Theory suggests that the orbits of some close-in giant planets should decay due to tidal interactions with their host stars. To date, WASP-12b is the only hot Jupiter reported to have a decaying orbit, at a rate of 29$\pm$2 msec year$^{-1}$. We analyzed data from NASA's Transiting Exoplanet Survey Satellite (TESS) to verify that WASP-12b's orbit is indeed changing. We find that the TESS transit and occultation data are consistent with a decaying orbit with an updated period of 1.091420090$\pm$0.000000041 days and a decay rate of 32.53$\pm$1.62 msec year$^{-1}$. We find an orbital decay timescale of $\tau$ = P/$|\dot P|$ = 2.90$\pm$0.14 Myr. If the observed decay results from tidal dissipation, the modified tidal quality factor is Q'$_{\star}$ = 1.39$\pm$0.15 $\times 10^{5}$, which falls at the lower end of values derived for binary star systems and hot Jupiters. Our result highlights the power of space-based photometry for investigating the orbital evolution of short-period exoplanets.

中文翻译：

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热木星 WASP-12b 的衰变轨道：TESS 观测证实

理论表明，由于与宿主恒星的潮汐相互作用，一些靠近的巨行星的轨道应该会衰减。迄今为止，WASP-12b 是唯一据报道有衰变轨道的热木星，其衰减速度为每年 29$\pm$2 毫秒 $^{-1}$。我们分析了来自美国宇航局过境系外行星勘测卫星 (TESS) 的数据，以验证 WASP-12b 的轨道确实在发生变化。我们发现TESS凌日和掩星数据与衰减轨道一致，更新周期为1.091420090$\pm$0.000000041天，衰减率为32.53$\pm$1.62 msec year$^{-1}$。我们发现 $\tau$ = P/$|\dot P|$ = 2.90$\pm$0.14 Myr 的轨道衰减时间尺度。如果观测到的衰减是由潮汐耗散引起的，则修改后的潮汐质量因子为 Q'$_{\star}$ = 1.39$\pm$0.15 $\times 10^{5}$，它落在双星系统和热木星的值的下端。我们的结果突出了天基测光在研究短周期系外行星的轨道演化方面的力量。