1,140 research outputs found
Calibrating damping rates with LEGACY linewidths
Linear damping rates of radial oscillation modes in selected stars
are estimated with the help of a nonadiabatic stability analysis. The
convective fluxes are obtained from a nonlocal, time-dependent convection
model. The mixing-length parameter is calibrated to the surface-convection-zone
depth of a stellar model obtained from fitting adiabatic frequencies to the
LEGACY observations, and two of the three nonlocal convection parameters are
calibrated to the corresponding LEGACY linewidth measurements. The atmospheric
structure in the 1D stability analysis adopts a temperature-optical-depth
relation derived from 3D hydrodynamical simulations. Results from 3D
simulations are also used to calibrate the turbulent pressure and to guide the
functional form of the depth-dependence of the anisotropy of the turbulent
velocity field in the 1D stability computations.Comment: 4 pages, 4 figures, refereed conference proceedings, "Seismology of
the Sun and the Distant Stars 2016", M\'ario J.P.F.G. Monteiro, Margarida S.
Cunha, Jo\~ao M.T. Ferreira (eds), EPJ Web of Conference
On the seismic age and heavy-element abundance of the Sun
We estimate the main-sequence age and heavy-element abundance of the Sun by
means of an asteroseismic calibration of theoretical solar models using only
low-degree acoustic modes from the BiSON. The method can therefore be applied
also to other solar-type stars, such as those observed by the NASA satellite
Kepler and the planned ground-based Danish-led SONG network. The age,
4.60+/-0.04 Gy, obtained with this new seismic method, is similar to, although
somewhat greater than, today's commonly adopted values, and the surface
heavy-element abundance by mass, Zs=0.0142+/-0.0005, lies between the values
quoted recently by Asplund et al. (2009) and by Caffau et al. (2009). We stress
that our best-fitting model is not a seismic model, but a theoretically evolved
model of the Sun constructed with `standard' physics and calibrated against
helioseismic data.Comment: 16 pages, 11 figures, 5 tables, accepted for publication in MNRA
When Heritage Preservation Meets Living Memory: Constructing the Medina of Fez as a World Heritage Heterotopia
This project engages the UNESCO World Heritage program\u27s international place-making and heritage preservation campaign, and the processes that are carried out to transform an everyday cultural place into a World Heritage site. I consider what effects these preservation projects and the tourists they attract have on communities of living memory, while also engaging non-Western conceptions of heritage and the local processes for how it is preserved or produced in such contexts. To these ends, I look at one of the first non-Western urban sites to be inscribed on the World Heritage list-- the Medina of Fez, Morocco. The Medina offers a rich site for this analysis given its complex history as a preservation project, its status as the cultural capital of Morocco, and for a number of other reasons. I ask how preservation practices and protocols, as well as various discourses together construct the Medina as a World Heritage city and through what means is this spatial dynamic sustained. I also examine the effects of this Western driven global place-making and heritage preservation campaign employed within a non-Western place of living memory and memory practices. Through engaging these questions, I offer both a top-down (text-based analysis) and a bottom-up analysis (embodied spatial analysis) that draws from Foucaultian spatial theory, Michel de Certeau\u27s poetics of space, and from literature in rhetorical studies and critical heritage studies. What follows is a three-part discussion of how the World Heritage place-making and preservation practices constitute a preservationist apparatus that renders heterotopic effects, how the heterotopia is grounded and sustained by the pedestrian rhetorics of tourists, local discourse, material preservation. Further, I engage how local meaning-making and memory work in the Medina of Fez offers a different understanding of how heritage is preserved and produced
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