NGTS-2b: an inflated hot-Jupiter transiting a bright F-dwarf
Smalley, Barry; Wheatley, Peter J.; Bayliss, Daniel; Raddi, Roberto; Moyano, Maximiliano; Günther, Maximilian N.; Cabrera, Juan; Csizmadia, Szilard; Eigmüller, Philipp; Erikson, Anders; Rauer, Heike; Casewell, Sarah L.; Goad, Michael R.; Armstrong, David J.; Burleigh, Matthew R.; Gillen, Edward; Jenkins, James S.; McCormac, James; Udry, Stéphane; West, Richard G.; Smith, Alexis M. S.; Gänsicke, Boris T.; Queloz, Didier; Watson, Christopher A.; Chazelas, Bruno; Lambert, Gregory; Bouchy, François; Chaushev, Alexander; Grange, Andrew; Hodgkin, Simon T.; Louden, Tom; Metrailler, Lionel; Nielsen, Louise D.; Poppenhaeger, Katja; Raynard, Liam; Soto, Maritza; Pollacco, Don; Thompson, Andrew P. G.; Briegal, Joshua T.; Turner, Oliver; Hooton, Matthew J.; Cooke, Benjamin F.; Alexander, Richard; Walker, Simon R.; Read, Andrew M.
United Kingdom, Switzerland, Chile, Germany
Abstract
We report the discovery of NGTS-2b, an inflated hot-Jupiter transiting a bright F5V star (2MASS J14202949 - 3112074; Teff = 6478^{+94}_{-89} K), discovered as part of the Next Generation Transit Survey (NGTS). The planet is in a P = 4.51 d orbit with mass 0.74^{+0.13}_{-0.12}MJ, radius 1.595^{+0.047}_{-0.045}RJ, and density 0.226^{+0.040}_{-0.038} g cm-3; therefore one of the lowest density exoplanets currently known. With a relatively deep 1.0{{ per cent}} transit around a bright V = 10.96 host star, NGTS-2b is a prime target for probing giant planet composition via atmospheric transmission spectroscopy. The rapid rotation (v sin i = 15.2 ± 0.8 km s-1) also makes this system an excellent candidate for Rossiter-McLaughlin follow-up observations, to measure the sky-projected stellar obliquity. NGTS-2b was confirmed without the need for follow-up photometry, due to the high precision of the NGTS photometry.