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Asteroseismology of cool stars: testing scaling laws and detecting signatures of rapid structure variation

Rodrigues Coelho, Hugo (2017)
Ph.D. thesis, University of Birmingham.

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Abstract

First, we investigated the ν max scaling relation, a widely-used equation that states that the frequency of maximum amplitude in a power spectrum scales with a combination of surface gravity and effective temperature. We tested how well the oscillations of cool main-sequence and sub-giant stars follow this relation, using a ensemble of asteroseismic targets observed by Kepler.

We then tested seismic scaling relations in a small group of 10 bright red-giant stars observed by Kepler. These giants, some of the brightest observed in the Kepler field, have precise values of parallaxes. We compared the measured distances with inferences made using asteroseismic parameters. We also combined high-quality spectroscopic data with seismic constraints to determine their evolutionary phase. We compared the observed surface abundances of lithium and carbon with models that account for additional mixing processes in redgiants.

Finally, we analyzed a group of 13 stars observed by Kepler, and use asteroseismic tools to extract modelindependent information about their internal regions. Our objective is to detect the so-called acoustic glitches, characterized as departures from the uniform frequency spacings predicted by the asymptotic relation. Such departures originate in regions where there is an abrupt change in the stratification of the star.

Type of Work:Ph.D. thesis.
Supervisor(s):Miglio, Andrea and Chaplin, William J.
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Physics and Astronomy
Additional Information:

Publications arising from thesis:

A test of the asteroseismic vmax scaling relation for solar-like oscillations in main-sequence
and subgiant stars. Coelho, H. R.; Chaplin, W. J.; Basu, S.; Serenelli, A.; Miglio, A. and
Reese, D. R., Monthly Notices of the Royal Astronomical Society, Volume 451, Issue 3,
p.3011-3020
http://dx.doi.org/10.1093/mnras/stv1175

Asteroseismology of Solar-Type Stars with K2: Detection of Oscillations in C1 Data.
Chaplin, W. J.; Lund, M. N.; Handberg, R.; Basu, S.; Buchhave, L. A.; Campante, T.
L.; Davies, G. R.; Huber, D.; Latham, D. W.; Latham, C. A.; Serenelli, A.; Antia, H.
M.; Appourchaux, T.; Ball, W. H.; Benomar, O.; Casagrande, L.; Christensen-Dalsgaard,
J.; Coelho, H. R.; Creevey, O. L.; Elsworth, Y.; García, R. A.; Gaulme, P.; Hekker, S.;
Kallinger, T.; Karo�, C.; Kawaler, S. D.; Kjeldsen, H.; Lundkvist, M. S.; Marcadon, F.;
Mathur, S.; Miglio, A.; Mosser, B.; Régulo, C.; Roxburgh, I.W.; Silva Aguirre, V.; Stello,
D.; Verma, K.; White, T. R.; Bedding, T. R.; Barclay, T.; Buzasi, D. L.; Dehuevels, S.;
Gizon, L.; Houdek, G.; Howell, S. B.; Salabert, D. and Soderblom, D. R., Publications of
the Astronomical Society of Pacific, Volume 127, Issue 956, pp. 1038-1044 (2015)
http://dx.doi.org/10.1086/683103

SpaceInn hare-and-hounds exercise: Estimation of stellar properties using space-based
asteroseismic data. Reese, D. R.; Chaplin, W. J.; Davies, G. R.; Miglio, A.; Antia, H. M.;
Ball,W. H.; Basu, S.; Buldgen, G.; Christensen-Dalsgaard, J.; Coelho, H. R.; Hekker, S.;
Houdek, G.; Lebreton, Y.; Mazumdar, A.; Metcalfe, T. S.; Silva Aguirre, V.; Stello, D.;
Verma, K., Astronomy & Astrophysics, Volume 592, id.A14, 27 pp.
http://dx.doi.org/10.1051/0004-6361/201527987

Subjects:QB Astronomy
QC Physics
Institution:University of Birmingham
ID Code:7405
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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