Letter to the Editor

A new asteroseismic diagram of solar-like stars

¹ Department of Physics, Dezhou University, Dezhou 253023, PR China e-mail: tyk450@163.com; bisl@bnu.edu.cn
² Key Lab of Biophysics in Universities of Shandong, Dezhou 253023, PR China
³ Department of Astronomy, Beijing Normal University, Beijing 100875, PR China

Received: 8 January 2008
Accepted: 13 November 2008

Abstract

Aims. We attempt to develop a new asteroseismic diagram and investigate its characteristics, based on the ratio “r₀₁” of adjacent, average, small separations.

Methods. The ratio r₀₁ is defined following the asymptotic formula of stellar p-modes. Using the low-degree, theoretical, numerical value of adiabatic frequencies of stellar model, we compute the ratio r₀₁ and construct an additional asteroseismic diagram.

Results. The additional asteroseismic diagram, which is similar to the C-D diagram (i.e. the famous asteroseismic HR diagram, so-called Christensen-Dalsgaard diagram), represents a composite of the average, large separations and the ratio r₀₁ of the adjacent, small separations. A distinct separation is identified between the effects of varying both mass and age. The diagram can therefore provide information that is complementary to that provided by a C-D diagram, which can be used to estimate directly both the stellar mass and evolutionary state. Interestingly, the age of star can be derived from the new asteroseismic diagram. Furthermore, we investigate the parameter r₀₁, which can be a useful direct indicator of stellar age.