利用HERMES光谱与TESS测光研究大质量恒星的脉动与双星性的协同作用
The symphony of pulsations and binarity among massive stars using HERMES spectroscopy and TESS photometry
AI总结：
本研究结合HERMES光谱与TESS测光，对873颗O/B型大质量恒星开展变光调查，明确多数样本存在脉动或双星性变异性，为恒星结构演化研究提供统计框架。
AI中文摘要：
中等质量与大质量恒星中存在多种尚未完全明确的变光机制。我们针对大量B型与O型恒星，结合互补数据源，旨在研究双星性、脉动、自转等不同类型变光的普遍性与相互作用，为后续建模做准备。为此，我们分析高分辨率HERMES光谱与2分钟采样的TESS测光数据，表征873颗O型与B型恒星观测到的多样变光现象。光谱数据通过机器学习技术归一化，与TLUSTY合成光谱网格比对以确定恒星参数，并用于识别视向速度变异性。测光时间序列采用标准频率分析方法，以检测脉动与自转调制信号。我们发现，超过93%的样本存在测光变异性；其中82%的样本存在脉动导致的测光变异性，主要贡献来自β Cep型恒星、慢脉动B型恒星以及随机低频变异性。基于有限的光谱观测epoch，至少14%的恒星呈现双星性证据，包含食双星与分光双星系统。本研究是北半球针对中等质量与大质量恒星开展的最大规模同质变光调查之一，可与南半球类似研究形成互补，为未来恒星结构与演化研究（尤其 asteroseismology 领域）提供统计框架。
英文摘要：
A wide range of variability mechanisms exist among intermediate mass and massive stars, which are not yet fully understood. Using complementary data sources for a large population of B- and O-type stars, we aim to study the prevalence and interplay of different types of variability, including binarity, pulsation, and rotation, to prepare for future modelling. To this end, we analyse high-resolution HERMES spectra and 2-min cadence TESS photometry and characterise the diverse variability observed within a population of 873 O- and B-type stars. The spectroscopic data were normalised using machine-learning techniques, compared to a grid of synthetic TLUSTY spectra to determine stellar parameters, and used to identify radial velocity variability. Photometric time series were analysed using standard frequency analysis methods to detect pulsations and rotational modulation signatures. We find that more than 93 per cent of the sample exhibits photometric variability. Photometric variability caused by pulsations is identified in 82 per cent of the sample, with dominant contributions from $β$ Cep and slowly pulsating B-type stars, as well as stochastic low-frequency variability. Based on a limited number of spectroscopic epochs, at least 14 per cent of the stars show evidence of binarity, including both eclipsing and spectroscopic systems. This work represents one of the largest homogeneous surveys of variability for intermediate-mass and massive stars in the Northern hemisphere, and complementing similar efforts in the Southern hemisphere. It provides a statistical framework for future studies of stellar structure and evolution, particularly in the context of asteroseismology.
