四个疏散星团候选者（Ivanov 2，Ivanov 7，Ivanov 9和Harvard 9）的PPMXL测光研究
PPMXL photometric study of four open cluster candidates (Ivanov 2, Ivanov 7, Ivanov 9 and Harvard 9)
摘要：
首次使用PPMXL数据库估计了四个未经研究的疏散星团候选者-哈佛9号，伊万诺夫2号，伊万诺夫7号和伊万诺夫9号的天体物理参数。每个星团的恒星密度分布和色星等图被用来确定几何结构（星团中心，有限半径，核心和潮汐半径，到太阳的距离，从银河系中心和从银河系平面）。此外，主要的光度参数（年龄，距离模量，颜色过剩，成员，总质量，弛豫时间，光度和质量函数）进行了估计。
英文摘要：
The astrophysical parameters of four unstudied open star cluster candidates - Harvard 9, Ivanov 2, Ivanov 7, and Ivanov 9 - have been estimated for the first time using the PPMXL database. The stellar density distributions and color-magnitude diagrams for each cluster are used to determine the geometrical structure (cluster center, limited radius, core and tidal radii, the distances from the Sun, from the Galactic center and from the Galactic plane). Also, the main photometric parameters (age, distance modulus, color excesses, membership, total mass, relaxation time, luminosity and mass functions) are estimated.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
