Pericentrikus

Pericentrikus is an adjective used in Hungarian and in scientific contexts to describe relations to the pericenter, the point of closest approach to a central focus, or to the region around a centromere on a chromosome. The term is applied in several disciplines, with distinct but related meanings.

In astronomy and orbital mechanics, pericentric (or pericentric in Hungarian usage) refers to the position of an orbiting body when it is nearest to the body it orbits. The distance at this point, called the pericenter or periapsis distance, is a key parameter of an orbit and is typically shorter than the semi-major axis times one minus eccentricity (rp = a(1 − e)). Pericentric passages are often linked to observable phenomena such as increased brightness, tidal interactions, or variations in velocity, depending on the system.

In genetics and cytogenetics, pericentric describes chromosomal rearrangements that involve the centromere. A pericentric inversion, for example, flips a segment of a chromosome that includes the centromere, altering the lengths of the chromosome arms. This contrasts with paracentric inversions, which do not include the centromere. Pericentric changes can affect recombination patterns and fertility in carriers and are studied in evolutionary biology and clinical genetics.

In chromatin biology, the term can refer to the pericentromeric region, the chromosomal neighborhood around the centromere, often characterized by specific heterochromatin and repetitive sequences.

Etymologically, pericentrikus derives from peri- meaning around and centrum meaning center. See also pericenter, periapsis, pericentromeric region.