We present parallax and proper motion measurements, near-infrared spectra, and WISE photometry for the low surface gravity L5γ dwarf 2MASSJ035523.37+113343.7 (2M0355). We use these data to evaluate photometric, spectral, and kinematic signatures of youth as 2M0355 is the reddest isolated L dwarf yet classified. We confirm its low-gravity spectral morphology and find a strong resemblance to the sharp triangular shaped H-band spectrum of the ∼10 Myr planetary-mass object 2M1207b. We find that 2M0355 is underluminous compared to a normal field L5 dwarf in the optical and MKO J, H, and K bands and transitions to being overluminous from 3-12 μm, indicating that enhanced photospheric dust shifts flux to longer wavelengths for young, low-gravity objects, creating a red spectral energy distribution. Investigating the near-infrared color magnitude diagram for brown dwarfs confirms that 2M0355 is redder and underluminous compared to the known brown dwarf population, similar to the peculiarities of directly imaged exoplanets 2M1207b and HR8799bcd. We calculate UVW space velocities and find that the motion of 2M0355 is consistent with young disk objects (< 2-3 Gyr) and it shows a high likelihood of membership in the AB Doradus association.

中文翻译：

---

2MASS J035523.37+113343.7：一颗年轻的、尘土飞扬的、附近的、孤立的棕矮星，类似于一颗巨大的系外行星

我们展示了低表面重力 L5γ 矮星 2MASSJ035523.37+113343.7 (2M0355) 的视差和自行测量、近红外光谱和 WISE 光度测量。我们使用这些数据来评估年轻的光度、光谱和运动学特征，因为 2M0355 是迄今为止分类的最红的孤立 L 矮星。我们确认了它的低重力光谱形态，并发现它与 ∼10 Myr 行星质量物体 2M1207b 的尖锐三角形 H 波段光谱非常相似。我们发现，与正常场 L5 矮星相比，2M0355 在光学和 MKO J、H 和 K 波段中发光度较低，并且从 3-12 μm 过渡到发光度过高，这表明增强的光球尘埃将通量转移到了年轻、低光的更长波长。 -重力物体，产生红色光谱能量分布。研究褐矮星的近红外颜色星等图证实，与已知的褐矮星群相比，2M0355 更红且亮度较低，类似于直接成像的系外行星 2M1207b 和 HR8799bcd 的特性。我们计算了 UVW 空间速度，发现 2M0355 的运动与年轻的盘状物体（< 2-3 Gyr）一致，并且它显示出 AB Doradus 协会成员资格的可能性很高。