Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 0707.3809

Characterization of the hot Neptune GJ 436b with Spitzer and ground-based observations

B. -O. Demory·M. Gillon·T. Barman·X. Bonfils·M. Mayor·T. Mazeh·D. Queloz·S. Udry·F. Bouchy·X. Delfosse·T. Forveille·F. Mallmann·F. Pepe·C. Perrier
View original source ↗Read source document ↗Export metadata ↓

Abstract

We present Spitzer Space Telescope infrared photometry of a secondary eclipse of the hot Neptune GJ436b. The observations were obtained using the 8-micron band of the InfraRed Array Camera (IRAC). The data spanning the predicted time of secondary eclipse show a clear flux decrement with the expected shape and duration. The observed eclipse depth of 0.58 mmag allows us to estimate a blackbody brightness temperature of T_p = 717 +- 35 K at 8 microns. We compare this infrared flux measurement to a model of the planetary thermal emission, and show that this model reproduces properly the observed flux decrement. The timing of the secondary eclipse confirms the non-zero orbital eccentricity of the planet, while also increasing its precision (e = 0.14 +- 0.01). Additional new spectroscopic and photometric observations allow us to estimate the rotational period of the star and to assess the potential presence of another planet.

Explore related subjects

astro-ph

Keep this discovery

BibTeXRIS

B. -O. Demory, M. Gillon, T. Barman, X. Bonfils, M. Mayor, T. Mazeh, D. Queloz, S. Udry, F. Bouchy, X. Delfosse, T. Forveille, F. Mallmann, F. Pepe, C. Perrier. 2007-09-14. Characterization of the hot Neptune GJ 436b with Spitzer and ground-based observations. https://doi.org/10.1051/0004-6361%3A20078354

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2016

The Interpretation of Inertial Force and The Existence of Absolute Background

The formalism of classical particle dynamics is reinvestigated according to the basic requirement of causal consistency, and a new equation of particle dynamics, which is more general and more in line with classical mechanics experiments than Newton's second law, is obtained. More importantly, the inertial frame of reference is no longer required and the inertial force is no longer introduced by hand. The new dynamical equation can be straightforwardly applied in any reference frame as long as which is irrotational with respect to the absolute background of the universe. The nature of the inertial force is nothing but the real forces acting on the reference object. The essence of this reform of classical particle dynamics is just a drawback of traditional formalism in Newtonian mechanics being corrected. However, it may be more important that a logical derivation of this new particle dynamics equation strongly suggests the existence of an absolute background for the whole space of the universe. In physical concepts, the absolute background for space does not conflict with the relative length of the base unit of space in Einstein's Special Relativity and General Relativity. Furthermore, the size of the base unit of space should essentially be understood as the length of the line segment, which is cut from the absolute background of space by the intrinsic physical events.

astro-ph↗
arXiv2015

The exact numerical treatment of inflationary models

The precision reached by the recent CMB measurements gives new insights into the shape of the primordial power spectra of the cosmological perturbations. In the context of inflationary cosmology, this implies that the CMB data are now sensitive to the form of the inflaton potential. Most of the current approaches devoted to the derivation of the inflationary primordial power spectra, or to the inflaton potential reconstruction problem, rely on approximate analytical treatments that may break down for exotic models. In this article, we numerically solve the inflationary evolution of both the background and all the perturbed quantities to extract the primordial power spectra exactly. Such a method solely relies on General Relativity and linear perturbation theory. More than providing a tool to test analytical approximations, one may consider, without complications, the treatment of non-standard inflationary models as those involving several fields, eventually non-minimally coupled to gravity. The usefulness of the exact numerical approach to deal with CMB data is illustrated by analysing the WMAP third year data in the context of single field models. For this purpose, we introduce a new inflationary related parameter encoding the basic properties of the reheating era. This reheating parameter has significant observable effects and provides a self-consistency test of inflationary models. As a working example, the marginalised probability distributions of the reheating and potential parameters associated with the small field models are presented.

astro-ph↗
arXiv2015

Mass estimates from stellar proper motions: The mass of $ω$ Centauri

A projected mass estimator and a maximum likelihood estimator are developed to best determine the mass of stellar clusters from proper motion data. Both methods effectively account and correct for errors in the velocities, and provide an unbiased and robust estimate of the cluster mass. Using an extensive proper motion study of $ω$ Centauri by van Leeuwen et al. (2000), we estimate the mass of $ω$ Centauri using these two different methods to be $2.8 \times 10^{6} M_{\odot} \left[d/5.1 kpc\right]^{3}$. Within this modeling context, the statistical error is $3\%$ and the systematic error is $4\%$.

astro-ph↗