Browsing by Subject "stars: AGB and post-AGB"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Open Access
    Aperture synthesis imaging of the carbon AGB star R Sculptoris: Detection of a complex structure and a dominating spot on the stellar disk
    (2017) Wittkowski, M; Hofmann, K-H; Höfner, S; Le Bouquin, J B; Nowotny, W; Paladini, C; Young, J; Berger, J-P; Brunner, M; de Gregorio-Monsalvo, I; Eriksson, K; Hron, J; Humphreys, E M L; Lindqvist, M; Maercker, M; Mohamed, S; Olofsson, H; Ramstedt, S; Weigelt, G
    Aims. We present near-infrared interferometry of the carbon-rich asymptotic giant branch (AGB) star R Sculptoris (R Scl).
  • Thumbnail Image
    Item
    Open Access
    Near-infrared spectro-interferometry of Mira variables and comparisons to 1D dynamic model atmospheres and 3D convection simulations
    (2016) Wittkowski, M; Chiavassa, A; Freytag, B; Scholz, M; Höfner, S; Karovicova, I; Whitelock, P A
    Aims. We aim at comparing spectro-interferometric observations of Mira variable asymptotic giant branch (AGB) stars with the latest 1D dynamic model atmospheres based on self-excited pulsation models (CODEX models) and with 3D dynamic model atmospheres including pulsation and convection (CO5BOLD models) to better understand the processes that extend the molecular atmosphere to radii where dust can form.
  • Thumbnail Image
    Item
    Open Access
    The ALMA detection of CO rotational line emission in AGB stars in the Large Magellanic Cloud
    (2016) Groenewegen, M A T; Vlemmings, W H T; Marigo, P; Sloan, G C; Decin, L; Feast, M W; Goldman, S R; Justtanont, K; Kerschbaum, F; Matsuura, M; McDonald, I; Olofsson, H; Sahai, R; van Loon, J Th; Wood, P R; Zijlstra, A A; Bernard-Salas, J; Boyer, M L; Guzman-Ramirez, L; Jones, O C; Lagadec, E; Meixner, M; Rawlings, M G; Srinivasan, S
    Context. Low- and intermediate-mass stars lose most of their stellar mass at the end of their lives on the asymptotic giant branch (AGB). Determining gas and dust mass-loss rates (MLRs) is important in quantifying the contribution of evolved stars to the enrichment of the interstellar medium.
  • Thumbnail Image
    Item
    Open Access
    The Spitzer spectroscopic survey of S-type stars
    (2012) Smolders, K; Neyskens, P; Blommaert, J A D L; Hony, S; Van Winckel, H; Decin, L; Van Eck, S; Sloan, G C; Cami, J; Uttenthaler, S; Degroote, P; Barry, D; Feast, M; Groenewegen, M A T; Matsuura, M; Menzies, J; Sahai, R; van Loon, J Th; Zijlstra, A A; Acke, B; Bloemen, S; Cox, N; de Cat, P; Desmet, M; Exter, K; Ladjal, D; Østensen, R; Saesen, S; van Wyk, F; Verhoelst, T; Zima, W
    Context. S-type AGB stars are thought to be in the transitional phase between M-type and C-type AGB stars. Because the composition of the circumstellar environment reflects the photospheric abundances, one may expect a strong influence of the stellar C/O ratio on the molecular chemistry and the mineralogy of the circumstellar dust.