摘要：In this paper we present MASCARA-2 b, a hot Jupiter transiting themV= 7.6 A2 star HD 185603. Since early 2015, MASCARA has taken more than 1.6 million flux measurements of the star, corresponding to a total of almost 3000 h of observations, revealing a periodic dimming in the flux with a depth of 1.3%. Photometric follow-up observations were performed with the NITES and IAC80 telescopes and spectroscopic measurements were obtained with the Hertzsprung SONG telescope. We find MASCARA-2 b orbits HD 185603 with a period of 3.4741119-0.000006+0.000005at a distance of 0.057 ± 0.006 au, has a radius of 1.83 ± 0.07 RJand place a 99% upper limit on the mass of <17 MJ. HD 185603 is a rapidly rotating early-type star with an effective temperature of 8980-130+90K and a mass and radius of 1.89-0.05+0.06M⊙, 1.60 ± 0.06R⊙, respectively. Contrary to most other hot Jupiters transiting early-type stars, the projected planet orbital axis and stellar spin axis are found to be aligned withλ= 0.6 ± 4°. The brightness of the host star and the high equilibrium temperature, 2260 ± 50 K, of MASCARA-2 b make it a suitable target for atmospheric studies from the ground and space. Of particular interest is the detection of TiO, which has recently been detected in the similarly hot planets WASP-33 b and WASP-19 b.
关键词：Key wordsenplanetary systemsstars: individual: MASCARA-2 (HD 185603, HIP 96618)
