Kepler's equation hamugeš-e Kepler Fr.: équation de Kepler An equation that enables the position of a body in an elliptical orbit to be calculated at any given time from its orbital elements. It relates the → mean anomaly of the body to its → eccentric anomaly. |
Kepler's first law qânun-e naxost-e Kepler (#) Fr.: première loi de Kepler Planets move in elliptical paths, with the Sun at one focus of the ellipse (year 1609). |
Kepler's laws qânunhâ-ye Kepler (#) Fr.: lois de Kepler 1) The planets move about the Sun in ellipses, at one focus of which the Sun is situated. |
Kepler's second law qânun-e dovom-e Kepler (#) Fr.: deuxième loi de Kepler A line joining a planet to the Sun sweeps out equal areas in equal intervals of time (year 1609). |
Kepler's star setâre-ye Kepler (#) Fr.: étoile de Kepler A → supernova in → Ophiuchus, first observed on 1604 October 9, and described by Johannes Kepler in his book De stella nova (1606). It reached a maximum → apparent magnitude of -3 in late October. The star remained visible for almost a year. The → light curve is that of a → Type Ia supernova. The → supernova remnant consists of a few filaments and brighter knots at a distance of about 30,000 → light-years. It is the radio source 3C 358. Also known as SN 1604 and Kepler's supernova. |
Kepler's third law qânun-e sevom-e Kepler (#) Fr.: troisième loi de Kepler The ratio between the square of a planet's → orbital period (P) to the cube of the mean distance from the Sun (a) is the same for all planets: P^{2}∝ a^{3} (year 1618). More accurately, P^{2} = (4π^{2}a^{3}) / [G(M_{1} + M_{2})], where M_{1} and M_{2} are the masses of the two orbiting objects in → solar masses and G is the → gravitational constant. In our solar system M_{1} = 1. The → semi-major axis size (a is expressed in → astronomical units and the period (P) is measured in years. |