Rotation of the line of apsides in the plane of the orbit in the same direction as the revolution of the secondary body. The major axis of the Earth's orbit rotates by 11.6 arcseconds per year.
The point of greatest or least distance of the orbit of a celestial body from a center of attraction. The closest point is the periapsis, the further point the apoapsis.
Stars of spectral type A in which lines of ionized metals and rare-earth elements are abnormally enhanced. Such stars have unusually strong magnetic fields, thousands of times stronger than the Sun's
typical surface field. Ap stars are generally slow rotators because of magnetic braking.
Stars of spectral type A in which lines of ionized metals and rare-earth elements are abnormally enhanced. Such stars have unusually strong magnetic fields, thousands of times stronger than the Sun's
typical surface field. Ap stars are generally slow rotators because of magnetic braking.
Stars of spectral type A in which lines of ionized metals and rare-earth elements are abnormally enhanced. Such stars have unusually strong magnetic fields, thousands of times stronger than the Sun's
typical surface field. Ap stars are generally slow rotators because of magnetic braking.
An aquatic ecosystem is an ecosystem located in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aq
uatic ecosystems are marine ecosystems and freshwater ecosystems.