HD54236 is a nearby, wide common-proper-motion visual pair that has been previously identified as likely being very young by virtue of strong X-ray emission and lithium absorption. Here, we report the discovery that the brighter member of the wide pair, HD54236A, is itself an eclipsing binary (EB), comprising two near-equal solar-mass stars on a 2.4 days orbit. It represents a potentially valuable opportunity to expand the number of benchmark-grade EBs at young stellar ages. Using new observations of Ca iiH and K emission and lithium absorption in the wide K-dwarf companion, HD54236B, we obtain a robust age estimate of 22550 Myr for the system. This age estimate and Gaia proper motions show HD54236 is associated with Theia301, a newly discovered local “stellar string,” which itself may be related to the ABDor moving group through shared stellar members. Applying this age estimate to ABDor itself alleviates reported tension between observation and theory that arises for the luminosity of ABDorC when younger age estimates are used.

HD54236 是一种附近的、广泛的、广泛的、常见的适当运动的视觉对，之前由于强烈的 X 射线发射和锂吸收，它被认为可能非常年轻。在这里，我们报告了这一发现，即宽对中较亮的成员 HD54236A 本身就是一个食双星 (EB)，由两颗太阳质量接近 2.4 天的恒星组成。它代表了在年轻恒星时代扩大基准级 EB 数量的潜在宝贵机会。使用 Ca ii 的新观测值在宽 K 矮星伴星 HD54236B 中的 H 和 K 发射和锂吸收，我们获得了该系统 22550 Myr 的可靠年龄估计。这个年龄估计和盖亚自行显示 HD54236 与 Theia301 相关，这是一个新发现的本地“星弦”，它本身可能通过共享的恒星成员与 ABDor 移动群有关。将这个年龄估计应用于 ABDor 本身可以缓解所报告的观察和理论之间的紧张关系，当使用更年轻的年龄估计时，ABDorC 的光度会引起观察和理论之间的紧张。