HAT-P-11b: A SUPER-NEPTUNE PLANET TRANSITING A BRIGHT K STAR IN THE KEPLER FIELD

By Gáspár Á. Bakos, G. Torres, A. Pál, Joel D. Hartman, G'eza Kov'acs, R. W. Noyes, D. Latham, D. Sasselov, B. SipHocz, G. Esquerdo and 24 more. 2009

274 citations recorded by the source corpus.

We report on the discovery of HAT-P-11b, the smallest radius transiting extrasolar planet (TEP) discovered from the ground, and the first hot Neptune discovered to date by transit searches. HAT-P-11b orbits the bright (V = 9.587) and metal rich ([Fe/H] = +0.31 ± 0.05) K4 dwarf star GSC 03561–02092 with P = 4.8878162 ± 0.0000071 days and produces a transit signal with depth of 4.2 mmag, the shallowest found by transit searches that is due to a confirmed planet. We present a global analysis of the available photometric and radial velocity (RV) data that result in stellar and planetary parameters, with simultaneous treatment of systematic variations. The planet, like its near-twin GJ 436b, is somewhat larger than Neptune (17 M⊕, 3.8 R⊕) both in mass Mp = 0.081 ± 0.009 MJ(25.8 ± 2.9 M⊕) and radius Rp = 0.422 ± 0.014 RJ(4.73 ± 0.16 R⊕). HAT-P-11b orbits in an eccentric orbit with e = 0.198 ± 0.046 and ω = 355.°2 ± 17.°3, causing a reflex motion of its parent star with amplitude 11.6 ± 1.2 m s−1, a challenging detection due to the high level of chromospheric activity of the parent star. Our ephemeris for the transit events is Tc = 2454605.89132 ± 0.00032 (BJD), with duration 0.0957 ± 0.0012 days, and secondary eclipse epoch of 2454608.96 ± 0.15 days (BJD). The basic stellar parameters of the host star are M⋆ = 0.809+0.020−0.027 M☉, R⋆ = 0.752 ± 0.021 R☉, and Teff⋆ = 4780 ± 50 K. Importantly, HAT-P-11 will lie on one of the detectors of the forthcoming Kepler mission; this should make possible fruitful investigations of the detailed physical characteristic of both the planet and its parent star at unprecedented precision. We discuss an interesting constraint on the eccentricity of the system by the transit light curve and stellar parameters. This will be particularly useful for eccentric TEPs with low-amplitude RV variations in Kepler's field. We also present a blend analysis, that for the first time treats the case of a blended transiting hot Jupiter mimicking a transiting hot Neptune, and proves that HAT-P-11b is not such a blend.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/84d672aed9ee113f2f1661f3b1aefe530853ad3a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

AN ANCIENT EXTRASOLAR SYSTEM WITH FIVE SUB-EARTH-SIZE PLANETS (2015, background): “…a distance d=35.7± 1.1 pc in the constellation Lyra, commensurate with the distances to Kepler-3 (a bright K dwarf with a transiting hot-Neptune at d= 36.4 ± 1.3 pc; Bakos et al. 2010) and Kepler-42 (an M dwarf with three transiting sub-Earth-size planets at d=38.7± 6.3 pc; Muirhead et al. 2012).”
A FRAMEWORK FOR QUANTIFYING THE DEGENERACIES OF EXOPLANET INTERIOR COMPOSITIONS (2009, methodology): “At ρp = 1.33 ± 0.20 g cm −3 (Bakos et al. 2010), HAT P11b is less dense than GJ 436b (ρp = 1.69 +0.14 −0.12 g cm −3 Torres et al. 2008).”
Kepler Planet Masses and Eccentricities from TTV Analysis (2016, background): “Many sub-Jovian transiting planets have had their masses measured through RV follow-up (e.g., Bakos et al. 2010; Bordé et al. 2010; Borucki et al. 2010; Hartman et al. 2011; Gautier et al. 2012; Gilliland et al. 2013; Pepe et al. 2013; Alonso et al. 2014; Barros et al. 2014; Dumusque et al. 2014;…”
ORBITAL PHASE VARIATIONS OF THE ECCENTRIC GIANT PLANET HAT-P-2b (2013, methodology): “Our use of β̃ is similar to the incorporation of parameters for the PSF width and elongation in the correction of systematic variations as discussed in Bakos et al. (2010) for HATnet data.”
FRIENDS OF HOT JUPITERS. I. A RADIAL VELOCITY SEARCH FOR MASSIVE, LONG-PERIOD COMPANIONS TO CLOSE-IN GAS GIANT PLANETS (2013, unknown): “…secondary eclipse times. e REFERENCES FOR ORBITAL INCLINATIONS AND SPIN-ORBIT ANGLES - (1) Torres et al. (2008); (2) Carter et al. (2009); (3) Albrecht et al. (2012b); (4) Pál et al. (2010); (5) Winn et al. (2011); (6) Winn et al. (2009b); (7) Simpson et al. (2011); (8) Moutou et al. (2011); (9)…”
STARSPOTS, SPIN–ORBIT MISALIGNMENT, AND ACTIVE LATITUDES IN THE HAT-P-11 EXOPLANETARY SYSTEM (2011, methodology): “This is consistent with the earlier estimate of 29.2 days by Bakos et al. (2010) from ground-based photometry. identified “by hand” and assigned zero weight in a subsequent fit to the data.”
Homogeneous studies of transiting extrasolar planets – IV. Thirty systems with space-based light curves (2011, methodology): “TheKepler data don’t agree exactly with previous orbital ephemerides of the system so theT0 from Bakos et al. (2010) was included as a constraint following the approach of Southworth et al. (2007a).”
Detection of a transit of the super-Earth 55 Cancri e with warm Spitzer (2011, background): “Among all the low-mass transiting exoplanets detected so far, only GJ 1214b and GJ 436b, and to a lesser extent HAT-P-11b and HAT-P-26 b, orbit around stars small enough and bright enough in the infrared to make possible a thorough atmospheric characterization with existing or future facilities like”
PLANET OCCURRENCE WITHIN 0.25 AU OF SOLAR-TYPE STARS FROM KEPLER (2011, background): “…(17 M⊕) and densities less than 2 g cm−3: Kepler-4b (Borucki et al. 2010), Gl 436b (Maness et al. 2007; Gillon et al. 2007; Torres et al. 2008), HAT-P-11b (Bakos et al. 2010), HAT-P-26b (Hartman et al. 2011), Corot-8b (Bordé et al. 2010), and HD 149026b (Sato et al. 2005; Torres et al. 2008).”