飞鱼-船底座星协：年轻与年老恒星族群之间的X射线桥梁
The Volans-Carina association An X-ray Bridge Between Younger and Older Stellar Populations
浏览论文内容
中文总结 AI 辅助
该研究重新评估飞鱼-船底座星协的成员，结合多波段数据与X射线观测确定其年龄为80±20百万年，其X射线特性为恒星磁活动演化研究提供了可靠校准点。
中文摘要 AI 辅助
邻近年轻运动群（NYMGs）为研究早期恒星年龄阶段的磁活动演化与行星环境提供了基准。飞鱼-船底座星协（VCA）是一个距离约90秒差距的前主序星协，占据了年轻邻近星协与年老疏散星团之间参数空间中采样稀疏的区域。我们使用BANYAN工具结合盖亚（Gaia）DR3更新的运动学数据，重新评估了Gagne等人（2018a）提供的VCA星表成员概率；通过多波段光谱能量分布推导恒星参数，结合所得的热光度与有效温度，利用前主序演化模型计算出该星协的等时年龄。我们整合了SRG（Spectrum Roentgen Gamma）/eROSITA与ROSAT全天 surveys的数据，以及专门的XMM-牛顿大项目数据，构建了一份全面的X射线星表。我们更新后的VCA星表包含29个高概率成员、30个候选成员和4个不确定天体。该星协的等时分析得出年龄为80±20百万年，与此前估计一致。我们探测到56个天体的X射线辐射， completeness约达90%，是NYMGs中最完整的X射线普查之一；质量小于0.6倍太阳质量的低质量成员与候选成员，其X射线热光度比约为经典饱和极限（Lx/Lbol≈10^-3）。X射线光度函数显示，VCA（F5至M3型）与年龄相近的昴星团一致，且比年老的毕星团（F5至K4型）活跃得多。更新后的成员普查与近乎完整的X射线普查相结合，使VCA成为日冕X射线活动早期演化研究中特别可靠的校准点。
英文摘要
Nearby young moving groups (NYMGs) provide benchmarks for studying the evolution of magnetic activity and planetary environments at early ages. The Volans-Carina association (VCA), as a pre-main sequence association at a distance of ~90 pc, occupies a sparsely sampled region of parameter space between younger nearby associations and older distant open clusters. We have re-evaluated the membership probabilities of the VCA catalog presented in Gagne et al. (2018a) with BANYAN as well as updated kinematics from Gaia DR3. Stellar parameters were derived from multi-wavelength spectral energy distributions, with the obtained bolometric luminosity and effective temperature being used in combination with pre-main sequence evolutionary models to obtain an isochronal age of the association. We joined data from the SRG (Spectrum Roentgen Gamma)/eROSITA and ROSAT all-sky surveys with a dedicated XMM-Newton Large Programme to construct a comprehensive X-ray catalog. Our updated census of the VCA comprises 29 highly probable members, 30 candidate members, and four uncertain objects. Isochronal analysis of the association yields an age of 80+-20 Myr, consistent with previous estimates. We detect X-ray emission from 56 objects, reaching ~90% completeness, one of the most complete X-ray censuses achieved for a NYMG. Low-mass members and candidates (<0.6 Msolar) have X-ray to bolometric luminosity ratios around the canonical saturation limit (Lx/Lbol~10^-3). X-ray luminosity functions show the VCA to be consistent with the similarly aged Pleiades (in the F5 to M3 range) and significantly more active than the older Hyades (in the F5 to K4 range). The combination of an updated membership census and a nearly complete X-ray census establishes the VCA as a particularly robust calibration point for studies of the early evolution of coronal X-ray activity.
