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.

年轻的（50-400 Myr）A3V 恒星β Leo 是研究太阳系外行星系统形成历史和演化的主要目标，它是少数具有已知热（~1600 K）、暖（~600 K）和冷（~120 K）尘带组件。在本文中，我们展示了使用大型双筒望远镜干涉仪 (LBTI) 获得的暖尘埃亮度的深中红外测量，作为其外生肖尘埃调查 (HOSTS) 的一部分。在β Leo宜居带外，在 1.5 au 中心范围内测量到的超额为 0.47% 0.050%，在 4.5 au 范围内上升到 0.81% 0.026% 。这种尘埃水平是太阳系黄道云的 50 10 倍。波印廷-罗伯逊拖着斯皮策探测到的冷尘埃，赫歇尔低估了宜居带中存在的尘埃β Leo，表明在~5.5 au 处有额外的传输机制（例如，彗星）或额外的带。提供了这些尘埃成分的模型，这意味着在~5 au 和~40 au 的外带之间不存在超过几个土星质量的行星。我们还使用 3.8 μ m 波长的 LBTI 成像通道在观测上限制了巨行星。假设年龄为 50 Myr，系统中大约 5-50 au 之间的任何行星都必须小于几个木星的质量，这与我们的尘埃模型一致。综上所述，这些观测结果展示了 LBTI 对附近恒星宜居带内或附近的温暖系外尘埃和巨型系外行星的深度对比和探测能力。