南极洲ASTEP 400望远镜观测到的WASP-19 b的次日食
The secondary eclipses of WASP-19b as seen by the ASTEP 400 telescope from Antarctica
摘要：
ASTEP（Antarctica Search for Transiting ExoPlanets）计划最初旨在探测南极洲Dome C的质量，以便通过测光发现和表征系外行星。在40厘米ASTEP 400望远镜运行的第一年（2010年冬季），我们瞄准了已知的凌日行星WASP-19 b，以试图在可见光中探测其二次凌日。这是由于分箱数据具有优异的亚毫米级精度。WASP-19系统在2010年5月的24个夜晚被观测到。由星点引起的光度变化水平约为1.8%（峰-峰），与2007年的SuperWASP数据（1.4%）一致，大于2008年（0.07%）。我们发现WASP-19的旋转周期为10.7 +/- 0.5天，与SuperWASP测定的10.5 +/- 0.2天一致。理论模型表明，只有当恒星中的潮汐耗散较弱时，即潮汐耗散因子Q 'star> 3.10 ^[7]，才能解释这一现象。另外，我们发现了深度为390 +/- 190 ppm的二次日食的证据，具有2.0 sigma意义，与圆形轨道一致的相位和3%的假阳性概率。给定观测的波长范围（420至950 nm），二次凌日深度转换为2690（-220/+150）K的昼侧亮度温度，与z'和K波段的测量结果一致。在可见光中观察到的昼侧发射可能是由于极热的昼侧的热发射，几乎没有热量重新分配到夜侧，或者是由于恒星光的直接反射，最大几何反射率Ag=0.27 +/- 0.13。我们还报告了一个低频振荡以及在行星轨道周期的相位，但与下限振幅，不能单独归因于行星相位，并可能与残留的光变曲线趋势污染。
英文摘要：
The ASTEP (Antarctica Search for Transiting ExoPlanets) program was originally aimed at probing the quality of the Dome C, Antarctica for the discovery and characterization of exoplanets by photometry. In the first year of operation of the 40 cm ASTEP 400 telescope (austral winter 2010), we targeted the known transiting planet WASP-19b in order to try to detect its secondary transits in the visible. This is made possible by the excellent sub-millimagnitude precision of the binned data. The WASP-19 system was observed during 24 nights in May 2010. The photometric variability level due to starspots is about 1.8% (peak-to-peak), in line with the SuperWASP data from 2007 (1.4%) and larger than in 2008 (0.07%). We find a rotation period of WASP-19 of 10.7 +/- 0.5 days, in agreement with the SuperWASP determination of 10.5 +/- 0.2 days. Theoretical models show that this can only be explained if tidal dissipation in the star is weak, i.e. the tidal dissipation factor Q'star > 3.10^7. Separately, we find evidence for a secondary eclipse of depth 390 +/- 190 ppm with a 2.0 sigma significance, a phase consistent with a circular orbit and a 3% false positive probability. Given the wavelength range of the observations (420 to 950 nm), the secondary transit depth translates into a day side brightness temperature of 2690(-220/+150) K, in line with measurements in the z' and K bands. The day side emission observed in the visible could be due either to thermal emission of an extremely hot day side with very little redistribution of heat to the night side, or to direct reflection of stellar light with a maximum geometrical albedo Ag=0.27 +/- 0.13. We also report a low-frequency oscillation well in phase at the planet orbital period, but with a lower-limit amplitude that could not be attributed to the planet phase alone, and possibly contaminated with residual lightcurve trends.
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。
