论文标题
光谱二进制棕色矮人的天体轨道i：大型T矮人的伴侣2m1059 $ - $ 21和2M0805 $+$+$ 48
Astrometric orbits of spectral binary brown dwarfs I: Massive T dwarf companions to 2M1059$-$21 and 2M0805$+$48
论文作者
论文摘要
近红外光谱调查发现了由低质量恒星和棕色矮人组成的短期，混合光谱二进制的人群。这些系统可以通过天文监测来适应轨道的确定和单个质量测量。在这里，我们提出了多年活动的第一个结果，旨在使用Gemini-South和Gemini-North GMOS Imagers获得光谱二进制的高精度绝对天体。我们测量了两个系统的完整天文轨道：2M0805 $+$+$ 48和2M1059 $ - $ 21。我们的2M0805 $+$ 48的天体轨道与先前确定的2年径向速度轨道一致，我们发现其T5.5伴侣的质量为$ 66^{+5} _ { - 14} M_ \ Mathrm {Jup} $。对于2M1059 $ - $ 21，我们找到了1。9年的轨道周期，质量为$ 67^{+4} _ { - 5} m_ \ Mathrm {Jup} $，用于其T3.5伴侣。我们证明，可以使用GMOS成像仪获得亚米利亚克的绝对天体，这是确认和表征Ultracool二进制系统的有效途径。
Near-infrared spectroscopic surveys have uncovered a population of short-period, blended-light spectral binaries composed of low-mass stars and brown dwarfs. These systems are amenable to orbit determination and individual mass measurements via astrometric monitoring. Here we present first results of a multi-year campaign to obtain high-precision absolute astrometry for spectral binaries using the Gemini-South and Gemini-North GMOS imagers. We measure the complete astrometric orbits for two systems: 2M0805$+$48 and 2M1059$-$21. Our astrometric orbit of 2M0805$+$48 is consistent with its 2-year radial velocity orbit determined previously and we find a mass of $66^{+5}_{-14} M_\mathrm{Jup}$ for its T5.5 companion. For 2M1059$-$21 we find a 1.9 year orbital period and a mass of $67^{+4}_{-5} M_\mathrm{Jup}$ for its T3.5 companion. We demonstrate that sub-milliarcsecond absolute astrometry can be obtained with both GMOS imagers and that this is an efficient avenue for confirming and characterising ultracool binary systems.
