V1298 Tau with TESS: Updated Ephemerides, Radii, and Period Constraints from a Second Transit of V1298 Tau e
V1298 Tau with TESS: Updated Ephemerides, Radii, and Period Constraints from a Second Transit of V1298 Tau e
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DOI：
10.3847/2041-8213/ac4745
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发表时间：
2021-11
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影响因子：
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通讯作者：
A. D. Feinstein;T. David;B. Montet;D. Foreman-Mackey;J. Livingston;A. Mann
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作者：
A. D. Feinstein;T. David;B. Montet;D. Foreman-Mackey;J. Livingston;A. Mann
V1298 Tau是一颗年轻的（20-30兆当量）太阳质量的K恒星，拥有四颗凌日系外行星，大小在0.5到0.9兆当量之间。鉴于该系统的年轻，它提供了一个独特的机会来了解在同一恒星环境中不同距离的行星半径的演变。V1298 Tau最初是在6年前K2战役4期间被观测到的。现在，在NASA的凌日系外行星测量卫星（TESS）的扩展任务中，V1298 Tau被重新观测到。在这里，我们提出了来自TESS的V1298 Tau的新光度观测结果。我们使用TESS数据更新了V1298 Tau bcd的星历表，并将新观测到的半径与K2光曲线测量的半径进行了比较，发现V1298 Tau bcd在较红的TESS带通中在1-2σ水平上有较浅的凌日现象。我们怀疑半径的差异是由于恒星黑子交叉事件或附近暗淡恒星在V1298 Tau相同像素上的污染。此外，我们捕获了V1298 Tau e的第二次凌日，并提出了一种新的方法，从相隔几年的两次观测中得出行星周期的边缘后验概率。我们发现V1298 Tau e与V1298 Tau b的最高概率周期接近2:1的平均运动共振，如果得到证实，可能使V1298 Tau成为一个四行星共振链。V1298 Tau是几个正在进行和未来观测的目标。这些更新的星历表对于安排未来的凌日观测和解释未来的多普勒层析成像或透射光谱信号至关重要。
V1298 Tau is a young (20–30 Myr) solar-mass K star hosting four transiting exoplanets with sizes between 0.5 and 0.9 R J. Given the system’s youth, it provides a unique opportunity to understand the evolution of planetary radii at different separations in the same stellar environment. V1298 Tau was originally observed 6 yr ago during K2 Campaign 4. Now, V1298 Tau has been re-observed during the extended mission of NASA’s Transiting Exoplanet Survey Satellite (TESS). Here, we present new photometric observations of V1298 Tau from TESS. We use the TESS data to update the ephemerides for V1298 Tau bcde as well as compare newly observed radii to those measured from the K2 light curve, finding shallower transits for V1298 Tau bcd in the redder TESS bandpass at the 1–2σ level. We suspect the difference in radii is due to starspot crossing events or contamination from nearby faint stars on the same pixels as V1298 Tau. Additionally, we catch a second transit of V1298 Tau e and present a new method for deriving the marginalized posterior probability of a planet’s period from two transits observed years apart. We find the highest probability period for V1298 Tau e to be in a near 2:1 mean motion resonance with V1298 Tau b which, if confirmed, could make V1298 Tau bcde a four-planet resonant chain. V1298 Tau is the target of several ongoing and future observations. These updated ephemerides will be crucial for scheduling future transit observations and interpreting future Doppler tomographic or transmission spectroscopy signals.