Zeta Persei (ζ Per, ζ Persei) is a
star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
in the northern
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The first constellati ...
of
Perseus. With an
apparent visual magnitude of 2.9,
[ it can be readily seen with the naked eye. Parallax measurements place it at a distance of about from ]Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
,[ though measurements of its Ca II lines place it at .][
]
Description
This is a lower luminosity supergiant star with a stellar classification of B1 Ib.[ This is an enormous star, with an estimated 26–27][ times the Sun's radius and 13–16 times the Sun's mass.][ It has about 47,000 times the luminosity of the Sun and it is radiating this energy at an effective temperature of 20,800 K,][ giving it the blue-white hue of a B-type star.][ The ]spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
displays anomalously high levels of carbon.[ Zeta Persei has a strong stellar wind that is expelling times the mass of the Sun per year, or the equivalent of the Sun's mass every 4.3 million years.][
Zeta Persei has a 9th magnitude companion at an angular separation of 12.9 arcseconds. The two stars have the same proper motion, so they may be physically associated. If so, they are separated by at least 4,000 ]Astronomical Unit
The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...
s.[ Zeta Persei is a confirmed member of the Perseus OB2 association (Per OB2), also called the Zeta Persei association, which is a moving group of stars that includes 17 massive, high luminosity members with spectral types of O or B, giving them a blue hue. These stars have a similar trajectory through space,][ suggesting they originated in the same ]molecular cloud
A molecular cloud—sometimes called a stellar nursery if star formation is occurring within—is a type of interstellar cloud of which the density and size permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, ...
and are about the same age.[
]
Ambiguity
Some sources, including Starry Night (planetarium software), an atlas, and a web siteYour Sky Object Catalogue: Named Stars
/ref> attribute the name 'Atik' to Zeta Persei instead of nearby Omicron Persei.
See also
* HD 121228 - Same spectral class
References
External links
*
{{DEFAULTSORT:Zeta Persei
B-type supergiants
Perseus (constellation)
Persei, Zeta
Durchmusterung objects
Persei, 44
024398
018246
1203
Atik