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" Exoplanet searches
with microlensing " A.F. Zakharov (Institute of
Theoretical and Experimental Physics) Abstract: Different regimes
of gravitational lensing depend on masses of lens and correspond roughly an
angular distance between images. If a gravitational lens has a typical
stellar mass, this regime is named as microlensing because a typical angular
distance between images is about microarcseconds in the case if sources and
lenses are located at cosmological distances. An angular distance depends as
a squared root of a lens mass, therefore, if a lens has a typical Earth-like
planet mass $10^{-6} M_{\odot}$, the regime is called such as nanolensing.
Thus, generally speaking, one can call a regime with a planet mass lens such
as nanolensing (independently on locations of lenses and sources). So, one
can name searches for planets with gravitational lens method as gravitational
nanolensing. There are different methods to find exoplanets as such radial
spectral shifts, astrometrical measurements, transits, pulsar timing etc.
Gravitational microlensing (including pixel-lensing) is among the most
promising techniques if we are interested to find Earth-like planets at distances about a few
astronomical units from the host star. |
