In this paper we present MASCARA-2 b , a hot Jupiter transiting the m _ { V } = 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 hours 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 3.474119 ^ { +0.000005 } _ { -0.000006 } ~ { } days at a distance of 0.057 \pm 0.006 ~ { } AU , has a radius of 1.83 \pm 0.07 ~ { } R _ { J } and place a 99 \% upper limit on the mass of < 17 ~ { } M _ { J } .
HD 185603 is a rapidly rotating early-type star with an effective temperature of 8980 ^ { +90 } _ { -130 } K and a mass and radius of 1.89 ^ { +0.06 } _ { -0.05 } M _ { \odot } , 1.60 \pm 0.06 R _ { \odot } , 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 with \lambda = 0.6 \pm 4 \degr .
The brightness of the host star and the high equilibrium temperature , 2260 \pm 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 .