INVESTIGADORES
CORSICO Alejandro Hugo
artículos
Título:
An independent limit on the axion mass from the variable white dwarf star R548
Autor/es:
A. H. CÓRSICO; L. G. ALTHAUS; A. D. ROMERO; A. S. MUKADAM; E. GARCÍA-BERRO; S. O. KEPLER; M. A. CORTI
Revista:
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
Editorial:
IOP PUBLISHING LTD
Referencias:
Lugar: Londres; Año: 2012 vol. 12 p. 10 - 20
ISSN:
1475-7516
Resumen:
Pulsating white dwarfs with hydrogen-rich atmospheres, also known as DAV
stars, can be used as astrophysical laboratories to constrain the
properties of fundamental particles like axions. Comparing the measured
cooling rates of these stars with the expected values from theoretical
models allows us to search for sources of additional cooling due to the
emission of weakly interacting particles. In this paper, we present an
independent inference of the mass of the axion using the recent
determination of the evolutionary cooling rate of R548, the DAV class
prototype. We employ a state-of-the-art code which allows us to perform
a detailed asteroseismological fit based on fully evolutionary
sequences. Stellar cooling is the solely responsible of the rates of
change of period with time (\dot\Pi}) for the DAV class. Thus, the
inclusion of axion emission in these sequences notably influences the
evolutionary timescales, and also the expected pulsational properties of
the DAV stars. This allows us to compare the theoretical \dot\Pi} values
to the corresponding empirical rate of change of period with time of
R548 to discern the presence of axion cooling. We found that if the
dominant period at 213.13 s in R548 is associated with a pulsation mode
trapped in the hydrogen envelope, our models indicate the existence of
additional cooling in this pulsating white dwarf, consistent with axions
of mass macos 2β ~ 17.1 meV at a 2σ
confidence level. This determination is in agreement with the value
inferred from another well-studied DAV, G117-B15A. We now have two
independent and consistent estimates of the mass of the axion obtained
from DAVs, although additional studies of other pulsating white dwarfs
are needed to confirm this value of the axion mass.