ATTENZIONE! IL REPOSITORY E’ APERTO ESCLUSIVAMENTE ALL’IMMISSIONE DEI RAPPORTI TECNICI (COLLEZIONE 4.01). NON E’ POSSIBILE INSERIRE PRODOTTI IN TUTTE LE ALTRE COLLEZIONI, A CAUSA DI PROBLEMI TECNICI. THE REPOSITORY IS OPEN EXCLUSIVELY FOR THE SUBMISSION OF TECHNICAL REPORTS (COLLECTION 4.01). SUBMISSIONS TO ALL OTHER COLLECTIONS ARE TEMPORARILY UNAVAILABLE, DUE TO TECHNICAL ISSUES.
 

Testing the asymptotic relation for period spacings from mixed modes of red giants observed with the Kepler mission

Journal
Date Issued
2016
Author(s)
Buysschaert, B.
•
Beck, P. G.
•
•
Christensen-Dalsgaard, J.
•
Aerts, C.
•
Arentoft, T.
•
Kjeldsen, H.
•
García, R. A.
•
Silva Aguirre, V.
•
Degroote, P.
DOI
Abstract
Context. Dipole mixed pulsation modes of consecutive radial order have been detected for thousands of low-mass red-giant stars with the NASA space telescope Kepler. These modes have the potential to reveal information on the physics of the deep stellar interior. Aims: Different methods have been proposed to derive an observed value for the gravity-mode period spacing, the most prominent one relying on a relation derived from asymptotic pulsation theory applied to the gravity-mode character of the mixed modes. Our aim is to compare results based on this asymptotic relation with those derived from an empirical approach for three pulsating red-giant stars. Methods: We developed a data-driven method to perform frequency extraction and mode identification. Next, we used the identified dipole mixed modes to determine the gravity-mode period spacing by means of an empirical method and by means of the asymptotic relation. In our methodology we consider the phase offset, ∊g, of the asymptotic relation as a free parameter. Results: Using the frequencies of the identified dipole mixed modes for each star in the sample, we derived a value for the gravity-mode period spacing using the two different methods. These values differ by less than 5%. The average precision we achieved for the period spacing derived from the asymptotic relation is better than 1%, while that of our data-driven approach is 3%. Conclusions: Good agreement is found between values for the period spacing derived from the asymptotic relation and from the empirical method. The achieved uncertainties are small, but do not support the ultra-high precision claimed in the literature. The precision from our data-driven method is mostly affected by the differing number of observed dipole mixed modes. For the asymptotic relation, the phase offset, ∊g, remains ill defined, but enables a more robust analysis of both the asymptotic period spacing and the dimensionless coupling factor. However, its estimation might still offer a valuable observational diagnostic for future theoretical modeling.
Volume
588
Start page
A82
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2016A&A...588A..82B
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

aa27055-15.pdf

Description
pdf editoriale
Size

3.12 MB

Format

Adobe PDF

Checksum (MD5)

0b8aff9fcb845031c4570863634957dc