A&A 492, L49-L52 (2008)

DOI: 10.1051/0004-6361:200809364

*Letter*

## A new asteroseismic diagram of solar-like stars

**Y. K. Tang**

^{1, 2}, S. L. Bi^{3}, and N. Gai^{3}^{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 “*r*_{01}” of adjacent, average, small separations.*Methods. *The ratio *r*_{01} 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 *r*_{01}
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 *r*_{01} 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 *r*_{01}, which can be a useful direct indicator of stellar age.

**Key words:**stars: evolution

**--**stars: oscillations

**©**

*ESO 2008*