The HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo
The HOSTS Survey: Evidence for an Extended Dust Disk and Constraints on the Presence of Giant Planets in the Habitable Zone of β Leo
复制标题
HOSTS 巡天：尘盘扩展的证据以及对 β 狮子座宜居带内巨行星存在的限制
作者：
D. Defrére;P. Hinz;G. Kennedy;J. Stone;J. Rigley;S. Ertel;A. Gáspár;V. Bailey;W. Hoffmann;B. Mennesson;R. Millan;W. Danchi;O. Absil;P. Arbo;C. Beichman;M. Bonavita;G. Brusa;G. Bryden;E. Downey;S. Esposito;P. Grenz;C. Haniff;J. Hill;J. Leisenring;J. Males;T. Mcmahon;M. Montoya;K. Morzinski;E. Pinna;A. Puglisi;G. Rieke;A. Roberge;H. Rousseau;E. Serabyn;E. Spalding;A. Skemer;K. Stapelfeldt;K. Su;A. Vaz;A. Weinberger;M. Wyatt
年轻的（50-400 Myr） A3V恒星β狮子座是研究太阳系外行星系统形成历史和演化的主要目标，是已知的少数具有热（~ 1600 K），暖（~ 600 K）和冷（~ 120 K）尘埃带成分的恒星之一。在本文中，我们介绍了用大型双目望远镜干涉仪（LBTI）获得的温暖尘埃亮度的深中红外测量结果，作为其外黄道带尘埃调查（HOSTS）的一部分。在β狮子座宜居带以外的1.5 au内，测量到的过剩量为0.47%±0.050%，在4.5 au内上升到0.81%±0.026%。这个尘埃水平是太阳系黄道云的50±10倍。波因廷-罗伯逊拖了斯皮策探测到的冷尘埃，而赫歇尔则低估了β狮子座宜居带中存在的尘埃，这表明在~ 5.5 au处存在额外的传递机制（例如彗星）或额外的带。提供的这些尘埃成分的模型表明，在~ 5 au和~ 40 au的外带之间，不存在比土星质量多几个的行星。我们还利用LBTI成像通道在3.8 μm波段对巨行星进行了观测约束。假设它的年龄是50兆日，那么系统中任何在5-50天文单位之间的行星都必须小于木星的几个质量，这与我们的尘埃模型是一致的。综上所述，这些观测结果展示了LBTI对温暖的外黄道带尘埃和位于附近恒星宜居带或附近的巨大系外行星所能达到的深度对比和探测能力。
The young (50–400 Myr) A3V star β Leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot (∼1600 K), warm (∼600 K), and cold (∼120 K) dust belt components. In this paper, we present deep mid-infrared measurements of the warm dust brightness obtained with the Large Binocular Telescope Interferometer (LBTI) as part of its exozodiacal dust survey (HOSTS). The measured excess is 0.47% ± 0.050% within the central 1.5 au, rising to 0.81% ± 0.026% within 4.5 au, outside the habitable zone of β Leo. This dust level is 50 ± 10 times greater than in the solar system’s zodiacal cloud. Poynting–Robertson drag on the cold dust detected by Spitzer, and Herschel underpredicts the dust present in the habitable zone of β Leo, suggesting an additional delivery mechanism (e.g., comets) or an additional belt at ∼5.5 au. A model of these dust components is provided that implies the absence of planets more than a few Saturn masses between ∼5 au and the outer belt at ∼40 au. We also observationally constrain giant planets with the LBTI imaging channel at 3.8 μm wavelength. Assuming an age of 50 Myr, any planet in the system between approximately 5–50 au must be less than a few Jupiter masses, consistent with our dust model. Taken together, these observations showcase the deep contrasts and detection capabilities attainable by the LBTI for both warm exozodiacal dust and giant exoplanets in or near the habitable zone of nearby stars.
影响因子：
4.8
作者：
B. Yelverton;G. Kennedy;K. Su;M. Wyatt
通讯作者：
B. Yelverton;G. Kennedy;K. Su;M. Wyatt