Berkeley 29, the most distant old open cluster
Berkeley 29, the most distant old open cluster
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Berkeley 29，最遥远的古老疏散星团
DOI：
10.1111/j.1365-2966.2004.08184.x
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发表时间：
2004
影响因子：
4.8
通讯作者：
G. Marconi
中科院分区：
文献类型：
--
作者：
M. Tosi;L. Fabrizio;A. Bragaglia;P. A. Carusillo;G. Marconi
我们对位于反中心方向的老疏散星团（OC） Berkeley 29进行了CCD BVI光度测量。利用合成色星等图（CMDs）技术，我们同时估计了它的年龄、变红程度、距离和三种恒星演化轨迹的近似金属丰度。根据所采用的恒星模型，最佳解为：年龄= 3.4或3.7 Gyr, (m - m) 0 = 15.6或15.8，E(B - V) = 0.13或0.10，金属丰度低于太阳（Z = 0.006或0.004）。利用这些推导值，Be 29被证明是已知最远的OC，其星系中心距离R GC = 21.4至22.6 kpc。因此，be29定性地遵循年龄-金属丰度关系和典型的银盘天体的金属丰度梯度。然而，星团的位置和径向速度似乎将Be 29与大犬座碎片家族联系起来。
We present CCD BVI photometry of the old open cluster (OC) Berkeley 29, located in the anticentre direction. Using the synthetic colour-magnitude diagrams (CMDs) technique we estimate at the same time its age, reddening, distance and approximate metallicity using three types of stellar evolutionary tracks. The best solutions give: age = 3.4 or 3.7 Gyr, (m - M) 0 = 15.6 or 15.8 with E(B - V) = 0.13 or 0.10, and metallicity lower than solar (Z = 0.006 or 0.004), depending on the adopted stellar models. Using these derived values, Be 29 turns out to be the most distant OC known, with Galactocentric distance R GC = 21.4 to 22.6 kpc. Hence, Be 29 qualitatively follows both the age-metallicity relation and the metal abundance gradient typical of Galactic disc objects. The cluster position and radial velocity, however, appear to link Be 29 to the family of the Canis Maior debris.