论文标题
用HST窄场天体统计扩展Gaia Dr2。 ii。精炼WISE J163940.83-684738.6的方法
Extending Gaia DR2 with HST narrow-field astrometry. II. Refining the method on WISE J163940.83-684738.6
论文作者
论文摘要
在本系列的第二篇论文中，我们完善了将高精度哈勃空间望远镜天文统计与高精度GAIA DR2绝对参考系统联系起来的方法，以克服用窄场相机的相对星形统计的局限性。我们这里的测试案例是Y Brown Dwarf明智的J163940.83-684738.6，在不同时期内观察到，分布在6年的时间基线上，与先前的确定相比，我们得出的田间摄像头3的Infra-RED频道显着改善了Astormotric参数：（ （577.21 +/- 0.24Mas/yr，-3108.39 +/- 0.27Mas/yr，210.4 +/- 1.8Mas）。特别是，我们衍生的绝对视差对应于微弱的超级矮人的4.75 +/- 0.05pc。
In the second paper of this series we perfected our method of linking high precision Hubble Space Telescope astrometry to the high-accuracy Gaia DR2 absolute reference system to overcome the limitations of relative astrometry with narrow-field cameras. Our test case here is the Y brown dwarf WISE J163940.83-684738.6, observed at different epochs spread over a 6-yr time baseline with the Infra-Red channel of the Wide Field Camera 3. We derived significantly improved astrometric parameters compared to previous determinations, finding: (mu_RAcosDc,mu_DC,parallax) = (577.21+/-0.24mas/yr,-3108.39+/-0.27mas/yr,210.4+/-1.8mas). In particular, our derived absolute parallax corresponds to a distance of 4.75+/-0.05pc for the faint ultracool dwarf.
