2010
DOI: 10.1051/0004-6361/201015455
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Modelling chromospheric line profiles as diagnostics of velocity fields inω Centauri red giant stars

Abstract: Context. Mass loss of ∼0.1−0.3 M from Population II red giant stars (RGB) is a requirement of stellar evolution theory in order to account for several observational evidences in globular clusters. Aims. The aim of this study is to detect the presence of outward velocity fields, which are indicative of mass outflow, in six luminous red giant stars of the stellar cluster ω Cen. Methods. We compare synthetic line profiles computed using relevant model chromospheres to observed profiles of the Hα and Ca II K lines… Show more

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Cited by 17 publications
(15 citation statements)
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“…It is towards the higher end of the observed range of mass‐loss rates estimated from chromospheric line profiles (e.g. Dupree et al 2009; Vieytes et al 2011), suggesting that stronger mass‐loss at the RGB tip is important.…”
Section: Discussionmentioning
confidence: 93%
“…It is towards the higher end of the observed range of mass‐loss rates estimated from chromospheric line profiles (e.g. Dupree et al 2009; Vieytes et al 2011), suggesting that stronger mass‐loss at the RGB tip is important.…”
Section: Discussionmentioning
confidence: 93%
“…However, a varying metallicity should also change other properties of the convection-including the effective mixing length α parameter-thus possibly making this effect more important. To continue testing and refining these models, it is also important to utilize the newest and most accurate measurements of stellar mass loss rates (see, e.g., Schröder & Cuntz 2007;Willson 2009;Catelan 2009;Mauron & Josselin 2011;Vieytes et al 2011) and magnetic fields (Donati & Landstreet 2009;Vlemmings et al 2011). Finally, we emphasize that a complete description of latetype stellar winds requires the incorporation of other physical processes besides Alfvén waves and turbulence.…”
Section: Discussionmentioning
confidence: 99%
“…such low-metallicity, dust-producing giants, inferences from chromospheric line modelling (e.g. Judge & Stencel 1991;Vieytes et al 2010) appears to show that wind velocities do not decrease substantially from ∼10 km s −1 in the stages shortly prior to dust formation. We point out, however, that the highest mass-loss rates (and by inference the highest wind velocities) may be ruled out on evolutionary grounds ( §3.5).…”
Section: Error In the Mass-loss Ratementioning
confidence: 98%