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One possibility for detecting low-amplitude pulsational variations is through gravitational microlensing. During a microlensing event, the temporary brightness increase leads to improvement in the signal-to-noise ratio, and thereby better…

Solar and Stellar Astrophysics · Physics 2021-09-01 Sedighe Sajadian , Richard Ignace , Hilding Neilson

We consider microlensing of an elliptical source crossing a fold caustic. We derive a simple expression for the light curve of a source with uniform surface brightness that is accurate to third order in the ellipticity e (yielding errors of…

Astrophysics · Physics 2007-05-23 B. Scott Gaudi , Zoltan Haiman

The phenomenon of microlensing has successfully been used to detect extrasolar planets. By observing characteristic, rare deviations in the gravitational microlensing light curve one can discover that a lens is a star--planet system. In…

Earth and Planetary Astrophysics · Physics 2014-04-15 Krzysztof Rybicki , Łukasz Wyrzykowski

Point lens microlensing events with impact parameter close to the source stellar radius allow the observer to study the surface brightness profile of the lensed source. We have examined the effect of photospheric star spots on multicolour…

Astrophysics · Physics 2009-11-07 M. A. Hendry , H. M. Bryce , D. Valls-Gabaud

If a gravitational microlensing event is caused by a widely separated binary lens and the source approaches both lens components, the source flux is successively magnified by the individual lenses: double microlensing events. If events are…

Astrophysics · Physics 2009-11-07 Cheongho Han , Byeong-Gon Park , Wonyong Han , Young Woon Kang

An extrasolar planet can be detected via microlensing from the perturbation it makes in the smooth lensing light curve of the primary. In addition to the conventional photometric microlensing, astrometric observation of the center-of-light…

Astrophysics · Physics 2009-11-10 Cheongho Han , Kyongae Chang

We investigate the microlensing effects on a source star surrounded by a circumstellar disk, as a function of wavelength. The microlensing light curve of the system encodes the geometry and surface brightness profile of the disk. In the…

Astrophysics · Physics 2009-11-13 Zheng Zheng , Brice Ménard

Planetary companions to the source stars of a caustic-crossing binary microlensing events can be detected via the deviation from the parent light curves created when the caustic magnifies the star light reflecting off the atmosphere or…

Astrophysics · Physics 2009-11-07 B. Scott Gaudi , Heon-Young Chang , Cheongho Han

We consider the effects induced by the presence of hot and cold spots on the source star in the light curves of simulated microlensing events due to either single or binary lenses taking into account the rotation of the source star and the…

Solar and Stellar Astrophysics · Physics 2017-03-23 Mosè Giordano , Achille A. Nucita , Francesco De Paolis , Gabriele Ingrosso

We re-consider the polarization of the star light that may arise during microlensing events due to the high gradient of magnification across the atmosphere of the source star, by exploring the full range of microlensing and stellar physical…

Solar and Stellar Astrophysics · Physics 2015-06-23 G. Ingrosso , S. Calchi Novati , F. De Paolis , Ph. Jetzer , A. A. Nucita , F. Strafella

Microlensing of extended stellar sources in the LMC and Galaxy by low mass lenses can produce variable polarisation. The characteristics of the polarisation and flux profiles can provide considerable information about the lens geometry, and…

Astrophysics · Physics 2015-06-24 J. F. L. Simmons , A. M. Newsam , J. P. Willis

We propose a direct method to detect close-in giant planets orbiting stars in the Galactic bulge. This method uses caustic-crossing binary microlensing events discovered by survey teams monitoring the bulge to measure light from a planet…

Astrophysics · Physics 2009-10-31 David S. Graff , B. Scott Gaudi

This study investigates the polarization characteristics of solitonic boson stars surrounded by a thin accretion disk. By comparing their polarization images with corresponding optical images, we find a positive correlation between the…

General Relativity and Quantum Cosmology · Physics 2025-08-19 Xiao-Xiong Zeng , Chen-Yu Yang , Hao Yu , Ke-Jian He

In a line caustic crossing microlensing event, the caustic line moving across the surface of the source star provides a direct method to measure the integrated luminosity profile of the star. Combined with the enormous brightening at the…

Astrophysics · Physics 2007-05-23 Sun Hong Rhie , David P. Bennett

We present results of numerical simulations of flux and linear polarization variations in transiting exoplanetary systems, caused by the host star disk symmetry breaking. We consider different configurations of planetary transits depending…

Solar and Stellar Astrophysics · Physics 2015-06-17 N. M. Kostogryz , T. M. Yakobchuk , S. V. Berdyugina

Over the past decade, microlensing has developed into a powerful tool to study stellar astrophysics, especially stellar atmospheres, stellar masses, and binarity. I review this progress. Stellar atmospheres can be probed whenever the source…

Astrophysics · Physics 2016-08-30 Andrew Gould

Recent studies have demonstrated that detailed monitoring of gravitational microlensing events can reveal the presence of planets orbiting the microlensed source stars. With the potential of probing planets in the Galactic Bulge and…

Astrophysics · Physics 2009-11-06 Ceri E. Ashton , Geraint F. Lewis

If stars at the lower end of the main sequence are responsible for the microlensing events observed in the Galactic bulge, then light from the lensing star contributes to the observed brightness. The background and lensing stars generally…

Astrophysics · Physics 2009-10-22 Marc Kamionkowski

Much interest has been generated recently by the ongoing MACHO, EROS and OGLE projects to identify gravitationally lensed stars from the Large Magellanic Cloud and Galactic bulge, and the positive identification of several events (Alcock et…

Astrophysics · Physics 2007-05-23 J. F. L. Simmons , J. P. Willis , A. Newsam

We consider small-scale spheroidal clusters of weakly interacting massive particles in our Galaxy as non-compact gravitational microlenses and predict the appearance of caustics in the plane of a lensed source. The crossing of these…

Astrophysics · Physics 2010-04-30 M. B. Bogdanov , A. M. Cherepashchuk