The star Eta Ophiuchi. It appears to the naked eye of magnitude 2.4, but it is in fact a close binary consisting of two A-type dwarfs of magnitudes 3.0 and 3.5 that orbit with a period of 88 years. It lies 88 l.y. away.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。