标题： 快速自转的delta Scuti星Rasalhague（天蝎座α）中旋转调制的g模 显示英文标题

标题： Rotationally-modulated g-modes in the rapidly-rotating delta Scuti star Rasalhague (alpha Ophiuchi)

摘要： 尽管在理解恒星内部方面已经取得了一个世纪的显著进展，但我们对接近其临界极限旋转的恒星内部工作机制却知之甚少。 对这些所谓的“快速自转者”进行的新干涉成像，结合天琴座振荡学的突破性进展，有望揭开这一层面，并探测纬度依赖性强的光球特性，甚至揭示这些明亮天体的内部角动量分布。 在这里，我们报告了基于MOST卫星连续30天监测数据，针对低振幅δ Scuti变星Rasalhague（α Oph，A5IV，2.18 M☉，ω/ωc~0.88）的首次高精度测光观测结果。 我们已经在具有约26天截止频率的随机粒状光谱之上识别出57±1个明显的脉动模式。 令人惊讶的是，我们还发现快速自转周期（14.5小时）会调制低频模式（1-10天周期），这些模式被识别为丰富的g模式家族（|m|高达7）。 考虑到科里奥利力预计会严重扭曲模式光谱，g模式间距的线性程度令人惊讶，这表明我们正在观察前进的“赤道科里奥利”波（模式l=m）。 我们强调了Rasalhague的独特之处，激励未来详细的天琴座振荡学建模——一个具有精确测量视差距离、光球扁率、纬度温度结构的源，且其低质量伴星提供了用于精确质量测定的天文学轨道。 显示英文摘要

摘要： Despite a century of remarkable progress in understanding stellar interiors, we know surprisingly little about the inner workings of stars spinning near their critical limit. New interferometric imaging of these so-called ``rapid rotators'' combined with breakthroughs in asteroseismology promise to lift this veil and probe the strongly latitude-dependent photospheric characteristics and even reveal the internal angular momentum distribution of these luminous objects. Here, we report the first high precision photometry on the low-amplitude delta cuti variable star Rasalhague (alpha Oph, A5IV, 2.18 Msun, omega/omega_c~0.88) based on 30 continuous days of monitoring using the MOST satellite. We have identified 57+/-1 distinct pulsation modes above a stochastic granulation spectrum with a cutoff of ~26 cycles per day. Remarkably, we have also discovered that the fast rotation period of 14.5~hours modulates low-frequency modes (1-10 day periods) that we identify as a rich family of g-modes (|m| up to 7). The spacing of the g-modes is surprisingly linear considering Coriolis forces are expected to strongly distort the mode spectrum, suggesting we are seeing prograde ``equatorial Kelvin'' waves (modes l=m). We emphasize the unique aspects of Rasalhague motivating future detailed asteroseismic modeling -- a source with a precisely measured parallax distance, photospheric oblateness, latitude temperature structure, and whose low-mass companion provides an astrometric orbit for precise mass determinations.