11:00 〜 11:15
[PCG19-08] Revealing the Ultra-Hot Jupiterʼs Dayside Emission Spectrum Using Ground-Based Telescopes
キーワード：ウルトラホットジュピター、惑星大気、2次食
Some strongly irradiated gas giant planets called Ultra-Hot Jupiters(UHJ) exhibit thermal inversion in their dayside atmospheres (Changeat & Edwards et al. 2022). These temperature profiles are thought to result from stellar light absorbers in their atmospheres.
The primary candidates for the stellar light absorbers in extremely hot(>2500 K) environments are H- bound-free and free-free absorption. Due to the continuum opacities and the absence of other molecules, UHJ’s emission spectra are expected to resemble a blackbody-like emission(Mansfield et al. 2021) in <1.4 μm.
In this research, we investigated the wavelength dependence of KELT-9 b’s dayside emission. KELT-9 b holds the record as the hottest planet discovered to date (Gaudi et al. 2017), with a dayside temperature reaching 4600 K (Wong et al. 2021). HST/WFC3 observations in the infrared band have confirmed the presence of a thermal inversion in the dayside atmosphere of this planet (Changeat & Edwards 2021). The strong H- absorption signal was detected as expected (Jacobs et al. 2022). On the other hand, TiO/VO were also detected (Changeat & Edwards et al. 2021) despite the extremely high temperature environment, where molecules are difficult to survive.
We employed the 1.52 m telescope equipped with a multi-band imager known as MuSCAT2, and the 1 m telescope with a single-band imager named Sinistro for our research. Using these instruments, we observed secondary eclipses, which are the temporal dimming caused by the occultation of the planet by the host star.
In the analysis, we used the Batman, open-source code to model the secondary eclipse light curve. We also attempt Gaussian Process regression(GPR) for modeling the systematics noise.
As a result, the secondary eclipse signals were detected in r, i, z, and Y-band. The derived i-band eclipse depth indicates a much lower temperature than previous studies and contradicts the blackbody-like emission. This result likely indicate that not only H- opacity but also other opacity sources exist in the dayside atmosphere of KELT-9b.
In this presentation, we will introduce the details of observation and analysis, as well as discuss the potential optical absorbers present in the dayside atmosphere of KELT-9 b.
The primary candidates for the stellar light absorbers in extremely hot(>2500 K) environments are H- bound-free and free-free absorption. Due to the continuum opacities and the absence of other molecules, UHJ’s emission spectra are expected to resemble a blackbody-like emission(Mansfield et al. 2021) in <1.4 μm.
In this research, we investigated the wavelength dependence of KELT-9 b’s dayside emission. KELT-9 b holds the record as the hottest planet discovered to date (Gaudi et al. 2017), with a dayside temperature reaching 4600 K (Wong et al. 2021). HST/WFC3 observations in the infrared band have confirmed the presence of a thermal inversion in the dayside atmosphere of this planet (Changeat & Edwards 2021). The strong H- absorption signal was detected as expected (Jacobs et al. 2022). On the other hand, TiO/VO were also detected (Changeat & Edwards et al. 2021) despite the extremely high temperature environment, where molecules are difficult to survive.
We employed the 1.52 m telescope equipped with a multi-band imager known as MuSCAT2, and the 1 m telescope with a single-band imager named Sinistro for our research. Using these instruments, we observed secondary eclipses, which are the temporal dimming caused by the occultation of the planet by the host star.
In the analysis, we used the Batman, open-source code to model the secondary eclipse light curve. We also attempt Gaussian Process regression(GPR) for modeling the systematics noise.
As a result, the secondary eclipse signals were detected in r, i, z, and Y-band. The derived i-band eclipse depth indicates a much lower temperature than previous studies and contradicts the blackbody-like emission. This result likely indicate that not only H- opacity but also other opacity sources exist in the dayside atmosphere of KELT-9b.
In this presentation, we will introduce the details of observation and analysis, as well as discuss the potential optical absorbers present in the dayside atmosphere of KELT-9 b.