Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

M. Gillon; B. O. Demory; T. Barman; X. Bonfils; T. Mazeh; F. Pont; S. Udry; M. Mayor; D. Queloz

doi:10.1051/0004-6361:20078283

Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

M. Gillon^*, B. O. Demory, T. Barman, X. Bonfils, T. Mazeh, F. Pont, S. Udry, M. Mayor, D. Queloz

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

111 Scopus citations

Abstract

We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 μm band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and the weak limb-darkening in the 8 μm IRAC band allow us to derive (assuming M = 0.44 ±0.04 M_⊙ for the primary) a precise value for the planetary radius (4.19_-0.16^+0.21 R _⊕), the stellar radius (0.463_-0.017^+0.022 R_⊙) the orbital inclination (85.90° _-0.18°^+0.19°) and transit timing ((2454280.78186_-0.00008^+0.00015 HJD). Assuming current planet models, an internal structure similar to that of Neptune with a small H/He envelope is necessary to account for the measured radius of GJ 436b.

Original language	English
Pages (from-to)	L51-L54
Journal	Astronomy and Astrophysics
Volume	471
Issue number	3
DOIs	https://doi.org/10.1051/0004-6361:20078283
State	Published - Sep 2007

Keywords

Eclipses
Infrared: general
Planetary systems
Stars: individual: GJ 436
Techniques: photometric

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10.1051/0004-6361:20078283

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title = "Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b",

abstract = "We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 μm band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and the weak limb-darkening in the 8 μm IRAC band allow us to derive (assuming M = 0.44 ±0.04 M⊙ for the primary) a precise value for the planetary radius (4.19-0.16+0.21 R ⊕), the stellar radius (0.463-0.017+0.022 R⊙) the orbital inclination (85.90° -0.18°+0.19°) and transit timing ((2454280.78186-0.00008+0.00015 HJD). Assuming current planet models, an internal structure similar to that of Neptune with a small H/He envelope is necessary to account for the measured radius of GJ 436b.",

keywords = "Eclipses, Infrared: general, Planetary systems, Stars: individual: GJ 436, Techniques: photometric",

author = "M. Gillon and Demory, {B. O.} and T. Barman and X. Bonfils and T. Mazeh and F. Pont and S. Udry and M. Mayor and D. Queloz",

year = "2007",

month = sep,

doi = "10.1051/0004-6361:20078283",

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T1 - Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

AU - Gillon, M.

AU - Demory, B. O.

AU - Barman, T.

AU - Bonfils, X.

AU - Mazeh, T.

AU - Pont, F.

AU - Udry, S.

AU - Mayor, M.

AU - Queloz, D.

PY - 2007/9

Y1 - 2007/9

N2 - We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 μm band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and the weak limb-darkening in the 8 μm IRAC band allow us to derive (assuming M = 0.44 ±0.04 M⊙ for the primary) a precise value for the planetary radius (4.19-0.16+0.21 R ⊕), the stellar radius (0.463-0.017+0.022 R⊙) the orbital inclination (85.90° -0.18°+0.19°) and transit timing ((2454280.78186-0.00008+0.00015 HJD). Assuming current planet models, an internal structure similar to that of Neptune with a small H/He envelope is necessary to account for the measured radius of GJ 436b.

AB - We present Spitzer Space Telescope infrared photometry of a primary transit of the hot Neptune GJ 436b. The observations were obtained using the 8 μm band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data and the weak limb-darkening in the 8 μm IRAC band allow us to derive (assuming M = 0.44 ±0.04 M⊙ for the primary) a precise value for the planetary radius (4.19-0.16+0.21 R ⊕), the stellar radius (0.463-0.017+0.022 R⊙) the orbital inclination (85.90° -0.18°+0.19°) and transit timing ((2454280.78186-0.00008+0.00015 HJD). Assuming current planet models, an internal structure similar to that of Neptune with a small H/He envelope is necessary to account for the measured radius of GJ 436b.

KW - Eclipses

KW - Infrared: general

KW - Planetary systems

KW - Stars: individual: GJ 436

KW - Techniques: photometric

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SP - L51-L54

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

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ER -

Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

Abstract

Keywords

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