Zeta Herculis
Encyclopedia
Zeta Herculis is a binary star
system in the constellation
Hercules. The primary star is a sub-giant that is somewhat larger than the Sun
and has just begun to evolve away from the main sequence
. It is orbited by a smaller and fainter star that is separated from the primary by just over 1 arcsec
. The stars orbit each other with a period of 34.5 years and a semi-major axis of 1.36". Stars A & B are separated from each other by an average separation of 14.65 AUs and swing as close as 8 AUs and as far away as 21.3 AUs.
This system forms part of the Zeta Herculis moving group
of stars. This group includes: δ Trianguli
, φ2 Pavonis
, ζ Reticuli
, 1 Hydrae, Gl 456, Gl 678
, and Gl 9079.
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
system in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Hercules. The primary star is a sub-giant that is somewhat larger than the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and has just begun to evolve away from the main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
. It is orbited by a smaller and fainter star that is separated from the primary by just over 1 arcsec
Arcsec
Arcsec may refer to:* arcsecond, a unit of angular measurement* arcsecant, an inverse trigonometric function...
. The stars orbit each other with a period of 34.5 years and a semi-major axis of 1.36". Stars A & B are separated from each other by an average separation of 14.65 AUs and swing as close as 8 AUs and as far away as 21.3 AUs.
This system forms part of the Zeta Herculis moving group
Zeta Herculis Moving Group
Zeta Herculis Moving Group is a set of stars that share a common motion through space.The existence of this moving group was first published in 1958 by Olin J. Eggen. Based upon the high velocity motion of the star Zeta Herculis through space, he searched for stars that were following a similar...
of stars. This group includes: δ Trianguli
Delta Trianguli
Delta Trianguli is a spectroscopic binary star system approximately away in the constellation of Triangulum. The primary star is a yellow dwarf, while the secondary star is thought to be an orange dwarf...
, φ2 Pavonis
Phi2 Pavonis
Phi² Pavonis , also known as HD 196378, is a yellow-white dwarf star approximately 82 light-years away in the constellation of Pavo . It is evolving into a subgiant....
, ζ Reticuli
Zeta Reticuli
Zeta Reticuli is a binary star system located about away from Earth. It is located in the constellation Reticulum, and is visible to the unaided eye in very dark skies...
, 1 Hydrae, Gl 456, Gl 678
Gliese 678
Gliese 678 is a spectroscopic binary star system approximately 60 light-years away in the constellation of Ophiuchus.This system is in the Zeta Herculis moving group, which is of low metallicity stars, 5 billion years old...
, and Gl 9079.