التفاصيل البيبلوغرافية
| العنوان: |
Suppression of Quadrupole and Octupole Modes in Red Giants Observed by Kepler |
| المؤلفون: |
Stello, Dennis, Cantiello, Matteo, Fuller, Jim, Garcia, Rafael A., Huber, Daniel |
| المصدر: |
Publications of the Astronomical Society of Australia, 33, Art. No. e011, (2016-03-16) |
| بيانات النشر: |
CSIRO Publishing |
| سنة النشر: |
2016 |
| المجموعة: |
Caltech Authors (California Institute of Technology) |
| مصطلحات موضوعية: |
stars: fundamental parameters — stars: oscillations — stars: interiors — stars: magnetic field |
| الوصف: |
An exciting new theoretical result shows that observing suppression of dipole oscillation modes in red giant stars can be used to detect strong magnetic fields in the stellar cores. A fundamental facet of the theory is that nearly all the mode energy leaking into the core is trapped by the magnetic greenhouse effect. This results in clear predictions for how the mode visibility changes as a star evolves up the red giant branch, and how that depends on stellar mass, spherical degree, and mode lifetime. Here, we investigate the validity of these predictions with a focus on the visibility of different spherical degrees. We find that mode suppression weakens for higher degree modes with a reduction in the quadrupole mode visibility of up to 49%, and no detectable suppression of octupole modes, in agreement with theory. We find evidence for the influence of increasing mode lifetimes on the visibilities along the red giant branch, in agreement with previous independent observations. These results support the theory that strong internal magnetic fields cause suppression of non-radial modes in red giants. We also find preliminary evidence that stars with suppressed dipole modes on average have slightly lower metallicity than normal stars. ; © 2016 Astronomical Society of Australia. Received January 19 2016; Accepted February 12 2016. We acknowledge the entire Kepler team, whose efforts made these results possible. D.S. is the recipient of an Australian Research Council Future Fellowship (project number FT140100147). J.F. acknowledges support from NSF under grant no. AST-1205732 and through a Lee DuBridge Fellowship at Caltech. R.A.G. acknowledge the support of the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 269194 (IRSES/ASK), the ANR- IDEE (n ANR-12-BS05-0008), and from the CNES. D.H. acknowledges support by the Australian Research Council's Discovery Projects funding scheme (project number DE140101364) and support by the National Aeronautics and Space Administration ... |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| العلاقة: |
http://arxiv.org/abs/1602.05193Test; https://doi.org/10.1017/pasa.2016.9Test; oai:authors.library.caltech.edu:wp4tk-src20; eprintid:66033; resolverid:CaltechAUTHORS:20160408-143954572 |
| DOI: |
10.1017/pasa.2016.9 |
| الإتاحة: |
https://doi.org/10.1017/pasa.2016.9Test |
| حقوق: |
info:eu-repo/semantics/openAccess ; Other |
| رقم الانضمام: |
edsbas.7F557799 |
| قاعدة البيانات: |
BASE |
