论文标题
Betelgeuse在2019/2020年度昏暗时的光电温度：无需新的灰尘
The Photospheric Temperatures of Betelgeuse during the Great Dimming of 2019/2020: No New Dust Required
论文作者
论文摘要
塑造红色超级巨人（RSG）扩展大气层的过程，加热其色球球，产生分子储层，驱动质量损失并造成尘埃的理解不足。 Betelgeuse的V波段“大调”活动于2019年9月 /2020年2月及其随后的快速增光提供了一个难得的研究这些现象的机会。已经出现了两种不同的解释来解释调查。在我们的视线中出现了新的灰尘，从而削弱了光球光，或者很大一部分光球冷却了。在这里，我们提出了五年的翼三过滤器（A，B和C带）TIO和在Wasatonic天文台获得的近IR光度法。这些表明，光球的一部分具有平均有效温度$（t _ {\ rm eff} $）的平均有效温度，明显低于（Levesque＆Massey 2020）。来自MARCS-MODEL PHOTHUSPHERES和SPESTRA的合成光度法表明，如果有多个光电组件，则V频段，TIO索引和C波段光度法以及以前报道的4000-6800 Angstrom Spectra可以定量复制，如VLT-Sphere Images（Montarge et et al.2020）所暗示的。如果冷却器组件具有$δT_ {\ rm eff} \ ge 250 $ k凉爽的速度比3650 K，则不需要新的灰尘来解释可用的经验约束。主要的短 - （$ \ sim 430美元）和长期（$ \ sim 5.8 $ yr）V波段变化的巧合发生在深度最低时（Guinan等人，2019年）。这与Dupree等人最近报道，这与V MAG和光电径向速度的强相关性相关。 （2020b）。这些表明，可见恒星的大部分的冷却具有与光球运动有关的动态起源，这可能是由于脉动或大规模对流运动引起的。
The processes that shape the extended atmospheres of red supergiants (RSGs), heat their chromospheres, create molecular reservoirs, drive mass loss, and create dust remain poorly understood. Betelgeuse's V-band "Great Dimming" event of 2019 September /2020 February and its subsequent rapid brightening provides a rare opportunity to study these phenomena. Two different explanations have emerged to explain the dimming; new dust appeared in our line of sight attenuating the photospheric light, or a large portion of the photosphere had cooled. Here we present five years of Wing three-filter (A, B, and C band) TiO and near-IR photometry obtained at the Wasatonic Observatory. These reveal that parts of the photosphere had a mean effective temperature $(T_{\rm eff}$) significantly lower than that found by (Levesque & Massey 2020). Synthetic photometry from MARCS -model photospheres and spectra reveal that the V band, TiO index, and C-band photometry, and previously reported 4000-6800 Angstrom spectra can be quantitatively reproduced if there are multiple photospheric components, as hinted at by VLT-SPHERE images (Montarges et al. 2020). If the cooler component has $ΔT_{\rm eff} \ge 250$ K cooler than 3650 K, then no new dust is required to explain the available empirical constraints. A coincidence of the dominant short- ($\sim 430$ day) and long-period ($\sim 5.8$ yr) V-band variations occurred near the time of deep minimum (Guinan et al. 2019). This is in tandem with the strong correlation of V mag and photospheric radial velocities, recently reported by Dupree et al. (2020b). These suggest that the cooling of a large fraction of the visible star has a dynamic origin related to the photospheric motions, perhaps arising from pulsation or large-scale convective motions.
