Detalles de publicación
PP 011064
The excitation of solar-like oscillations in a delta Sct star by efficient envelope convection
(1) Uni. Vienna, (2) Copernicus Astronomical Center, (3) Uni. Porto, (4) Uni. Aarhus, (5) NOT, (6) CAB INTA-CSI, (7) Uni. British Columbia, (8) KULeuven, (9) Uni. Sydney, (10) INAF-Catania, (11) ROB, (12) CEA Saclay, (13) KIS, (14) IAC, ULL, (15) UCLAN, (16) SETI institute, NASA Ames, (17) Orbital Sciences Corporation, NASA Ames
Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses
of 1.5-2.5MSun, their pulsations resulting from the varying ionization of
helium. In less massive stars such as the Sun, convection transports mass
and energy through the outer 30 per cent of the star and excites a rich
spectrum of resonant acoustic modes. Based on the solar example, with
no firm theoretical basis, models predict that the convective envelope
in delta Sct stars extends only about 1 per cent of the radius, but with
sufficient energy to excite solar-like oscillations. This was not observed
before the Kepler mission, so the presence of a convective envelope in the
models has been questioned. Here we report the detection of solar-like
oscillations in the delta Sct star HD 187547, implying that surface convection
operates efficiently in stars about twice as massive as the Sun, as the ad
hoc models predicted.
of 1.5-2.5MSun, their pulsations resulting from the varying ionization of
helium. In less massive stars such as the Sun, convection transports mass
and energy through the outer 30 per cent of the star and excites a rich
spectrum of resonant acoustic modes. Based on the solar example, with
no firm theoretical basis, models predict that the convective envelope
in delta Sct stars extends only about 1 per cent of the radius, but with
sufficient energy to excite solar-like oscillations. This was not observed
before the Kepler mission, so the presence of a convective envelope in the
models has been questioned. Here we report the detection of solar-like
oscillations in the delta Sct star HD 187547, implying that surface convection
operates efficiently in stars about twice as massive as the Sun, as the ad
hoc models predicted.