Article (Scientific journals)
A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf
Giammichele, Noemi; Charpinet, Stéphane; Fontaine, Gilles et al.
2018In Nature, 554, p. 73
Peer Reviewed verified by ORBi
 

Files


Full Text
Giammichele_et_al-2018-Nature.pdf
Publisher postprint (3.28 MB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Abstract :
[en] White-dwarf stars are the end product of stellar evolution for most stars in the Universe1. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution2,3. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles4. However, the internal structure of white-dwarf stars—in particular their oxygen content and the stratification of their cores—is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes5,6. Here we report a measurement of the radial chemical stratification (of oxygen, carbon and helium) in the hydrogen- deficient white-dwarf star KIC08626021 (J192904.6+444708), independently of stellar-evolution calculations. We use archival data7,8 coupled with asteroseismic sounding techniques9,10 to determine the internal constitution of this star. We find that the oxygen content and extent of its core exceed the predictions of existing models of stellar evolution. The central homogeneous core has a mass of 0.45 solar masses, and is composed of about 86 per cent oxygen by mass. These values are respectively 40 per cent and 15 per cent greater than those expected from typical white-dwarf models. These findings challenge present theories of stellar evolution and their constitutive physics, and open up an avenue for calibrating white-dwarf cosmochronology11.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Giammichele, Noemi
Charpinet, Stéphane
Fontaine, Gilles
Brassard, Pierre
Green, Elizabeth M.
Van Grootel, Valérie  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Bergeron, Pierre
Zong, Weikai
Dupret, Marc-Antoine ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Language :
English
Title :
A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf
Publication date :
February 2018
Journal title :
Nature
ISSN :
0028-0836
eISSN :
1476-4687
Publisher :
Nature Publishing Group, Basingstoke, United Kingdom
Volume :
554
Pages :
73
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 09 January 2018

Statistics


Number of views
231 (23 by ULiège)
Number of downloads
348 (10 by ULiège)

Scopus citations®
 
75
Scopus citations®
without self-citations
57
OpenCitations
 
57

Bibliography


Similar publications



Contact ORBi