猎户座星云周围的前主序B型星
Pre-main Sequence B Stars Surrounding the Orion Nebula
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中文总结 AI 辅助
研究旨在确定猎户座星云周围B型和早A型恒星的光谱类型、质量和年龄以找PMS候选者，结合光学和近红外光谱及多源测光，经多种方法得出相关数据，识别出候选者，完善了年轻恒星普查，其年龄分布为星形成历史提供线索。
中文摘要 AI 辅助
前主序（PMS）早期型恒星因其快速演化而稀少，确认PMS B型星对限制高质量恒星形成情景很有价值。尽管猎户座星云区域为此类研究提供了理想场所，但其B型星群体特征仍不明晰。我们旨在确定猎户座星云周围B型和早A型恒星的光谱类型、质量和年龄，以识别可靠的PMS候选者。我们结合光学和近红外光谱，利用 Brackett、He、Si和Mg线估计光谱类型，通过盖亚、2MASS和WISE的测光构建颜色-星等图，经卡方最小化拟合等时线得出恒星年龄和质量，还用食双星的动力学质量作为对各光谱亚型质量范围的独立约束。我们得出了53颗恒星的年龄和质量，48颗的光谱分类，识别出30个PMS候选者，包括一些先前被归为I-III光度级别的恒星。几颗恒星显示出光谱变化，可能与星周物质或双星有关。我们的光谱和测光结合方法识别出可靠的PMS B型星候选者，并提供了一个将它们与演化恒星区分开的有效框架，完善了猎户座早期型年轻恒星的普查。PMS候选者的年龄分布为猎户座星云区域的恒星形成历史提供了初步线索。
英文摘要
Pre-main sequence (PMS) early-type stars are rare due to their rapid evolution. Confirming PMS B stars is accordingly valuable for constraining higher mass star formation scenarios. Although the Orion Nebula (ON) region offers an ideal laboratory for such studies, its population of B stars remains poorly characterized. We aim to determine spectral types, masses, and ages of B and early A stars surrounding the ON, to identify robust PMS candidates. We combine optical and near-infrared spectroscopy to estimate spectral types using Brackett, He, Si, and Mg lines. Photometry from Gaia, 2MASS, and WISE is used to construct colour-magnitude diagrams to fit isochrones via chi-square minimisation, yielding stellar ages and masses. Dynamical masses from eclipsing binaries are employed as independent constraints on the mass range allowed for each spectral subtype. We derive stellar ages and masses for 53 stars and spectral classifications for 48 of them, identifying 30 PMS candidates, including some that were previously assigned to luminosity classes I-III. Several stars show spectroscopic variability, potentially linked to circumstellar material or binarity. Our combined spectroscopic and photometric approach identifies robust PMS B-star candidates and provides a validated framework for distinguishing them from evolved counterparts - in this instance, refining the census of early-types young stars in Orion. The age distribution of the PMS candidates offers preliminary clues about the star formation history of the ON region.
