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We analyse new ALMA observations of the $^{29}$SiO ($\nu$=0, $J$=8$-$7) and SO$_2$($\nu$=0, $34_{3,31}$$-$$34_{2,32}$) line emissions of the circumstellar envelope (CSE) of the oxygen-rich AGB star R Dor. With a spatial resolution of…

Solar and Stellar Astrophysics · Physics 2021-05-12 P. T. Nhung , D. T. Hoai , P. Tuan-Anh , P. Darriulat , P. N. Diep , N. B. Ngoc , N. T. Phuong , T. T. Thai

ALMA observations of CO(1-0) and CO(2-1) emissions of the circumstellar envelope of EP Aqr, an oxygen-rich AGB star, are reported. A thorough analysis of their properties is presented using an original method based on the separation of the…

Solar and Stellar Astrophysics · Physics 2019-01-16 D. T. Hoai , P. T. Nhung , P. Tuan-Anh , P. Darriulat , P. N. Diep , T. Le Bertre , N. T. Phuong , T. T. Thai , J. M. Winters

The mass loss experienced on the asymptotic giant branch (AGB) at the end of the lives of low- and intermediate-mass stars is widely accepted to rely on radiation pressure acting on dust grains formed in the extended AGB atmospheres. The…

Solar and Stellar Astrophysics · Physics 2024-02-22 T. Khouri , H. Olofsson , W. H. T. Vlemmings , T. Schirmer , D. Tafoya , M. Maercker , E. De Beck , L. -Å. Nyman , M. Saberi

The circumstellar environment of the AGB star L$_{\rm 2}$ Puppis was observed with ALMA in cycle 3, with a resolution of $15 \times 18 \rm\ mas$. The molecular emission shows a differentially rotating disk, inclined to a nearly edge-on…

Solar and Stellar Astrophysics · Physics 2018-03-15 Ward Homan , Anita Richards , Leen Decin , Pierre Kervella , Alex de Koter , Iain McDonald , Keiichi Ohnaka

Gaseous outflows are key phenomena in the evolution of galaxies, as they affect star formation (either positively or negatively), eject gas from the core or disk, and directly cause mixing of pristine and processed material. Active outflows…

Astrophysics of Galaxies · Physics 2022-11-23 G. C. Jones , R. Maiolino , C. Circosta , J. Scholtz , S. Carniani , Y. Fudamoto

Stars on the asymptotic giant branch (AGB) lose substantial amounts of matter, to the extent that they are important for the chemical evolution of, and dust production in, the universe. The mass loss is believed to increase gradually with…

Solar and Stellar Astrophysics · Physics 2015-10-28 Hans Olofsson , Per Bergman , Michael Lindqvist

We analyse continuum and molecular emission, observed with ALMA, from the dust-enshrouded intermediate-mass AGB star OH 30.1 -0.7. We find a secondary peak in the continuum maps, "feature B", separated by 4.6" from the AGB star, which…

Low- and intermediate-mass stars evolve through the asymptotic giant branch (AGB), when an efficient mass-loss process removes a significant fraction of their initial mass. A substantial increase in the mass-loss rate at the end of the AGB…

Stars with masses between roughly 1 and 8~$M_\odot$ end their lives on the asymptotic giant branch (AGB), when intense mass loss takes place. The outflows are generally accepted to be driven by radiation pressure acting on dust grains that…

High angular resolution Australia Telescope Compact Array (ATCA) observations of SiO `thermal' millimetre line emission towards the two oxygen-rich, low mass loss rate AGB stars R Dor and L2 Pup are presented. In both cases the emission is…

Astrophysics · Physics 2009-11-10 F. L. Schoeier , H. Olofsson , T. Wong , M. Lindqvist , F. Kerschbaum

We analyse ALMA observations of the SO($J_K=6_5-5_4$) emission of the circumstellar envelope of oxygen-rich AGB star R Dor, probing distances between 20 and 100 au from the star where the nascent wind is building up. We give evidence for…

Solar and Stellar Astrophysics · Physics 2019-10-02 P. T. Nhung , D. T. Hoai , P. Tuan-Anh , P. Darriulat , P. N. Diep , N. T. Phuong , T. T. Thai

We present observations and analysis of the massive molecular outflow G331.512-0.103, obtained with ALMA band 7, continuing the work from Merello et al. (2013). Several lines were identified in the observed bandwidth, consisting of two…

Context: For stars with initial masses below about 1 solar mass, the mass loss during the first red giant branch (RGB) phase dominates mass loss in the later asymptotic giant branch (AGB) phase. Nevertheless, mass loss on the RGB is still…

Solar and Stellar Astrophysics · Physics 2015-06-18 M. A. T. Groenewegen

Single dish observations of AGB star L$_2$ Pup have revealed exceptionally low mass loss rate and expansion velocity, challenging interpretations in terms of standard wind models. Recent VLT and ALMA observations have drawn a detailed…

Solar and Stellar Astrophysics · Physics 2021-12-15 D. T. Hoai , P. T. Nhung , P. Darriulat , P. N. Diep , N. B. Ngoc , T. T. Thai , P. Tuan-Anh

ALMA observations of the Galactic center with spatial resolution $2.61"\times0.97"$ resulted in the detection of 11 SiO (5-4) clumps of molecular gas within 0.6pc (15$"$) of Sgr A*, interior to the 2-pc circumnuclear molecular ring. The…

Astrophysics of Galaxies · Physics 2015-06-15 F. Yusef-Zadeh , M. Royster , M. Wardle , R. Arendt , H. Bushouse , D. C. Lis , M. W. Pound , D. A. Roberts , B. Whitney , A. Wootten

We study the morpho-kinematics of the circumbinary envelope of Mira Ceti between $\sim$100 and $\sim$350 au from the stars using ALMA observations of the SiO ($\nu$=0, $J$=5-4) and CO ($\nu$=0, $J$=3-2) emissions with the aim of presenting…

Solar and Stellar Astrophysics · Physics 2020-05-13 D. T. Hoai , P. Tuan-Anh , P. T. Nhung , P. Darriulat , P. N. Diep , N. T. Phuong , T. T. Thai

Silicon monoxide (SiO) traces the physical conditions and dynamics in the circumstellar envelopes (CSEs) of AGB stars. We present high-resolution ALMA Band 6 observations of highly excited SiO emission in 14 oxygen-rich AGB stars. We cover…

We analyse archival ALMA (Atacama Large Millimeter/submillimeter Array) observations of two molecular line emissions, $^{12}$CO(3-2) and $^{29}$SiO(8-7), from oxygen-rich AGB (Asymptotic Giant Branch) star W Hya. Together with results of…

Solar and Stellar Astrophysics · Physics 2022-11-07 Do Thi Hoai , Pham Tuyet Nhung , Pierre Darriulat , Pham Ngoc Diep , Nguyen Bich Ngoc , Tran Thi Thai , Pham Tuan-Anh

The S-type asymptotic giant branch (AGB) star $\pi^{1}$ Gruis has a known companion at a separation of $\approx$400 AU. The envelope structure, including an equatorial torus and a fast bipolar outflow, is rarely seen in the AGB phase and is…

Solar and Stellar Astrophysics · Physics 2017-09-28 L. Doan , S. Ramstedt , W. H. T. Vlemmings , S. Höfner , E. De Beck , F. Kerschbaum , M. Lindqvist , M. Maercker , S. Mohamed , C. Paladini , M. Wittkowski

A spectral scan of the circumstellar environment of the asymptotic giant branch (AGB) star R~Doradus was taken with ALMA in cycle 2 at frequencies between 335 and 362 GHz and with a spatial resolution of $\sim$150 milliarcseconds. Many…

Solar and Stellar Astrophysics · Physics 2018-06-27 Ward Homan , Taissa Danilovich , Leen Decin , Alex de Koter , Joseph Nuth , Marie Van de Sande
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