The exoplanet Zephyrus-7 orbits the distant star Eldoria. The orbit of Zephyrus-7 may be assumed to be a circle. The centre of Zephyrus-7 is at a distance of 1.45 × 108 km from the centre of Eldoria and it has an orbital speed of 2.95 × 104 m s-1.
State the direction of the gravitational force which keeps Zephyrus-7 in its orbit.
Calculate the orbital period T T\,T of Zephyrus-7 in seconds.
Calculate the mass M M\,M of the star Eldoria. (The gravitational constant G=6.67×10−11 m3 kg−1 s−2G = 6.67 \times 10^{-11}\text{ m}^3\text{ kg}^{-1}\text{ s}^{-2}G=6.67×10−11 m3 kg−1 s−2)