On the reliability of mass-loss-rate estimates for AGB stars
- S. Ramstedt, F. Schoeier, H. Olofsson, A. Lundgren
- Physics
- 3 June 2008
Context. In the recent literature there has been some doubt as to the reliability of CO multi-transitional line observations as a mass-loss-rate estimator for AGB stars. Aims. Using new well-calibr…
The 12CO/13CO ratio in AGB stars of different chemical type - Connection to the 12C/13C ratio and the evolution along the AGB
- S. Ramstedt, H. Olofsson
- Physics
- 25 May 2014
Aims. The aim of this paper is to investigate the evolution of the C-12/C-13 ratio along the AGB through the circumstellar (CO)-C-12/(CO)-C-13 abundance ratio. This is the first time a sample…
The abundance of HCN in circumstellar envelopes of AGB stars of different chemical type
- F. Schoier, S. Ramstedt, H. Olofsson, M. Lindqvist, J. Bieging, K. Marvel
- Physics
- 10 January 2013
Aims. A multi-transition survey of HCN (sub-) millimeter line emission from a large sample of asymptotic giant branch (AGB) stars of different chemical type is presented. The data are analysed and…
Circumstellar water vapour in M-type AGB stars: radiative transfer models, abundances, and predictions for HIFI
- M. Maercker, F. Schoeier, H. Olofsson, P. Bergman, S. Ramstedt
- Physics, Geology
- 7 January 2008
Context. Surprisingly high amounts of H 2 O have recently been reported in the circumstellar envelope around the M-type asymptotic giant branch star W Hya. This has lead to the speculation that…
Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris
- M. Maercker, S. Mohamed, L. Nyman
- PhysicsNature
- 10 October 2012
It is concluded that R Sculptoris is a binary system that underwent a thermal pulse about 1,800 years ago, lasting approximately 200 years, and about three times more mass was returned to the interstellar medium during and immediately after the pulse than previously thought.
The wonderful complexity of the Mira AB system
- S. Ramstedt, S. Mohamed, S. Sacuto
- Physics, Geology
- 1 October 2014
We have mapped the (CO)-C-12(3-2) line emission around the Mira AB system at 0 ''.5 resolution using the Atacama Large Millimeter/submillimeter Array (ALMA). The CO map shows amazing complexity. The…
Circumstellar molecular line emission from S-type AGB stars: Mass-loss rates and SiO abundances
- S. Ramstedt, F. Schoeier, H. Olofsson
- Physics
- 10 March 2009
Aims: The main aim is to derive reliable mass-loss rates and circumstellar SiO abundances for a sample of 40 S-type AGB stars based on new multi-transitional CO and SiO radio line observations. In…
The Herschel Planetary Nebula Survey (HerPlaNS) - I. Data overview and analysis demonstration with NGC 6781
- T. Ueta, D. Ladjal, I. Yamamura
- Physics
- 11 March 2014
Context. This is the first of a series of investigations into far-IR characteristics of 11 planetary nebulae (PNe) under the Herschel Space Observatory open time 1 program, Herschel Planetary Nebula…
Resolving the stellar activity of the Mira AB binary with ALMA
- W. Vlemmings, S. Ramstedt, M. Karovska
- Physics
- 26 March 2015
Aims. We present the size, shape, and flux densities at millimeter continuum wavelengths, based on ALMA science verification observations in Band 3 (similar to 94.6 GHz) and Band 6 (similar to 228.7…
Mass-loss properties of S-stars on the AGB
- S. Ramstedt, F. Schoeier, H. Olofsson, A. Lundgren
- Physics
- 26 May 2006
We have used a detailed non-LTE radiative transfer code to model new APEX CO(J = 3 → 2) data, and existing CO radio line data, on a sample of 40 AGB S-stars. The derived mass-loss-rate distribution…
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