What is the constellation Triangle?
He Triangle It is a small constellation with three stars of the third and fourth magnitude, they form an elongated triangle. It is one of the 88 modern constellations, and also one of the 48 Ptolemaic constellations.
Main stars Triangle
Triangle has no stars of the first magnitude. Its brightest stars are β (magnitude 3.00) and α (magnitude 3.41).
Metallah (α Trianguli)
Metallah (α Trianguli) It is not the brightest star in the constellation, but its position at the top of the triangle (its name means precisely this in Arabic) led Johann Bayer to give it the designation α.
With an apparent magnitude of 3.41, Metallah is a white-yellow sub-giant 64 light years away, 13 times more luminous than the Sun and 1.5 times more massive than it.
Metallah is a double star: its companion, indiscernible with the telescope, revolves around it in just 1.74 days and is only 0.04 au away.
β Triangle
β Triangle, with an apparent magnitude of 3.00, is the brightest star in the Triangulum constellation. It is a sub-giant, 4 times larger than the Sun, 70 times brighter, surrounded by a disk of dust.
It is also a double star, with a companion (similar to the Sun) that orbits at 0.3 au on average in 31.8 days.
γ Triangle
γ Triangle, the third star of the constellation (magnitude 4.03), closes the triangle. It is a white star, about 2 times larger than the Sun, which rotates very quickly, in 12 hours, at least 200 km/s at the equator.
γ Trianguli, δ Trianguli (magnitude 4.84) and 7 Trianguli (magnitude 5.25) apparently very close on the celestial sphere. In reality, δ Trianguli is located 35 light years from our system (therefore very close), γ Trianguli 118 and 7 Trianguli 293. They therefore have nothing to do with each other.
Other stars
δ Trianguli is a double star, its two components are very similar to the Sun. They are separated by only 0.1 au.
ι Trianguli is also a double star, made up of a yellow star and a blue star. Each of these stars is also double.
R Trianguli is a variable star of the Mira (or Ceti) type and oscillates between magnitudes 5.30 and 12.6 with a period of 266.9 days.
Triangle Deep Sky Objects
The constellation of Triangle It contains the spiral galaxy M33, appropriately called the Triangle Galaxy. It is the third largest galaxy in our Local Group, the other two being the Milky Way and the Andromeda Galaxy.
This constellation also contains the nebula NGC 604 (located within M33), the largest region of ionized hydrogen known, with a diameter of 1,500 light years, the open cluster C 0147 + 270, the spiral galaxy NGC 925 and also NGC 672 and IC 1727, two galaxies approximately 18 million light years apart, but separated by only 88,000 light years. Quasar 3C 48, north of the constellation, was one of the first to be discovered.
History and Mythology of the Triangle constellation
One of the first names of the constellation was Sicily, because Ceres, patron goddess of Sicily, prayed to Jupiter to place the island in the heavens.
On the other hand, another French branch tells us that Triangle It already appeared in Ptolemy’s list of 48 constellations in the Almagest, and was one of the rare ancient constellations, with Balance that did not come from a myth and that was described with a geometric figure.
In Greek times, this constellation was named Deltotron, the Delta, probably that of the Nile identified with the Greek letter Δ. The Romans preserved this name under the name Deltotum.