Henning, TMancini, LSarkis, PBakos, G AHartman, J DBayliss, DanielBento, JoaoBhatti, WaqasBrahm, RCiceri, SCsubry, Zde Val-Borro, MZhou, George2021-11-030004-6256http://hdl.handle.net/1885/251542We report the discovery of four close-in transiting exoplanets (HATS-50b through HATS-53b), discovered using the HATSouth three-continent network of homogeneous and automated telescopes. These new exoplanets belong to the class of hot Jupiters and orbit G-type dwarf stars, with brightness in the range V = 12.5-14.0 mag. While HATS-53 has many physical characteristics similar to the Sun, the other three stars appear to be metal-rich ([Fe H] = 0.2-0.3), larger, and more massive. Three of the new exoplanets, namely HATS-50b, HATS-51b, and HATS-53b, have low density (HATS-50b: 0.39 ± 0.10 MJ, 1.130 ± 0.075 RJ; HATS-51b: 0.768 ± 0.045 MJ, 1.41 ± 0.19 RJ; HATS-53b: 0.595 ± 0.089 MJ, 1.340 ± 0.056 RJ) and similar orbital periods (3.8297 days, 3.3489 days, 3.8538 days, respectively). Instead, HATS-52b is more dense (mass 2.24 ± 0.15 MJ and radius 1.382 ± 0.086 RJ) and has a shorter orbital period (1.3667 days). It also receives an intensive radiation from its parent star and, consequently, presents a high equilibrium temperature (Teq = 1834 ± 73 K). HATS-50 shows a marginal additional transit feature consistent with an ultra-short-period hot super Neptune (upper mass limit 0.16 MJ), which will be able to be confirmed with TESS photometry.Development of the HATSouth project was funded by NSF MRI grant NSF/AST-0723074, operations have been supported by NASA grants NNX09AB29G, NNX12AH91H, and NNX17AB61G, and follow-up observations receive partial support from grant NSF/AST-1108686. J.H. acknowledges support from NASA grant NNX14AE87G. A.J. acknowledges support from FONDECYT project 1171208, BASAL CATA PFB-06, and project IC120009 “Millennium Institute of Astrophysics (MAS)” of the Millennium Science Initiative, Chilean Ministry of Economy. N.E. is supported by CONICYT-PCHA/ Doctorado Nacional. R.B. and N.E. acknowledge support from project IC120009 “Millennium Institute of Astrophysics (MAS)” of the Millennium Science Initiative, Chilean Ministry of Economy. V.S. acknowledges support form BASAL CATA PFB-06. A.V. is supported by the NSF Graduate Research Fellowship, grant No. DGE 1144152. This work also uses observations obtained with facilities of the Las Cumbres Observatory Global Telescope (LCOGT). This work is based on observations collected with HARPS at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 095.C-0367. This work has made use of data from the European Space Agency (ESA) mission Gaia (https:// www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa. int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. We acknowledge the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund, and the SIMBAD database, operated at CDS, Strasbourg, France. Operations at the MPG 2.2 m Telescope are jointly performed by the Max Planck Gesellschaft and the European Southern Observatory in La Silla. We thank the MPG 2.2 m telescope support team for their technical assistance during observations.” This work is based in part on observations carried out with the Keck I telescope at Mauna Kea Observatory in Hawaii. Time on this facility was awarded through the Australian community access. Australian community access to the Keck Observatory was supported through the Australian Government’s National Collaborative Research Infrastructure Strategy, via the Department of Education and Training, and an Australian Government astronomy research infrastructure grant, via the Department of Industry and Science.application/pdfen-AU© 2018. The American Astronomical Societystars: individual (HATS-50, HATS-51, HATS-52, HATS-53)techniques: photometric201810.3847/1538-3881/aaa2542020-11-23