ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753
Autor/es:
BRIQUET, M.; KORHONEN, H.; GONZÁLEZ, J.F.; HUBRIG, S.; HACKMAN, T.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2010 vol. 511 p. 1 - 6
ISSN:
0004-6361
Resumen:
Aims: We gathered about 100 high-resolution spectra of three
typical HgMn (mercury-manganese) stars, HD 11753,
HD 53244, and HD 221507, to search
for slowly pulsating B-like pulsations and surface inhomogeneous
distribution of various chemical elements. Methods: Classical
frequency analysis methods were used to detect line profile variability
and to determine the variation period. Doppler imaging reconstruction
was performed to obtain abundance maps of chemical elements on the
stellar surface. Results: For HD 11753, which
is the star with the most pronounced variability, distinct spectral line
profile changes were detected for Ti, Sr, Y, Zr, and Hg, whereas for
HD 53244 and HD 221507 the most
variable line profiles belong to the elements Hg and Y, respectively. We
derived rotation periods for all three stars from the variations of
radial velocities and equivalent widths of spectral lines belonging to
inhomogeneously distributed elements: Prot (HD
11753) = 9.54 d, Prot (HD 53244)
= 6.16 d, and Prot (HD 221507) = 1.93 d.
For HD 11753 the Doppler imaging technique was
applied to derive the distribution of the most variable elements Ti, Sr,
and Y using two datasets separated by ~65 days. Results of Doppler
imaging reconstruction revealed noticeable changes in the surface
distributions of Ti II, Sr II, and Y II between the datasets, indicating
the hitherto not well understood physical processes in stars with
radiative envelopes that cause a rather fast dynamical chemical spot
evolution.
Based on observations obtained with the CORALIE Echelle Spectrograph on
the 1.2-m Euler Swiss telescope, situated at La Silla,
Chile.Postdoctoral Fellow of the Fund for Scientific Research, Flanders.