Hyades (star cluster)

HyadesHyades clusterHyades star clusterHyades open clustercluster of stars, the HyadesCollinder 50Hyades superclusterMel 25starsThe Hyades
The Hyades (Greek Ὑάδες, also known as Caldwell 41, Melotte 25, or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.wikipedia
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Caldwell catalogue

CaldwellCaldwell objectCaldwell 106
The Hyades (Greek Ὑάδες, also known as Caldwell 41, Melotte 25, or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
While the Messier catalogue is used by amateur astronomers as a list of deep-sky objects for observation, Moore noted that Messier's list was not compiled for that purpose and excluded many of the sky's brightest deep-sky objects, such as the Hyades, the Double Cluster (NGC 869 and NGC 884), and the Sculptor Galaxy (NGC 253).

Open cluster

open star clusterstar clusteropen clusters
The Hyades (Greek Ὑάδες, also known as Caldwell 41, Melotte 25, or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
A number of open clusters, such as the Pleiades, Hyades or the Alpha Persei Cluster are visible with the naked eye.

Star cluster

star clustersclusterC
The Hyades (Greek Ὑάδες, also known as Caldwell 41, Melotte 25, or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.
Star clusters visible to the naked eye include the Pleiades (M45), Hyades, and the Beehive Cluster (M44).

Taurus (constellation)

TaurusTaurus constellationToro
From the perspective of observers on Earth, the Hyades Cluster appears in the constellation Taurus, where its brightest stars form a "V" shape along with the still-brighter Aldebaran.
Taurus hosts two of the nearest open clusters to Earth, the Pleiades and the Hyades, both of which are visible to the naked eye.

Constellation

constellationsEuropean constellationModern constellation
From the perspective of observers on Earth, the Hyades Cluster appears in the constellation Taurus, where its brightest stars form a "V" shape along with the still-brighter Aldebaran.
Examples of asterisms include the Pleiades and Hyades within the constellation Taurus and the False Cross split between the southern constellations Carina and Vela, or Venus' Mirror in the constellation of Orion.

Aldebaran

Alpha Tauribrightest starRohini
From the perspective of observers on Earth, the Hyades Cluster appears in the constellation Taurus, where its brightest stars form a "V" shape along with the still-brighter Aldebaran.
The star is, by chance, in the line of sight between the Earth and the Hyades, so it has the appearance of being the brightest member of the open cluster, but the cluster that forms the bull's-head-shaped asterism is more than twice as far away, at about 150 light years.

Theta Tauri

θ 2 Tauθ 2 Tauriθ 2 Tauri Aa
Four of these stars, with Bayer designations Gamma, Delta 1, Epsilon, and Theta Tauri, form an asterism that is traditionally identified as the head of Taurus the Bull.
Theta Tauri (θ Tauri, abbreviated Theta Tau, θ Tau) is a wide double star in the constellation of Taurus and a member of the Hyades open cluster.

Gamma Tauri

γ Tauγ TauriGamma
Four of these stars, with Bayer designations Gamma, Delta 1, Epsilon, and Theta Tauri, form an asterism that is traditionally identified as the head of Taurus the Bull.
is a member of, and located within about 2.5 parsecs of the center of, the Hyades star cluster, the nearest open cluster to the Sun.

Epsilon Tauri

ε TauAinε Tauri
Four of these stars, with Bayer designations Gamma, Delta 1, Epsilon, and Theta Tauri, form an asterism that is traditionally identified as the head of Taurus the Bull.
It is a member of the Hyades open cluster.

Asterism (astronomy)

asterismasterismsFalse Cross
Four of these stars, with Bayer designations Gamma, Delta 1, Epsilon, and Theta Tauri, form an asterism that is traditionally identified as the head of Taurus the Bull.
e.g. Both the open clusters The Pleiades or Seven Sisters and The Hyades in Taurus are sometimes considered asterisms, but this depends on the source.

Delta Tauri

Delta 1δ 1 Tauδ 3 Tau
Four of these stars, with Bayer designations Gamma, Delta 1, Epsilon, and Theta Tauri, form an asterism that is traditionally identified as the head of Taurus the Bull.
They are all members of the Hyades star cluster.

Collinder catalog

CollinderCollinder 121Cl
The Hyades (Greek Ὑάδες, also known as Caldwell 41, Melotte 25, or Collinder 50) is the nearest open cluster and one of the best-studied star clusters.

Cosmic distance ladder

standard candlestandard candlesdistance
The fact that three independent measurements agree makes the Hyades an important rung on the cosmic distance ladder method for estimating the distances of extragalactic objects.
In particular the distance obtained for the Hyades has historically been an important step in the distance ladder.

Hyades Stream

Hyades SuperclusterHyades groupHyades moving group
Another associate is the Hyades Stream, a large collection of scattered stars that also share a similar trajectory with the Hyades Cluster.
The Hyades Stream (or Hyades moving group) is a large collection of scattered stars that also share a similar trajectory with the Hyades Cluster.

Hertzsprung–Russell diagram

Hertzsprung-Russell diagramHR diagramcolor-magnitude diagram
An alternative method of computing the distance is to fit the cluster members to a standardized infrared color–magnitude diagram for stars of their type, and use the resulting data to infer their intrinsic brightness.
Russell's early (1913) versions of the diagram included Maury's giant stars identified by Hertzsprung, those nearby stars with parallaxes measured at the time, stars from the Hyades (a nearby open cluster), and several moving groups, for which the moving cluster method could be used to derive distances and thereby obtain absolute magnitudes for those stars.

Metallicity

metalmetal-richmetal-poor
The stars of the Hyades are more enriched in heavier elements than our Sun and other ordinary stars in the Solar neighborhood, with the overall cluster metallicity measured at +0.14.
The UV excess, δ(U−B), is defined as the difference between a star's U and B band magnitudes, compared to the difference between U and B band magnitudes of metal-rich stars in the Hyades cluster.

Beehive Cluster

PraesepeM44NGC 2632
Its age, metallicity, and proper motion coincide with those of the larger and more distant Praesepe Cluster, and the trajectories of both clusters can be traced back to the same region of space, indicating a common origin. It therefore lacks a Messier number, unlike many other, more distant open clusters – e.g., M44 (Praesepe), M45 (Pleiades), and M67.
Age and proper motion coincide with those of the Hyades, suggesting they may share similar origins.

Pleiades

Pleiades star clusterThe PleiadesPleiades cluster
The Hyades are unrelated to two other nearby stellar groups, the Pleiades and the Ursa Major Stream, which are easily visible to the naked eye under clear dark skies. It therefore lacks a Messier number, unlike many other, more distant open clusters – e.g., M44 (Praesepe), M45 (Pleiades), and M67.
Yet some authors argue that the controversy over the distance to the Pleiades discussed below is a red herring, since the cosmic distance ladder can (presently) rely on a suite of other nearby clusters where consensus exists regarding the distances as established by the Hipparcos satellite and independent means (e.g., the Hyades, Coma Berenices cluster, etc.).

Green Grow the Rushes, O

Come And I Will Sing YouGreen Grow the Rashes, OGreen Grow the Rushes
In England the cluster was known as the "April Rainers" from an association with April showers, as recorded in the folk song "Green Grow the Rushes, O".
The April rainers refer to the Hyades star cluster, called the "rainy Hyades" in classical times, and rising with the sun in April; the Greeks thought of the Hyades as inaugurating the April rains.

Hipparcos

HIPHipparcos CatalogueHipparcos satellite
This measurement has been performed with great accuracy using the Hipparcos satellite and the Hubble Space Telescope.

Hyades (mythology)

HyadesEudora
In Greek mythology, the Hyades were the five daughters of Atlas and half-sisters to the Pleiades.
They were changed into a cluster of stars, the Hyades, set in the head of Taurus.

Iota Horologii

ι Hor
Among the remaining members of the Hyades Stream, the exoplanet host star Iota Horologii has recently been proposed as an escaped member of the primordial Hyades Cluster.
Spectrographic analysis indicates the star must have formed together with the stars of the Hyades cluster (~625 million years ago) but must have slowly drifted away, being presently more than 130 light-years away from its original birthplace.

Kappa Tauri

κ 1 κ 1 Tau67 Tau
Kappa Tauri (κ Tau, κ Tauri) is a double star in the constellation Taurus, the two components κ 1 Tauri and κ 2 Tauri both members of the Hyades open cluster.

Messier 67

M67Open Cluster M672682
It therefore lacks a Messier number, unlike many other, more distant open clusters – e.g., M44 (Praesepe), M45 (Pleiades), and M67.
M67 is probably the second best observed open cluster after the Hyades cluster, which is amongst the nearest open clusters and younger than M67.

Upsilon Tauri

υ Tauυ
Upsilon Tauri (υ Tauri) is a solitary, white-hued star in the zodiac constellation of Taurus, and is a member of the Hyades star cluster.