Latham, David W., Bakos, Gáspár Á., Torres, Guillermo, Stefanik, Robert P., Noyes, Robert W., Kovács, Géza, ...
We report the identification of 32 transiting-planet candidates in HATNet field G205. We describe the procedures that we have used to follow up these candidates with spectroscopic and photometric...
HAT-P-9b: A Low Density Planet Transiting a Moderately Faint F star (2008)
Shporer, Avi, Bakos, Gaspar A., Bouchy, Francois, Pont, Frederic, Kovacs, Geza, Latham, Dave W., ...
We report the discovery of a planet transiting a moderately faint (V=12.3 mag) late F star, with an orbital period of 3.92289 +/- 0.00004 days. From the transit light curve and radial velocity...
DISTANCES TO NEARBY GALAXIES: COMBINING FRAGMENTARY DATA USING FOUR DIFFERENT METHODS (2007)
Dragan Huterer, Dimitar D. Sasselov
The primary distance indicators are established in our Galaxy and the Local Group. There are at least four different methods which give good distances: methods using proper motions, RR Lyraes,...
High-resolution spectroscopic follow-up of OGLE planetary (2007)
Transit Candidates In, Maciej Konacki, Guillermo Torres, Dimitar D. Sasselov, Saurabh Jha
We report the results of our campaign to follow-up spectroscopically several candidate extrasolar transiting planets from the OGLE-III survey in the direction of the Galactic center, announced in...
New Data and Improved Parameters for the Transiting Planet OGLE-TR-56b (2007)
Guillermo Torres, Maciej Konacki, Dimitar D. Sasselov, Saurabh Jha
We report new spectroscopic observations of the recently discovered transiting planet OGLE-TR-56b with the Keck/HIRES instrument. Our radial velocity measurements with errors of 100 m s 1 show clear...
Inevitability of Plate Tectonics on Super-Earths (2007)
Valencia, Diana, O'Connell, Richard J., Sasselov, Dimitar D.
The recent discovery of super-Earths (masses less or equal to 10 earth-masses) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which...
Detailed Models of super-Earths: How well can we infer bulk properties? (2007)
Valencia, Diana, Sasselov, Dimitar D., O'Connell, Richard J.
The field of extrasolar planets has rapidly expanded to include the detection of planets with masses smaller than that of Uranus. Many of these are expected to have little or no hydrogen and helium...
Radius and Structure models for the First Super-Earth Planet (2006)
Valencia, Diana, Sasselov, Dimitar D., O'Connell, Rirchard J.
With improving methods and surveys, the young field of extrasolar planets has recently expanded into a qualitatively new domain - terrestrial (mostly rocky) planets. The first such planets were...
Internal Structure of Massive Terrestrial Planets (2005)
Valencia, Diana, O'Connell, Richard J., Sasselov, Dimitar D.
Planetary formation models predict the existence of massive terrestrial planets and experiments are now being designed that should succeed in discovering them and measuring their masses and radii. We...
The Transit Light Curve Project. IV. Five Transits of the Exoplanet OGLE-TR-10b (2005)
Holman, Matthew J., Winn, Joshua N., Fuentes, Cesar I., Hartman, Joel D., Stanek, K. Z., Torres, Guillermo, ...
We present I and B photometry of five distinct transits of the exoplanet OGLE-TR-10b. By modeling the light curves, we find the planetary radius to be R_P = 1.06 +/- 0.08 R_Jup and the stellar radius...
Formation of Carbon Dwarfs (2005)
Steinhardt, Charles L., Sasselov, Dimitar D.
We consider the formation of dwarf carbon stars via accretion from a carbon AGB companion in light of the new 107 object sample of Downes et al. (2004). This sample is now large enough to allow good...
A transiting extrasolar giant planet around the star OGLE-TR-10 (2004)
Konacki, Maciej, Torres, Guillermo, Sasselov, Dimitar D., Jha, Saurabh
We report a transiting extrasolar giant planet around the star OGLE-TR-10 (orbital period = 3.1 days), which was uncovered as a candidate by the OGLE team in their photometric survey towards the...
Type I Migration in a Non-Isothermal Protoplanetary Disk (2004)
Jang-Condell, Hannah, Sasselov, Dimitar D.
We calculate rates of Type I migration of protoplanets in a non-isothermal three-dimensional protoplanetary disk, building upon planet-disk models developed in previous work. We find that including...
Testing blend scenarios for extrasolar transiting planet candidates. II. -- OGLE-TR-56 (2004)
Torres, Guillermo, Konacki, Maciej, Sasselov, Dimitar D., Jha, Saurabh
We re-examine the photometric and spectroscopic evidence available for the star OGLE-TR-56, recently discovered to harbor a giant planet presenting transits and orbiting with a period of 1.21 days....
Torres, Guillermo, Konacki, Maciej, Sasselov, Dimitar D., Jha, Saurabh
We report high-resolution spectroscopic follow-up observations of the faint transiting planet candidate OGLE-TR-33 (V = 14.7), located in the direction of the Galactic center. Small changes in the...
Torres, Guillermo, Konacki, Maciej, Sasselov, Dimitar D., Jha, Saurabh
In early 2003 our team announced the discovery of the second extrasolar transiting planet, around the faint star OGLE-TR-56 (V = 16.6), based on the detection of small changes in the radial velocity...
Jang-Condell, Hannah, Sasselov, Dimitar D.
We revisit the computation of a "snow line" in a passive protoplanetary disk during the stage of planetesimal formation. We examine how shadowing and illumination in the vicinity of a planet affects...
A transiting extrasolar giant planet around the star OGLE-TR-113 (2004)
Konacki, Maciej, Torres, Guillermo, Sasselov, Dimitar D., Pietrzynski, Grzegorz, Udalski, Andrzej, Jha, Saurabh, ...
We report the independent discovery of a new extrasolar transiting planet around OGLE-TR-113, a candidate star from the Optical Gravitational Lensing Experiment. Small radial-velocity variations have...
An Error Analysis of the Geometric Baade-Wesselink Method (2003)
Marengo, Massimo, Karovska, Margarita, Sasselov, Dimitar D., Sanchez, Mayly
We derive an analytic solution for the minimization problem in the geometric Baade-Wesselink method. This solution allows deriving the distance and mean radius of a pulsating star by fitting its...
New Data and Improved Parameters for the Transiting Planet OGLE-TR-56b (2003)
Torres, Guillermo, Konacki, Maciej, Sasselov, Dimitar D., Jha, Saurabh
We report new spectroscopic observations of the recently discovered transiting planet OGLE-TR-56b with the Keck/HIRES instrument. Our radial velocity measurements with errors of ~100 m/s show clear...
Limits on eclipses of the pre-main-sequence star KH 15D in the first half of the 20th century (2003)
Winn, Joshua N., Garnavich, Peter M., Stanek, K. Z., Sasselov, Dimitar D.
Over the last decade, the pre-main sequence star KH 15D has exhibited periodic eclipses that are surprisingly deep (~3 mag) and long-lasting (~40% of the 48.4-day period). The cause of the eclipses...
Konacki, Maciej, Torres, Guillermo, Sasselov, Dimitar D., Jha, Saurabh
We report the results of our campaign to follow-up spectroscopically several candidate extrasolar transiting planets from the OGLE-III survey in the direction of the Galactic center, announced in...
Radiative Transfer on Perturbations in Protoplanetary Disks (2003)
Jang-Condell, Hannah, Sasselov, Dimitar D.
We present a method for calculating the radiative tranfer on a protoplanetary disk perturbed by a protoplanet. We apply this method to determine the effect on the temperature structure within the...
Marengo, Massimo, Karovska, Margarita, Sasselov, Dimitar D., Armstrong, John T., Nordgren, Tyler E.
The geometric Baade-Wesselink method is one of the most promising techniques for obtaining a better calibration of the Cepheid period-luminosity relation by means of interferometric measurements of...
Cepheid Limb Darkening Models for the VLTI (2003)
Marengo, Massimo, Karovska, Margarita, Sasselov, Dimitar D., Papaliolios, Costas, Armstrong, J. T., Nordgren, Tyler
We present a new method to compute wavelength- and phase-dependent limb darkening corrections for classical Cepheids. These corrections are derived from hydrodynamic simulations and radiative...
The New Transiting Planet OGLE-TR-56b: Orbit and Atmosphere (2003)
Motivated by the identification of the very close-in extrasolar giant planet OGLE-TR-56b, we explore the implications of its existence on problems of tidal dissipation, planet migration, and...
HD 209458: Physical Parameters of the Parent Star and the Transiting Planet (2001)
Cody, A., Sasselov, Dimitar D.
The Sun-like star HD209458 harbors a close-in giant planet which transits across the star's disk, and thus allows an unprecedented access to the basic parameters of the planet, given a certain...
DIRECT Distances to Local Group Galaxies (1999)
The two nearby galaxies, M31 and M33, are stepping stones for most of our current efforts to understand the evolving universe at large scales. We are undertaking a long term project, called DIRECT,...
How exactly did the Universe become neutral? (1999)
Seager, Sara, Sasselov, Dimitar D., Scott, Douglas
We present a refined treatment of H, He I, and He II recombination in the early Universe. The difference from previous calculations is that we use multi-level atoms and evolve the population of each...
A New Calculation of the Recombination Epoch (1999)
Seager, Sara, Sasselov, Dimitar D., Scott, Douglas
We have developed an improved recombination calculation of H, HeI, and HeII in the early Universe which involves a line-by-line treatment of each atomic level. We find two major differences compared...
Surface Imaging by Microlensing - Exploring Depth in Stellar Atmospheres (1998)
Gravitational microlensing is a new technique for studying the surfaces of distant stars. A point mass lens, usually a low-mass star from the disk, will typically resolve the surface of a red giant...
Pulsating Stellar Atmospheres (1997)
We review the basic concepts, the present state of theoretical models, and the future prospects for theory and observations of pulsating stellar atmospheres. Our emphasis is on radially pulsating...
The Chromaticity of Microlensing (Surface Imaging of Stars) (1997)
Gravitational microlensing is not achromatic when the star being microlensed is resolved by the lens. We show how narrow-band photometry and moderate- to high-resolution spectroscopy can be used to...
Radii and Distances of Cepheids, I., Method and Measurement Errors (1996)
Krockenberger, Martin, Sasselov, Dimitar D., Noyes, Robert W.
We develop a formulation of the Baade-Wesselink method which uses the Fourier coefficients of the observables. We derive an explicit, analytic expression to determine the mean radius from each...
Distances to Nearby Galaxies: Combining Fragmentary Data Using Four Different Methods (1995)
Huterer, Dragan, Sasselov, Dimitar D., Schechter, Paul L.
The primary distance indicators are established in our Galaxy and the Local Group. There are at least four different methods which give good distances: methods using proper motions, RR Lyraes,...
New Bounds on Omega Baryons from Observational Big Bang Nucleosynthesis (1994)
Sasselov, Dimitar D., Goldwirth, Dalia
We re-examine the systematic errors in the determination of the primordial helium abundance, $Y_{\rm P}$. We find that the systematics are significantly larger than the statistical errors. The...