MULTI-COLOR TRANSIT PHOTOMETRY OF GJ 1214b THROUGH<i>BJHK</i><sub>s</sub>BANDS AND A LONG-TERM MONITORING OF THE STELLAR VARIABILITY OF GJ 1214

Narita, Norio; Fukui, A.; Ikoma, Masahiro; Hori, Yasunori; Kurosaki, Kunihiko; Kawashima, Yui; Nagayama, Takahiro; Onitsuka, Masahiro; Sukom, Amnart; Nakajima, Yasushi; Tamura, Motohide; Kuroda, D.; Yanagisawa, K.; Hirano, Teruyuki; Kawauchi, Kiyoe; Kuzuhara, Masayuki; Ohnuki, Hiroshi; Suenaga, Takuya; Takahashi, Yasuhiro; Izumiura, Hideyuki; Kawai, N.; Yoshida, Michitoshi

doi:10.1088/0004-637x/773/2/144

Cited by 67 publications

(70 citation statements)

References 39 publications

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“…Since its discovery, many groups have published measurements of GJ1214bʼs transmission spectrum in the optical and nearinfrared (Bean et al 2010Croll et al 2011;Crossfield et al 2011;Désert et al 2011;Berta et al 2012;de Mooij et al 2012de Mooij et al , 2013Murgas et al 2012;Colón & Gaidos 2013;Fraine et al 2013;Narita et al 2013;Teske et al 2013;Cáceres et al 2014;Gillon et al 2014;Kreidberg et al 2014;Wilson et al 2014;Nascimbeni et al 2015). A total of 58 measurements have been published for bandpasses with central wavelengths shorter than 9260Å, the longest wavelength in our Magellan/ IMACS spectrum.…”

Section: Previous Measurementsmentioning

confidence: 99%

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

Rackham

Espinoza

Apai

et al. 2017

ApJ

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GJ1214b is the most studied sub-Neptune exoplanet to date. Recent measurements have shown its near-infrared transmission spectrum to be flat, pointing to a high-altitude opacity source in the exoplanetʼs atmosphere, either equilibrium condensate clouds or photochemical hazes. Many photometric observations have been reported in the optical by different groups, though simultaneous measurements spanning the entire optical regime are lacking. We present an optical transmission spectrum (4500-9260Å) of GJ1214b in 14 bins, measured with Magellan/IMACS repeatedly over three transits. We measure a mean planet-to-star radius ratio of ( ) in the spectral bins. The optical transit depths are shallower on average than observed in the near-infrared. We present a model for jointly incorporating the effects of a composite photosphere and atmospheric transmission through the exoplanetʼs limb (the CPAT model), and use it to examine the cases of absorber and temperature heterogeneities in the stellar photosphere. We find the optical and near-infrared measurements are best explained by the combination of (1) photochemical haze in the exoplanetary atmosphere with a mode particle size r=0.1μm and haze-forming efficiency = f 10% haze and (2) faculae in the unocculted stellar disk with a temperature contrast D = -+ T 354 46 46 K, assuming 3.2% surface coverage. The CPAT model can be used to assess potential contributions of heterogeneous stellar photospheres to observations of exoplanet transmission spectra, which will be important for searches for spectral features in the optical.

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Section: Previous Measurementsmentioning

confidence: 99%

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

Rackham

Espinoza

Apai

et al. 2017

ApJ

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“…We started the observation at 20:50 UT and continued it until 24:03 UT (the airmass changed from 1.54 to 1.10), covering the expected duration of a transit. During the SIRIUS observation, we employed the position-locking software to fix the centroid of the stellar images within a few pixels from the initial position (Narita et al 2013a(Narita et al , 2013b.…”

Section: K2 Photometrymentioning

confidence: 99%

THEK2-ESPRINT PROJECT III: A CLOSE-IN SUPER-EARTH AROUND A METAL-RICH MID-M DWARF

Hirano

Fukui

Mann

et al. 2016

ApJ

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We validate a R R 2.32 0.24 p =  Å planet on a close-in orbit (P=2.260455±0.000041 days) around K2-28 (EPIC206318379), a metal-rich M4-type dwarf in the Campaign 3 field of the K2 mission. Our follow-up observations included multi-band transit observations from the optical to the near-infrared, low-resolution spectroscopy, and high-resolution adaptive optics (AO) imaging. We perform a global fit to all of the observed transits using a Gaussian process-based method and show that the transit depths in all of the passbands adopted for the ground-based transit follow-ups (r z J H K , , , ,¢ ) are within ∼2σ of the K2 value. Based on a model of the background stellar population and the absence of nearby sources in our AO imaging, we estimate the probability that a background eclipsing binary could cause a false positive to be <2×10 −5 . We also show that K2-28 cannot have a physically associated companion of stellar type later than M4, based on the measurement of almost identical transit depths in multiple passbands. There is a low probability for an M4 dwarf companion ( 0.072 0.04 0.02 » -+), but even if this were the case, the size of K2-28b falls within the planetary regime. K2-28b has the same radius (within 1σ) and experiences irradiation from its host star similar to the well-studied GJ1214b. Given the relative brightness of K2-28 in the near-infrared (m 14.85 Kep = mag and m H =11.03 mag) and relatively deep transit (0.6%-0.7%), a comparison between the atmospheric properties of these two planets with future observations would be especially interesting.

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“…Simultaneous multiband observations of planetary transits have been obtained for several TEP systems using the instruments BUSCA (Southworth et al 2012b;Mancini et al 2013c), GROND (de Mooij et al 2012;Bayliss et al 2013;Mancini et al 2013a,b;Mohler-Fischer et al 2013;Nikolov et al 2013;Penev et al 2013;Southworth et al 2013), ULTRACAM (Bento et al 2013;Copperwheat et al 2013) and SIRIUS (Narita et al 2013). Table 1.…”

Section: Multiband Observations Of Planetary Transitsmentioning

confidence: 99%

Erratum: Physical properties, star-spot activity, orbital obliquity and transmission spectrum of the Qatar-2 planetary system from multicolour photometry

Mancini

Southworth

Ciceri

et al. 2016

Mon. Not. R. Astron. Soc.

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We present 17 high-precision light curves of five transits of the planet Qatar-2 b, obtained from four defocused 2 m-class telescopes. Three of the transits were observed simultaneously in the Sloan g r i z passbands using the seven-beam Gamma Ray Burst Optical and Near-Infrared Detector imager on the MPG/ESO 2.2-m telescope. A fourth was observed simultaneously in Gunn grz using the Centro Astronómico Hispano Alemán 2.2-m telescope with Bonn University Simultaneous Camera, and in r using the Cassini 1.52-m telescope. Every light curve shows small anomalies due to the passage of the planetary shadow over a cool spot on the surface of the host star. We fit the light curves with the PRISM+GEMC model to obtain the photometric parameters of the system and the position, size and contrast of each spot. We use these photometric parameters and published spectroscopic measurements to obtain the physical properties of the system to high precision, finding a larger radius and lower density for both star and planet than previously thought. By tracking the change in position of one star-spot between two transit observations, we measure the orbital obliquity of Qatar-2 b to be λ = 4.• 3 ± 4.• 5, strongly indicating an alignment of the stellar spin with the orbit of the planet. We calculate the rotation period and velocity of the cool host star to be 11.5 ± 0.2 d and 3.28 ± 0.04 km s −1 at a colatitude of 74 • . We assemble the planet's transmission spectrum over the 386-976 nm wavelength range and search for variations of the measured radius of Qatar-2 b as a function of wavelength. Our analysis highlights a possible H 2 /He Rayleigh scattering in the blue.

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MULTI-COLOR TRANSIT PHOTOMETRY OF GJ 1214b THROUGHBJHK_sBANDS AND A LONG-TERM MONITORING OF THE STELLAR VARIABILITY OF GJ 1214

Cited by 67 publications

References 39 publications

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

THEK2-ESPRINT PROJECT III: A CLOSE-IN SUPER-EARTH AROUND A METAL-RICH MID-M DWARF

Erratum: Physical properties, star-spot activity, orbital obliquity and transmission spectrum of the Qatar-2 planetary system from multicolour photometry

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MULTI-COLOR TRANSIT PHOTOMETRY OF GJ 1214b THROUGHBJHKsBANDS AND A LONG-TERM MONITORING OF THE STELLAR VARIABILITY OF GJ 1214

Cited by 67 publications

References 39 publications

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

ACCESS I. AN OPTICAL TRANSMISSION SPECTRUM OF GJ 1214b REVEALS A HETEROGENEOUS STELLAR PHOTOSPHERE

THEK2-ESPRINT PROJECT III: A CLOSE-IN SUPER-EARTH AROUND A METAL-RICH MID-M DWARF

Erratum: Physical properties, star-spot activity, orbital obliquity and transmission spectrum of the Qatar-2 planetary system from multicolour photometry

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MULTI-COLOR TRANSIT PHOTOMETRY OF GJ 1214b THROUGHBJHK_sBANDS AND A LONG-TERM MONITORING OF THE STELLAR VARIABILITY OF GJ 1214