HAT-P-26b: A LOW-DENSITY NEPTUNE-MASS PLANET TRANSITING A K STAR

被引：91

作者：

Hartman, J. D. ^{[1
]}

Bakos, G. A. ^{[1
]}

Kipping, D. M. ^{[1
,2
]}

Torres, G. ^{[1
]}

Kovacs, G. ^{[3
]}

Noyes, R. W. ^{[1
]}

Latham, D. W. ^{[1
]}

Howard, A. W. ^{[4
]}

Fischer, D. A. ^{[5
]}

Johnson, J. A. ^{[6
]}

Marcy, G. W. ^{[4
]}

Isaacson, H. ^{[4
]}

Quinn, S. N. ^{[1
]}

Buchhave, L. A. ^{[1
,7
]}

Beky, B. ^{[1
]}

Sasselov, D. D. ^{[1
]}

Stefanik, R. P. ^{[1
]}

Esquerdo, G. A. ^{[1
]}

Everett, M. ^{[1
]}

Perumpilly, G. ^{[1
,8
]}

Lazar, J. ^{[9
]}

Papp, I. ^{[9
]}

Sari, P. ^{[9
]}

机构：

[1] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[2] UCL, Dept Phys & Astron, London, England

[3] Konkoly Observ Budapest, Budapest, Hungary

[4] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA

[5] Yale Univ, Dept Astron, New Haven, CT 06511 USA

[6] CALTECH, Dept Astrophys, Pasadena, CA 91125 USA

[7] Univ Copenhagen, Niels Bohr Inst, DK-2100 Copenhagen, Denmark

[8] Univ S Dakota, Dept Phys, Vermillion, SD 57069 USA

[9] Hungarian Astron Assoc, Budapest, Hungary

来源：

ASTROPHYSICAL JOURNAL | 2011年 / 728卷 / 02期

关键词：

planetary systems; stars:; individual; (HAT-P-26; GSC; 0320-01027); techniques: photometric; techniques: spectroscopic; SUPER-EARTH; ECLIPSING BINARIES; ATMOSPHERIC LOSS; BLEND SCENARIOS; OPEN CLUSTERS; HOT-JUPITERS; LIGHT CURVES; STELLAR; EVOLUTION; ALGORITHM;

D O I：

10.1088/0004-637X/728/2/138

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We report the discovery of HAT-P-26b, a transiting extrasolar planet orbiting the moderately bright V = 11.744 K1 dwarf star GSC 0320-01027, with a period P = 4.234516 +/- 0.000015 days, transit epoch T-c = 2455304.65122 +/- 0.00035 ( BJD; Barycentric Julian dates throughout the paper are calculated from Coordinated Universal Time (UTC)), and transit duration 0.1023 +/- 0.0010 days. The host star has a mass of 0.82 +/- 0.03 M-circle dot, radius of 0.79(0.04)(+0.10) R-circle dot, effective temperature 5079 +/- 88 K, and metallicity [Fe/H] = -0.04 +/- 0.08. The planetary companion has a mass of 0.059 +/- 0.007 M-J, and radius of 0.565(-0.032)(+0.072) R-J yielding a mean density of 0.40 +/- 0.10 g cm(-3). HAT-P-26b is the fourth Neptune-mass transiting planet discovered to date. It has a mass that is comparable to those of Neptune and Uranus, and slightly smaller than those of the other transiting Super-Neptunes, but a radius that is similar to 65% larger than those of Neptune and Uranus, and also larger than those of the other transiting Super-Neptunes. HAT-P-26b is consistent with theoretical models of an irradiated Neptune-mass planet with a 10 M-circle plus heavy element core that comprises greater than or similar to 50% of its mass with the remainder contained in a significant hydrogen-helium envelope, though the exact composition is uncertain as there are significant differences between various theoretical models at the Neptune-mass regime. The equatorial declination of the star makes it easily accessible to both Northern and Southern ground-based facilities for follow-up observations.

引用

页数：14

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