Astronomy & Astrophysics is a peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
A red dwarf (or M dwarf) is a small and relatively cool star on the main sequence, of M spectral type.
The Astronomical Journal (often abbreviated AJ in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by IOP Publishing.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.