ORBi: Miglio Andrea - Evidence for a sharp structure variation inside a red-giant star

Reference : Evidence for a sharp structure variation inside a red-giant star


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
	To cite this reference:	http://hdl.handle.net/2268/77865

Title :	Evidence for a sharp structure variation inside a red-giant star
Language :	English
Author, co-author :	Miglio, Andrea [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie]
	Montalban Iglesias, Josefa [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie >]
	Carrier, F. [Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium]
	De Ridder, J. [Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium]
	Mosser, B. [LESIA, UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon, France]
	Eggenberger, P. [Observatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland]
	Scuflaire, Richard [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Evol. et stabilité des étoiles et des amas d'étoiles (ESEA) >]
	Ventura, P. [INAF - Osservatorio di Roma, via Frascati, 33 Monteporzio Catone, RM, Italy]
	D'Antona, F. [INAF - Osservatorio di Roma, via Frascati, 33 Monteporzio Catone, RM, Italy]
	Noels-Grötsch, Arlette [Institut d'Astrophysique et de Géophysique de l'Université de Liège, 17Allée du 6 Août, 4000 Liège, Belgium) AK(LESIA, UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon,France]
	Baglin, A. [LESIA, UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon, France)]
Publication date :	1-Sep-2010
Journal title :	Astronomy and Astrophysics
Publisher :	EDP Sciences
Volume :	520
Pages :	L6
Peer reviewed :	Yes (verified by ORBi)
Audience :	International
ISSN :	0004-6361
e-ISSN :	1432-0746
City :	Les Ulis
Country :	France
Keywords :	[en] asteroseismology ; stars: interiors ; stars: oscillations ; stars: fundamental parameters ; stars: individual: HR 7349
Abstract :	[en] Context. The availability of precisely determined frequencies of radial and non-radial oscillation modes in red giants is finally paving the way for detailed studies of the internal structure of these stars. <BR /> Aims: We look for the seismic signature of regions of sharp structure variation in the internal structure of the CoRoT target HR 7349. <BR /> Methods: We analyse the frequency dependence of the large frequency separation and second frequency differences, as well as the behaviour of the large frequency separation obtained with the envelope auto-correlation function. <BR /> Results: We find evidence for a periodic component in the oscillation frequencies, i.e. the seismic signature of a sharp structure variation in HR 7349. In a comparison with stellar models we interpret this feature as caused by a local depression of the sound speed that occurs in the helium second-ionization region. Using solely seismic constraints this allows us to estimate the mass (M = 1.2[SUB]-0.4[/SUB][SUP]+0.6[/SUP] M_&sun;) and radius (R = 12.2[SUB]-1.8[/SUB][SUP]+2.1[/SUP] R_&sun;) of HR 7349, which agrees with the location of the star in an HR diagram.
Permalink :	http://hdl.handle.net/2268/77865
	also: http://hdl.handle.net/2268/130370
DOI :	10.1051/0004-6361/201015442
Other URL :	http://adsabs.harvard.edu/abs/2010A%26A...520L...6M
	http://de.arxiv.org/abs/1009.1024

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