中文摘要：

根据最近发表的新编依巴谷星表数据，重新研究了经典造父变星周光关系零点问题．利用运动学模型对自行数据和视向速度分别拟合奥尔特常数及本地静止标准的旋转速度，得到太阳的银心距R0=8．0±0．8kpc．从太阳附近的旋转曲线，发现银河系盘的引力势具有弱椭圆分布的迹象．通过一个简单的非对称模型，得到太阳附近盘引力势的椭率ε（Ro）=0．067±0．036，其短轴指向φb=32°±15°．

英文摘要：

On the basis of the revised Hipparcos data recently released, the zero-point of the PL relation for classical cepheids was reexamined. Fitting proper motion and radial velocity data via an axis symmetric model, Oort constants and circular rotation velocity of the LSR were calculated to obtain Galactocentric distance of the sun, R0= 8.0±0.8kpc. From the rotation curve in solar neighborhood, the existence of weak ellipticity of the Galactic potential was found. Adopting a simple asymmetric model, we obtained the ellipticity ε（R0） = 0.067± 0.036 at the sun, while the minor axis pointing to φb=32°±15°.