arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 1502.04707astro-ph.SR
收藏

在T/Y跃迁时发现低光度、致密的亚恒星双星

Discovery of a Low-Luminosity, Tight Substellar Binary at the T/Y Transition

Trent J. Dupuy, Michael C. Liu, S. K. Leggett

备注：
Accepted to ApJ (2015 Feb 14); 24 pages, 4 figures, 5 tables
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

利用凯克激光导星自适应光学成像技术，我们发现了褐矮星WISEJ 014656.66 +423410.0是一个近距离双星（0.0875 $\pm$ 0.0021 arcsec，0.93 $^{+0.12}_{-0.16}$ AU）。我们对这个系统的测光显示，这两个组件是不太明亮的比任何已知的亚星双星。结合一个新的集成光光谱（T9 p）和解决YJH波段光度从凯克允许我们执行光谱分解和分配T9和Y 0的组件类型。光谱中的许多不寻常的特征可以用高表面重力来解释：Y带峰加宽到蓝色; J带峰加宽到红色; H带峰轻微地向红色移动;红色的Y-J颜色。有趣的是，非常低的光度意味着T9主星出乎意料地冷（假设年龄为10 Gyr，则$T_{\rm eff}$ = 345 $\pm$ 45 K），使其比任何其他晚T矮星都要冷$\approx$ 100 K，并可与Y矮星相媲美。对于这种明显的差异，一个有趣的解释是，触发从T到Y光谱类型转变的J-和H-波段光谱特征高度依赖于重力。这一点在不久的将来可以通过轨道监测直接加以检验。我们约束的轨道周期为$\lesssim$ 10年相结合的组件（$\approx$ 12 $-$ 21 $M_{\rm Jup}$，1 $σ$在10 Gyr）与统计约束的半长轴（$\lesssim$ 1.3 AU）的进化模型为基础的质量估计。这样的周期比任何已知的T/Y转换双星都要短，这意味着WISEJ 0146 + 4234 AB可能会在未来几年内产生动力学质量。

英文摘要：

We have discovered that the brown dwarf WISEJ014656.66+423410.0 is a close binary (0.0875$\pm$0.0021 arcsec, 0.93$^{+0.12}_{-0.16}$ AU) from Keck laser guide star adaptive optics imaging. Our photometry for this system reveals that both components are less luminous than those in any known substellar binary. Combining a new integrated-light spectrum (T9p) and resolved YJH-band photometry from Keck allows us to perform spectral decomposition and assign component types of T9 and Y0. Many of the unusual features in the spectrum might be explained by high surface gravity: Y-band peak broadened to the blue; J-band peak broadened to the red; H-band peak shifted slightly to the red; and red Y-J colors. Interestingly, the very low component luminosities imply that the T9 primary is unexpectedly cold ($T_{\rm eff}$ = 345$\pm$45 K assuming an age of 10 Gyr), making it $\approx$100 K cooler than any other late-T dwarf and comparable to Y dwarfs. One intriguing explanation for this apparent discrepancy is that the J- and H-band spectral features that trigger the transition from T to Y spectral types are highly gravity-dependent. This can be tested directly in the very near future by orbit monitoring. We constrain the orbital period to be $\lesssim$10 yr by combining evolutionary model-based mass estimates for the components ($\approx$12$-$21 $M_{\rm Jup}$, 1$σ$ at 10 Gyr) with a statistical constraint on the semimajor axis ($\lesssim$1.3 AU). Such a period is shorter than any other known T/Y transition binary, meaning that WISEJ0146+4234AB will likely yield a dynamical mass within the next few years.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑