The Hyades Stream (or Hyades
moving group) is a large collection of scattered stars that also share a similar trajectory with the
Hyades Cluster. In 1869,
Richard A. Proctor observed that numerous stars at large distances from the Hyades share a similar motion through space.
In 1908,
Lewis Boss reported almost 25 years of observations to support this premise, arguing for the existence of a co-moving group of stars that he called the Taurus Stream (now generally known as the Hyades Stream or, following
Olin J. Eggen who assumed that it was a vestige of an initially more massive cluster which had partly evaporated, the Hyades Supercluster
). Boss published a chart that traced the scattered stars' movements back to a common point of convergence.
Eggen's argument that groups of this type are in fact cluster remnants has been debated. It has been noted that because such phenomena may also be the result of other dynamical mechanisms. Famaey B, ''et al.'' report that about 85% of stars in the Hyades Stream have been shown to be completely unrelated to the original cluster on the grounds of dissimilar age and
metallicity
In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...
; their common motion is attributed to tidal effects of the massive rotating
bar at the center of the
Milky Way Galaxy
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are ...
.
Among the remaining members of the Hyades Stream, the
exoplanet
An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...
host star
Iota Horologii
Iota Horologii, Latinisation of names, Latinized from ι Horologii, is a star in the Horologium (constellation), Horologium constellation. With an apparent magnitude of +5.40, it can be seen to the naked eye only from places not affecte ...
has recently been proposed as an escaped member of the primordial Hyades Cluster.
[, announced in ]
References
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