Triangulum Galaxy

== Overview ==
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years from Earth in the constellation Triangulum(2.81 Mly in Space Engine). It is catalogued as Messier 33 or NGC 598 (In version 0.990, the Triangulum galaxy has the code 1237). With the D25 isophotal diameter of 18.74 kiloparsecs or 61,100 light-years(59.310 light-years in Space Engine), the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way.
The galaxy is the smallest spiral galaxy in the Local Group (although the smaller Large and Small Magellanic Clouds may have been spirals before their encounters with the Milky Way), and is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky.
== Relationship with the Andromeda Galaxy ==
M33 is linked to M31 by several streams of neutral hydrogen and stars, which suggests that a past interaction between these two galaxies took place from 2 to 8 billion years ago, and a more violent encounter will occur 2.5 billion years in the future.
The fate of M33 was uncertain in 2009 beyond seeming to be linked to its larger neighbor M31. Suggested scenarios include being torn apart and absorbed by the greater companion, fueling the latter with hydrogen to form new stars; eventually exhausting all of its gas, and thus the ability to form new stars; or participating in the collision between the Milky Way and M31, likely ending up orbiting the merger product and fusing with it much later. Two other possibilities are a collision with the Milky Way before the Andromeda Galaxy arrives or an ejection out of the Local Group. Astrometric data from Gaia appears in 2019 to rule out the possibility that M33 and M31 are in orbit. If correct, M33 is on its first infall proper into the Andromeda Galaxy (M31).
Category:Real objects
Category:Objects
Category:Galaxies