We report the discovery of the youngest brown dwarf with a disk at 102 pc from the Sun, WISEA~J120037.79-784508.3 (W1200-7845), via the Disk Detective citizen science project. We establish that W1200-7845 is located in the 3.7$\substack{+4.6 \\ -1.4}$ Myr-old $\varepsilon$~Cha association. Its spectral energy distribution (SED) exhibits clear evidence of an infrared (IR) excess, indicative of the presence of a warm circumstellar disk. Modeling this warm disk, we find the data are best fit using a power-law description with a slope $\alpha = -0.94$, which suggests it is a young, Class II type disk. Using a single blackbody disk fit, we find $T_{eff, disk} = 521 K$ and $L_{IR}/L_{*} = 0.14$. The near-infrared spectrum of W1200-7845 matches a spectral type of M6.0$\gamma \pm 0.5$, which corresponds to a low surface gravity object, and lacks distinctive signatures of strong Pa$\beta$ or Br$\gamma$ accretion. Both our SED fitting and spectral analysis indicate the source is cool ($T_{eff} = $2784-2850 K), with a mass of 42-58 $M_{Jup}$, well within the brown dwarf regime. The proximity of this young brown dwarf disk makes the system an ideal benchmark for investigating the formation and early evolution of brown dwarfs.

中文翻译：

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发现附近的年轻褐矮星盘

我们通过 Disk Detective 公民科学项目报告了在 102 pc 处发现最年轻的棕矮星，WISEA~J120037.79-784508.3 (W1200-7845)。我们确定 W1200-7845 位于 3.7$\substack{+4.6 \\ -1.4}$ Myr-old $\varepsilon$~Cha 关联中。它的光谱能量分布 (SED) 显示出红外 (IR) 过剩的明显证据，表明存在温暖的星周盘。对这个温暖的磁盘进行建模，我们发现数据最适合使用斜率 $\alpha = -0.94$ 的幂律描述，这表明它是一个年轻的 II 类磁盘。使用单个黑体圆盘拟合，我们发现 $T_{eff, disk} = 521 K$ 和 $L_{IR}/L_{*} = 0.14$。W1200-7845的近红外光谱匹配M6.0$\gamma\pm 0.5$的光谱类型，对应一个低表面重力物体，并且缺乏强烈的 Pa$\beta$ 或 Br$\gamma$ 吸积的独特特征。我们的 SED 拟合和光谱分析都表明源很冷（$T_{eff} = $2784-2850 K），质量为 42-58 $M_{Jup}$，完全在棕矮星范围内。这个年轻的褐矮星盘的接近度使该系统成为研究褐矮星形成和早期演化的理想基准。