The Taurus Constellation

Taurus (Latin for “the Bull”) is one of the constellations of the zodiac, which means it is crossed by the plane of the ecliptic. Taurus is a large and prominent constellation in the northern hemisphere’s winter sky. It is one of the oldest constellations, dating back to at least the Early Bronze Age when it marked the location of the Sun during the spring equinox. Taurus lies between Aries to the west and Gemini to the east; to the north lies Perseus and Auriga, to the southeast Orion, to the south Eridanus, and to the southwest Cetus. In September and October, Taurus is visible in the evening along the eastern horizon. The most favourable time to observe Taurus in the night sky is during the months of December and January. By March and April, the constellation will appear to the west during the evening twilight. The galactic plane of the Milky Way intersects the northeast corner of the constellation and the galactic anticentre is located near the border between Taurus and Auriga. Taurus is the only constellation crossed by all three of the galactic equator, celestial equator, and ecliptic. A ring-like galactic structure known as Gould’s Belt passes through the constellation. The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of 26 segments. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 03h 23.4m and  05h 53.3m, while the declination coordinates are between 31.10° and −1.35°.

The brightest member of this constellation is Aldebaran, an orange-hued, spectral class K5 III giant star. Its name derives from Arabic for “the follower,” probably from the fact that it follows the Pleiades during the nightly motion of the celestial sphere across the sky. Forming the profile of a Bull’s face is a V or K-shaped asterism of stars. This outline is created by prominent members of the Hyades, the nearest distinct open star cluster after the Ursa Major Moving Group. In this profile, Aldebaran forms the bull’s bloodshot eye, which has been described as “glaring menacingly at the hunter Orion,” a constellation that lies just to the southwest. It includes a double star, Theta Tauri (the proper name of Theta2 Tauri is Chakumuy). To the west, the two horns of the bull are formed by Beta (β) Tauri and Zeta (ζ) Tauri; two star systems that are separated by 8°. Beta is a white, spectral class B7 III giant star known as El Nath, which comes from the Arabic phrase “the butting”, as in butting by the horns of the bull. At magnitude 1.65, it is the second brightest star in the constellation. The star Lambda (λ) Tauri is an eclipsing binary star. This system consists of a spectral class B3 star being orbited by a less massive class A4 star. The plane of their orbit lies almost along the line of sight to the Earth. Every 3.953 days the system temporarily decreases in brightness by 1.1 magnitudes as the brighter star is partially eclipsed by the dimmer companion. 

In the north-eastern quadrant of the Taurus constellation lie the Pleiades (M45), one of the best known open clusters. The seven most prominent stars in this cluster are at least visual magnitude six, and so the cluster is also named the “Seven Sisters.” Astronomers estimate that the cluster has approximately 500-1,000 stars, all of which are around 100 million years old. The Pleiades themselves are represented by large, bright stars; also many small brown dwarfs and white dwarfs exist. The cluster is estimated to dissipate in another 250 million years. In the northern part of the constellation to the northwest of the Pleiades lies the Crystal Ball Nebula, known by its catalogue designation of NGC 1514. This planetary nebula is of historical interest following its discovery by German-born English astronomer William Herschel in 1790. In 1864, English astronomer William Huggins used the spectrum of this nebula to deduce that the nebula is a luminous gas, rather than stars. The Maia Nebula is a bright reflection nebula found in the Pleiades cluster. The nebula has the designation NGC 1432 in the New General Catalogue. It occupies an area about 1.6 by 1.4 light years across. The Merope Nebula is a faint reflection nebula and suspected supernova remnant located in the Pleiades cluster. The nebula surrounds the star Merope (23 Tauri), after which it gets its name. It has the designation NGC 1435 in the New General Catalogue. A degree to the northwest of ζ Tauri is the Crab Nebula (M1), a supernova remnant. This expanding nebula was created by a Type II supernova explosion, which was seen from Earth on July 4, 1054. At its peak, the supernova reached magnitude −4, but the nebula is currently magnitude 8.4 and requires a telescope to observe. North American peoples also observed the supernova, as evidenced from a painting on a New Mexican canyon and various pieces of pottery that depict the event. However, the remnant itself was not discovered until 1731, when John Bevis found it. The Hyades is an open cluster that contains hundreds of stars that share the same motion through space, origin, age, and chemical content. It is the nearest open star cluster to the Sun, and consequently the most studied one, too. Its estimated age is about 625 million years. The brightest stars in the Hyades Cluster and Aldebaran, the brightest star in the Taurus constellation, form a V shape. Aldebaran is not a member of the cluster, but lies along the same line of sight. The Hyades Cluster has an apparent magnitude of 0.5 and is about 153 light years distant. The core of the cluster, densely populated with stars, has a diameter of 17.6 light years. NGC 1409 and NGC 1410 are a set of colliding galaxies in Taurus constellation. The two are connected by a pipeline of gas spanning over 20,000 light years that is being funnelled from one galaxy to the other. As a result, there is a lot of star forming activity occurring in NGC 1410, the galaxy that is on the receiving end. NGC 1409, on the other hand, is devoid of young blue stars. The pair has an apparent magnitude of 15.4 and is 300 million light years distant from the Sun. The galaxies are gravitationally bound and will eventually merge into one.

During November, the Taurid meteor shower appears to radiate from the general direction of this constellation. The Beta Taurid meteor shower occurs during the months of June and July in the daytime and is normally observed using radio techniques. Between 18 and 29 October, both the Northern Taurids and the Southern Taurids are active; though the latter stream is stronger. However, between November 1 and 10, the two streams equalize. Credits: Constellation Guide, Wikipedia.