http://arxiv.org/abs/1906.03276
We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V=8.3 mag, K=7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a $T_{\rm eff}$ =$6508\pm49$ K, a mass of $M_{}$ = $1.461^{+0.056}{-0.060}$ $M{\odot}$, radius of $R_{}$ = $1.506\pm0.022$ $R_{\odot}$, and an age of $0.77^{+0.61}{-0.42}$ Gyr. Its planetary companion (KELT-24 b) has a radius of $R{\rm P}$ = $1.272^{+0.021}{-0.022}$ $R{\rm J}$, a mass of $M_{\rm P}$ = $5.18^{+0.21}{-0.22}$ $M{\rm J}$, and from Doppler tomographic observations, we find that the planet’s orbit is well-aligned to its host star’s projected spin axis ($\lambda$ = $2.6^{+5.1}_{-3.6}$). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.
J. Rodriguez, J. Eastman, G. Zhou, et. al.
Tue, 11 Jun 19
1/60
Comments: 18 pages, 10 Figures, 6 Tables, Submitted to the AAS Journals
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