astronomical Research Institute of Thailand (Public Organization)（泰国国家天文研究所）；Jodrell Bank Centre for Astrophysics, The University of Manchester（曼彻斯特大学乔德雷尔银行天体物理学中心）；Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS（波尔多大学CNRS波尔多天体物理实验室）；School of Physics & Astronomy, Monash University（蒙纳士大学物理与天文学院）；Institute of Astronomy, KU Leuven（荷鲁汶大学天文研究所）；School of Chemistry, University of Leeds（利兹大学化学学院）；Leiden Observatory, Leiden University（莱顿大学莱登天文台）；Departament de Física, EEBE, Universitat Politècnica de Catalunya（加泰罗尼亚理工大学EEBE物理系）；Harvard-Smithsonian Center for Astrophysics（哈佛-史密森尼天体物理中心）；Universität zu Köln, Astrophysik/I. Physikalisches Institut（科隆大学天体物理/第一物理研究所）；California Institute of Technology, Jet Propulsion Laboratory（加州理工学院喷气推进实验室）；Theoretical Astrophysics, Department of Physics and Astronomy, Uppsala University（乌普萨拉大学物理与天文学院理论天体物理）；Department of Computer Science, University College London（伦敦大学学院计算机科学系）
通过高分辨率 ALMA 观测，研究氧丰富晚生星的内 circumstellar 包层，发现高激发 SiO 线的分布特征及与质量损失的关系。
The chemical composition of high-mass protostars reflects the physical evolution associated with different stages of star formation. In this study, the molecular inventory of the forming high-mass star AFGL 4176 is studied in detail at high angular resolution (~0.35 arcsec) using ALMA. This high resolution makes it possible to separate the emission associated with the inner hot envelope and disk around the forming star from that of its cool outer envelope. In addition, the high sensitivity of ALMA makes it possible to identify weak and optically thin lines and allows for many isotopologues to …
We report the first molecular line survey of Supernova 1987A in the millimetre wavelength range. In the ALMA 210--300 and 340--360 GHz spectra, we detected cold (20--170 K) CO, 28SiO, HCO+ and SO, with weaker lines of 29SiO from ejecta. This is the first identification of HCO+ and SO in a young supernova remnant. We find a dip in the J=6--5 and 5--4 SiO line profiles, suggesting that the ejecta morphology is likely elongated. The difference of the CO and SiO line profiles is consistent with hydrodynamic simulations, which show that Rayleigh-Taylor instabilities cause mixing of gas, with heavie…
Methyl isocyanate (CH$_{3}$NCO) and glycolonitrile (HOCH$_{2}$CN) are isomers and prebiotic molecules that are involved in the formation of peptide structures and the nucleobase adenine, respectively. ALMA observations of the intermediate-mass Class 0 protostar Serpens SMM1-a and ALMA-PILS data of the low-mass Class 0 protostar IRAS~16293B are used. Spectra are analysed with the CASSIS line analysis software package in order to identify and characterise molecules. CH$_{3}$NCO, HOCH$_{2}$CN, and various other molecules are detected towards SMM1-a. HOCH$_{2}$CN is identified in the PILS data tow…
This work aims to constrain the abundances of interstellar amides, by searching for this group of prebiotic molecules in the intermediate-mass protostar Serpens SMM1-a. ALMA observations are conducted toward Serpens SMM1. A spectrum is extracted toward the SMM1-a position and analyzed with the CASSIS line analysis software for the presence of characteristic rotational lines of a number of amides and other molecules. NH$_{2}$CHO, NH$_{2}$CHO $ν_{12}$=1, NH$_{2}^{13}$CHO, CH$_{3}$C(O)NH$_{2}$ $ν$=0,1, CH$_{2}$DOH, CH$_{3}$CHO, and CH$_{3}$C(O)CH$_{3}$ are securely detected, while trans-NHDCHO, N…
As host to two accreting planets, PDS 70 provides a unique opportunity to probe the chemical complexity of atmosphere-forming material. We present ALMA Band 6 observations of the PDS~70 disk and report the first chemical inventory of the system. With a spatial resolution of 0.4''-0.5'' ($\sim$50 au), 12 species are detected, including CO isotopologues and formaldehyde, small hydrocarbons, HCN and HCO+ isotopologues, and S-bearing molecules. SO and CH3OH are not detected. All lines show a large cavity at the center of the disk, indicative of the deep gap carved by the massive planets. The radia…
Complex organic molecules (COMs) are thought to form on icy dust grains in the earliest phase of star formation. The evolution of these COMs from the youngest Class 0/I protostellar phases toward the more evolved Class II phase is still not fully understood. Since planet formation seems to start early, and mature disks are too cold for characteristic COM emission lines, studying the inventory of COMs on solar system scales in the Class 0/I stage is relevant. ALMA Band 3 (3 mm) and Band 6 (1 mm) observations are obtained of seven Class 0 protostars in the Perseus and Serpens star-forming region…
