What is a Vulcanoid?
A Vulcanoid is an object in a long-term stable orbit around our Sun whose mean distance to the Sun is less than that of Mercury’s. Mercury’s mean distance from the Sun is about 0.387 a.u. (about 57.9 million km). Any object whose orbit is completely inside Mercury’s orbit would be a Vulcanoid. However, because Mercury’s orbit is elliptical, it is possible for an object to cross Mercury’s orbit and still be a Vulcanoid.
