AI 中文总结
本研究表征了TESS发现的、围绕大质量A型恒星HIP 61637运行的近圆轨道褐矮星HIP 61637 b，精确测定其参数与系统年龄，为亚恒星演化模型测试提供关键数据。
AI 中文摘要
我们对HIP 61637 b（TOI-5401 b）进行了表征，这是一颗由TESS发现的、凌星A型恒星的褐矮星。HIP 61637是迄今为止已知的拥有凌星褐矮星的恒星中质量最大、亮度最高的，该伴星位于“褐矮星沙漠”的中间区域。我们对NASA的TESS任务获取的光变曲线以及我们用Tillinghast Reflector Echelle Spectrograph获取的高分辨率光谱进行了联合分析，确定HIP 61637 b的半径为$R_{BD}=1.149^{+0.049}_{-0.038}R_J$，质量为$M_{BD}=47.8^{+1.5}_{-1.4}M_J$，每$6.829104\balpha\beta\theta\rho$±0.000011天凌星一次，轨道近圆（$e=0.054\balpha\beta\theta\rho$±0.013）。主星质量为2.86±0.12$M_\theta$，半径为4.33±0.17$R_\theta$，有效温度为$T_{\text{eff}}=9180^{+240}_{-230}$K。我们发现该主星接近主序阶段末期，已开始演化，利用恒星演化模型可精确估计该系统的年龄为396±46百万年。这为少数具有可靠年龄估计、表征良好的凌星褐矮星增添了一个重要数据点，使我们能够测试最新的亚恒星演化模型。潮汐演化理论预测，潮汐耗散机制已使轨道圆化，与观测到的近零偏心率一致。
英文摘要
We present the characterization of HIP 61637 b (TOI-5401 b), a brown dwarf discovered by TESS to transit an A-type star. HIP 61637 is the most massive and the brightest star known to host a transiting brown dwarf to date. The companion lies in the middle of the "brown dwarf desert". We perform a joint analysis of light curves from NASA's TESS mission and our high-resolution spectroscopy from the Tillinghast Reflector Echelle Spectrograph. We determine that HIP 61637 b has a radius of $R_{BD} = 1.149^{+0.049}_{-0.038}$ $R_J$, a mass of $M_{BD} = 47.8^{+1.5}_{-1.4}$ $M_J$, and transits its host star every $6.829104 \pm 0.000011$ days in a near-circular orbit ($e = 0.054 \pm 0.013$). The host star has a mass of $2.86\pm 0.12\,M_\odot$, a radius of $4.33 \pm 0.17\, R_\odot$, and an effective temperature of $T_{\text{eff}} = 9180^{+240}_{-230}$ K. We find that the host is nearing the end of its time on the main sequence and has begun to evolve, allowing for a precise age estimation of $396 \pm 46$ Myr for the system using stellar evolution models. This adds an important data point to the handful of well-characterized transiting brown dwarfs with reliable age estimates, allowing us to test the latest substellar evolution models. Theory of tidal evolution predicts that tidal dissipation mechanisms have circularized the orbit, consistent with the observed near-zero eccentricity.
Comments14 pages, Submitted to The Astronomical Journal
