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
Sustain Our Planet a variety of energy and sustainability assessments that determine the energy usage and carbon emissions generated as a result of current and future business activities. Sustain Our Planet works with businesses to calculate, track, and reduce their carbon footprint. In 2009 Sustain Our Planet launched its Carbon Impact Assessment which analyzes energy usage and the overall environmental impact of a client’s business operations. This includes the calculation and analysis of the business' carbon footprint that is broken down by energy use, business miles driven, and company air travel. The Carbon Impact Assessment is a comprehensive report that includes a detailed