标题： ESO SupJup调查第八部分。 年轻L矮星双星的化学特征 显示英文标题

标题： The ESO SupJup Survey VIII. Chemical fingerprints of young L dwarf twins

摘要： 外行星和棕矮星可能不同的形成途径可能在其元素和同位素比率中留下印记。 这项工作是ESO SupJup调查的一部分，该调查旨在通过分析它们的化学和同位素比率来解开超级木星和棕矮星的形成途径。 在本研究中，我们对AB Doradus移动集团中的两个年轻L4矮星，2MASS J03552337+1133437（2M0355）和2MASS J14252798-3650229（2M1425）的大气层进行了表征。 这包括限制它们的化学成分，$^{12}$CO/$^{13}$CO比率，气压-温度剖面，表面重力和旋转速度。 我们获得了这些棕矮星的高分辨率CRIRES+ K波段光谱，并使用大气反演管道进行了分析。 大气模型是使用辐射传输代码petitRADTRANS生成的，我们采用了自由和平衡化学方法，并将其与PyMultiNest采样算法结合以确定最佳拟合。 我们分别在2M0355和2M1425中报告了$^{13}$CO（13.4 & 8.0$\sigma$）和HF（11.6 & 15.8$\sigma$）的可靠检测。 这些物体具有相似的整体大气特性，包括 2M0355 的$^{12}$CO/$^{13}$CO 同位素比率为$95.5\substack{+6.8 \\ -6.4}$，以及 2M1425 的$109.6\substack{+10.6 \\ -9.6}$。 在两种棕矮星中，我们仅发现H$_2^{18}$O（1.1 & 3.0$\sigma$）的微弱迹象，其下限为H$_2^{16}$O/H$_2^{18}$O$\sim$ 1000。 这两个天体似乎接近化学平衡，考虑到主要光谱贡献者。 未来的研究将把它们置于ESO SupJup调查中观测到的其他天体的背景中。 显示英文摘要

摘要： The potentially distinct formation pathways of exoplanets and brown dwarfs may be imprinted in their elemental and isotopic ratios. This work is part of the ESO SupJup Survey, which aims to disentangle the formation pathways of super-Jupiters and brown dwarfs through the analysis of their chemical and isotopic ratios. In this study, we characterize the atmospheres of two young L4 dwarfs, 2MASS J03552337+1133437 (2M0355) and 2MASS J14252798-3650229 (2M1425), in the AB Doradus Moving Group. This involved constraining their chemical composition, $^{12}$CO/$^{13}$CO ratio, pressure-temperature profile, surface gravity, and rotational velocity. We have obtained high-resolution CRIRES+ K-band spectra of these brown dwarfs, which we analyzed with an atmospheric retrieval pipeline. Atmospheric models were generated with the radiative transfer code petitRADTRANS, for which we employed a free and equilibrium chemistry approach, which we coupled with the PyMultiNest sampling algorithm to determine the best fit. We report robust detections of $^{13}$CO (13.4 & 8.0 $\sigma$) and HF (11.6 & 15.8 $\sigma$) in 2M0355 and 2M1425, respectively. The objects have similar overall atmospheric properties, including $^{12}$CO/$^{13}$CO isotope ratios of $95.5\substack{+6.8 \\ -6.4}$ for 2M0355 and $109.6\substack{+10.6 \\ -9.6}$ for 2M1425. In both brown dwarfs, we find only tentative hints of H$_2^{18}$O (1.1 & 3.0 $\sigma$), with lower limits of H$_2^{16}$O/H$_2^{18}$O $\sim$ 1000. Both objects appear to be close to chemical equilibrium, considering the main spectral contributors. Future studies will put them into the context of other objects observed as part of the ESO SupJup Survey.