A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more visible stars. An association is primarily identified by commonalities in its member stars' movement vectors, ages, and chemical compositions. These shared features indicate that the members share a common origin. Nevertheless, they have become gravitationally unbound, unlike star clusters, and the member stars will drift apart over millions of years, becoming a moving group as they scatter throughout their neighborhood within the galaxy.
Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light-years (19.4 pc) from the Solar System, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 20 to 26 million years old, although it is already in the main sequence stage of its evolution. Beta Pictoris is the title member of the Beta Pictoris moving group, an association of young stars which share the same motion through space and have the same age.
Beta Scorpii is a multiple star system in the southern zodiac constellation of Scorpius. It bore the traditional proper name of Acrab, though the International Astronomical Union now regards that name as applying only to the β Scorpii Aa component.
HD 147513 is a star in the southern constellation of Scorpius. It was first catalogued by Italian astronomer Piazzi in his star catalogue as "XVI 55". With an apparent magnitude of 5.38, according to the Bortle scale it is visible to the naked eye from suburban skies. Based upon stellar parallax measurements by the Hipparcos spacecraft, HD 147513 lies some 42 light years from the Sun.
Sigma Scorpii, is a multiple star system in the constellation of Scorpius, located near the red supergiant Antares, which outshines it. This system has a combined apparent visual magnitude of +2.88, making it one of the brighter members of the constellation. Based upon parallax measurements made during the Hipparcos mission, the distance to Sigma Scorpii is roughly 696 light-years (214 parsecs). North et al. (2007) computed a more accurate estimate of 568+75
−59 light years.
Pi Scorpii or π Scorpii, is a triple star system in the southern constellation of Scorpius. With a combined apparent magnitude of 2.9, it can be easily seen with the naked eye. Parallax measurements yield an estimated distance of around 590 light-years from the Sun.
Alpha Lupi is a blue giant star, and the brightest star in the southern constellation of Lupus. According to the Bortle Dark-Sky Scale, its apparent visual magnitude of 2.3 makes it readily visible to the naked eye even from highly light-polluted locales. Based upon parallax measurements made during the Hipparcos mission, the star is around 460 light-years from the solar system. It is one of the nearest supernova candidates.
Kappa Centauri is a binary star in the southern constellation of Centaurus. With an apparent visual magnitude of +3.14, it can be viewed with the naked eye on a dark night. Parallax measurements place it at an estimated distance of 380 light-years from Earth.
The Scorpius–Centaurus association is the nearest OB association to the Sun. This stellar association is composed of three subgroups and its distance is about 130 parsecs or 420 light-years. Analysis using improved Hipparcos data has brought the number of known members to 436. The cluster shows a continuous spread of stars with no apparent need for subclassification.
Beta Lupi or Kekouan, is a star in the southern constellation of Lupus. It has an apparent visual magnitude of 2.7, making it readily visible to the naked eye. Based upon parallax measurements, this star is located at a distance of about 383 light-years from Earth.
Delta Lupi is a star in the southern circumpolar constellation of Lupus. In traditional Chinese astronomy, it is "the 2nd (star) of the Cavalry Officer" (騎官二). With an apparent visual magnitude of 3.2, it is the fourth-brightest star in the constellation. The distance to this star has been measured using the parallax technique, yielding an estimate of roughly 900 light-years with a 15% margin of error.
Alpha Muscae, Latinized from α Muscae, is a star in the southern circumpolar constellation of Musca. With an apparent visual magnitude of +2.7, it is the brightest star in the constellation. The distance to this star has been determined using parallax measurements, giving an estimate of about 315 light-years from Earth.
The TW Hydrae association is a group of very young low-mass stars and substellar objects located approximately 25–75 parsecs from Earth. They share a common motion and appear to all be roughly the same age, 10±3 million years old. It is the youngest such association within 100 pc from Earth.
HD 15115 is a single star in the equatorial constellation of Cetus. It is readily visible in binoculars or a small telescope, but is considered too dim to be seen with the naked eye at an apparent visual magnitude of 6.76. The distance to this object is 160 light years based on parallax, and it is slowly drifting further away at the rate of about 1 km/s. It has been proposed as a member of the Beta Pictoris moving group or the Tucana-Horologium association of co-moving stars; there is some ambiguity as to its true membership.
UScoCTIO 108 is a binary system, approximately 470 light-years away in the Upper Scorpius (USco) OB association. The primary, UScoCTIO 108A, with mass around 0.06 solar masses, is a brown dwarf or low-mass red dwarf. The secondary, UScoCTIO 108B, with a mass around the deuterium burning limit of 13 Jupiter masses, would be classified as either a brown dwarf or an extrasolar planet.
1RXS J160929.1−210524 is a pre-main-sequence star approximately 450 light-years away in the constellation of Scorpius.
An exocomet, or extrasolar comet, is a comet outside the Solar System, which includes rogue comets and comets that orbit stars other than the Sun. The first exocomets were detected in 1987 around Beta Pictoris, a very young A-type main-sequence star. There are now a total of 27 stars around which exocomets have been observed or suspected.
N Scorpii, also known as HD 148703, is a solitary, bluish-white hued star located in the southern constellation Scorpius. It has an apparent magnitude of 4.23, making it readily visible to the naked eye. N Scorpii was initially given the Bayer designation Alpha Normae by Lacaille but it was later moved from Norma to Scorpius. N Scorpii is currently located 550 light years away based on parallax measurements from the Hipparcos satellite and is part of the Upper Scorpius–Centaurus region of the Scorpius–Centaurus association.
HD 146624 is a single, white-hued star in the southern zodiac constellation of Scorpius. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.80. The distance to HD 146624 can be estimated from its annual parallax shift of 23.0 mas, yielding a separation of 142 light years. At that distance, the visual magnitude is reduced by an extinction of 0.17 due to interstellar dust. It is a member of the Beta Pictoris moving group, a set of ~12 million year old stars that share a common motion through space.
HD 115600 is a star in the constellation Centaurus and a member of the Scorpius–Centaurus association, the nearest OB association to the Sun and the host star of a bright Kuiper belt-like debris ring.
