Solar analog (–0.21) for solar twin. 16 Cygni B is sometimes noted as twin, but is part of a triple star system and is very old for a solar twin at over 9 Gyr. Another way of defining solar twin is as a "habstar" — a star with qualities believed to be particularly hospitable to an Earth-like planet. Qualities considered include variability, mass, age, metallicity, and close companions. The requirement that the star remain on the main sequence for at least 3 Ga sets an upper limit of approximately 1.5 solar masses, corresponding to a hottest spectral type of F5 V. Such
Max Planck Institute for Solar System Research interactions with the solar wind, the atmospheric dynamics, or the generation of the terrestrial magnetic field by means of currents deep in the iron core of our planet. In addition, the Institute has along tradition in cometary research. A major highlight was the camera developed at the Institute for the ESA spacecraft Giotto which delivered the first photographs ever of a comet’s nucleus in 1986. A particular challenge was the development of numerous scientific instruments for the ESA Mission Rosetta, such as cameras, chemical analyzers, and essential components for the landing module Philae. Rosetta was launched in 2004, and matched