A Caltech Library Service

Hat-P-20b-Hat-p-23b: Four Massive Transiting Extrasolar Planets

Bakos, G. Á. and Hartman, J. and Torres, G. and Latham, D. W. and Kovács, Géza and Noyes, R. W. and Fischer, D. A. and Johnson, J. A. and Marcy, G. W. and Howard, A. W. and Kipping, D. and Esquerdo, G. A. and Shporer, A. and Béky, B. and Buchhave, L. A. and Perumpilly, G. and Everett, M. and Sasselov, D. D. and Stefanik, R. P. and Lázár, J. and Papp, I. and Sári, P. (2011) Hat-P-20b-Hat-p-23b: Four Massive Transiting Extrasolar Planets. Astrophysical Journal, 742 (2). Art. No. 116. ISSN 0004-637X.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We report the discovery of four relatively massive (2-7 M J) transiting extrasolar planets. HAT-P-20b orbits the moderately bright V = 11.339 K3 dwarf star GSC 1910-00239 on a circular orbit, with a period P = 2.875317 ± 0.000004 days, transit epoch T_c = 2455080.92661 ± 0.00021 (BJD_(UTC)), and transit duration 0.0770 ± 0.0008 days. The host star has a mass of 0.76 ± 0.03 M_☉, radius of 0.69 ± 0.02 R_☉, effective temperature 4595 ± 80 K, and metallicity [Fe/H] = +0.35 ± 0.08. The planetary companion has a mass of 7.246 ± 0.187 M_J and a radius of 0.867 ± 0.033 R_J yielding a mean density of 13.78 ± 1.50 g cm^(–3). HAT-P-21b orbits the V = 11.685 G3 dwarf star GSC 3013-01229 on an eccentric (e = 0.228 ± 0.016) orbit, with a period P = 4.124481 ± 0.000007 days, transit epoch T_c = 2454996.41312 ± 0.00069, and transit duration 0.1530 ± 0.0027 days. The host star has a mass of 0.95 ± 0.04 M_☉, radius of 1.10 ± 0.08 R_☉, effective temperature 5588 ± 80 K, and metallicity [Fe/H] = +0.01 ± 0.08. The planetary companion has a mass of 4.063 ± 0.161 M_J and a radius of 1.024 ± 0.092 R_J yielding a mean density of 4.68^(+1.59)_(–0.99) g cm^(-3). HAT-P-21b is a borderline object between the pM and pL class planets, and the transits occur near apastron. HAT-P-22b orbits the bright V = 9.732 G5 dwarf star HD 233731 on a circular orbit, with a period P = 3.212220 ± 0.000009 days, transit epoch T_c = 2454930.22001 ± 0.00025, and transit duration 0.1196 ± 0.0014 days. The host star has a mass of 0.92 ± 0.03 M_☉, radius of 1.04 ± 0.04 R_☉, effective temperature 5302 ± 80 K, and metallicity [Fe/H] = +0.24 ± 0.08. The planet has a mass of 2.147 ± 0.061 M_J and a compact radius of 1.080 ± 0.058 R_J yielding a mean density of 2.11^(+0.40)_(–0.29) g cm^(–3). The host star also harbors an M-dwarf companion at a wide separation. Finally, HAT-P-23b orbits the V = 12.432 G0 dwarf star GSC 1632-01396 on a close to circular orbit, with a period P = 1.212884 ± 0.000002 days, transit epoch T_c = 2454852.26464 ± 0.00018, and transit duration 0.0908 ± 0.0007 days. The host star has a mass of 1.13 ± 0.04 M_☉, radius of 1.20 ± 0.07 R_☉, effective temperature 5905 ± 80 K, and metallicity [Fe/H] = +0.15 ± 0.04. The planetary companion has a mass of 2.090 ± 0.111 M_J and a radius of 1.368 ± 0.090 R_J yielding a mean density of 1.01 ± 0.18 g cm^(–3). HAT-P-23b is an inflated and massive hot Jupiter on a very short period orbit, and has one of the shortest characteristic infall times (7.5^(+2.9)_(–1.8) Myr) before it gets engulfed by the star.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bakos, G. Á.0000-0001-7204-6727
Torres, G.0000-0002-5286-0251
Latham, D. W.0000-0001-9911-7388
Fischer, D. A.0000-0003-2221-0861
Johnson, J. A.0000-0001-9808-7172
Marcy, G. W.0000-0002-2909-0113
Howard, A. W.0000-0001-8638-0320
Esquerdo, G. A.0000-0002-9789-5474
Shporer, A.0000-0002-1836-3120
Buchhave, L. A.0000-0003-1605-5666
Everett, M.0000-0002-0885-7215
Sasselov, D. D.0000-0001-7014-1771
Additional Information:© 2011 The American Astronomical Society. Received 2010 August 1; accepted 2011 August 15; published 2011 November 15. Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology. Keck time has been granted by NOAO and NASA. HATNet operations have been funded by NASA grants NNG04GN74G, NNX08AF23G, and SAO IR&D grants. Work of G.Á.B. was supported by the Postdoctoral Fellowship of the NSF Astronomy and Astrophysics Program (AST-0702843 and AST-0702821, respectively). G.T. acknowledges partial support from NASA grant NNX09AF59G. We acknowledge partial support also from the Kepler Mission under NASA Cooperative Agreement NCC2-1390 (D.W.L., PI). G.K. thanks the Hungarian Scientific Research Foundation (OTKA) for support through grant K-81373. This research has made use of Keck telescope time granted through NOAO and NASA, and uses observations obtained with facilities of the Las Cumbres Observatory Global Telescope. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Smithsonian Astrophysical ObservatoryUNSPECIFIED
NSF Astronomy and Astrophysics FellowshipAST-0702843
NSF Astronomy and Astrophysics FellowshipAST-0702821
Hungarian Scientific Research Fund (OTKA)K-81373
National Optical Astronomy Observatory (NOAO)UNSPECIFIED
Subject Keywords:stars: individual (HAT-P-20, HAT-P-21, HAT-P-22, HAT-P-23); techniques: photometric; techniques: spectroscopic
Issue or Number:2
Record Number:CaltechAUTHORS:20111223-113730703
Persistent URL:
Official Citation:HAT-P-20b–HAT-P-23b: Four Massive Transiting Extrasolar Planets G. Á. Bakos et al. 2011 ApJ 742 116
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:28592
Deposited By: Ruth Sustaita
Deposited On:03 Jan 2012 16:15
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page