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- Heather A. Knutson, David B. Charbonneau, +6 authors S . Thomas Megeath
- Nature
- 2007

'Hot Jupiter' extrasolar planets are expected to be tidally locked because they are close (<0.05 astronomical units, where 1 au is the average Sun-Earth distance) to their parent stars, resulting in permanent daysides and nightsides. By observing systems where the planet and star periodically eclipse each other, several groups have been able to estimate the… (More)

- Kaisey S. Mandel, E. Agol
- 2002

We present exact analytic formulae for the eclipse of a star described by quadratic or nonlinear limb darkening. In the limit that the planet radius is less than a tenth of the stellar radius, we show that the exact light curve can be well approximated by assuming the region of the star blocked by the planet has constant surface brightness. We apply these… (More)

We present results from Spitzer Space Telescope observations of the mid-infrared phase variations of three short-period extrasolar planetary systems: HD 209458, HD 179949 and 51 Peg.We gathered Infrared Array Camera (IRAC) images in multiple wavebands (3.6 μm or 4.5 μm, and 8 μm) at eight phases of each planet’s orbit. We find the uncertainty in relative… (More)

- N B Cowan, E. Agol, +8 authors David B. Charbonneau
- 2009

When Earth-mass extrasolar planets first become detectable, one challenge will be to determine which of these worlds harbor liquid water, a widely used criterion for habitability. Some of the first observations of these planets will consist of disc-averaged, time-resolved broadband photometry. To simulate such data, the Deep Impact spacecraft obtained light… (More)

- E. Agol, Julian Krolik
- 1988

Magnetic connections to the plunging region can exert stresses on the inner edge of an accretion disk around a black hole. We recompute the relativistic corrections to the thin-disk dynamics equations when these stresses take the form of a time-steady torque on the inner edge of the disk. The additional dissipation associated with these stresses is… (More)

- Ashlee N. Wilkins, Peter R. McCullough, +16 authors A. P. Showman
- 2013

Exoplanetary transmission spectroscopy in the near-infrared using Hubble/NICMOS is currently ambiguous because different observational groups claim different results from the same data, depending on their analysis methodologies. Spatial scanning with Hubble/WFC3 provides an opportunity to resolve this ambiguity. We here report WFC3 spectroscopy of the giant… (More)

- JUPITER KEPLER-13Ab, Avi Shporer, +13 authors Kamen O. Todorov
- 2014

Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet’s occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations… (More)

- E. Agol, Julian Krolik
- 2008

We show how analysis of a quasar high-magnification microlensing event may be used to construct a map of the frequency-dependent surface brightness of the quasar accretion disk. The same procedure also allows determination of the disk inclination angle, the black hole mass (modulo the caustic velocity), and possibly the black hole spin. This method depends… (More)

- A . Eigenbrod, Frédéric Courbin, Dominique Sluse, Georges Meylan, E. Agol
- 2007

Aims. We present the results of the first long-term spectroscopic monitoring of a gravitationally lensed quasar, for QSO 2237+0305: the Einstein Cross. We show that chromatic microlensing-induced variations constantly affect the spectra of all four images of the lensed quasar. The goal of the present paper is to present the observational facts to later be… (More)

- E. Agol, Jason H. Steffen, Re’em Sari, Will Clarkson
- 2005

The transits of a planet on a Keplerian orbit occur at time intervals exactly equal to the period of the orbit. If a second planet is introduced the orbit is not Keplerian and the transits are no longer exactly periodic. We compute the magnitude of these variations in the timing of the transits, δt. We investigate analytically several limiting cases: (i)… (More)