Messier 82
Adapted from Wikipedia · Discoverer experience
Messier 82, also known as the Cigar Galaxy, is a bright and active galaxy located about 12 million light-years away in the constellation Ursa Major. It is one of the closest examples of a starburst galaxy, where new stars are forming at an incredibly fast rate. This intense star formation is thought to be caused by gravitational interactions with its neighbor, the galaxy M81.
Because of its closeness and brightness, Messier 82 has been studied extensively by astronomers. In January 2014, a Type Ia supernova named SN 2014J was discovered there, giving scientists a rare chance to observe such an event up close. Scientists have also found powerful objects within Messier 82, including the brightest pulsar ever known and, in November 2023, the first gamma-ray burst from a magnetar detected outside our own Milky Way galaxy. These discoveries help us understand the dramatic processes happening in active galaxies.
Discovery
M82, along with M81, was discovered by Johann Elert Bode in 1774. He described it as a "nebulous patch" that was very pale and had an elongated shape. Later in 1779, Pierre Méchain found both objects again and told Charles Messier, who then added them to his catalog.
Structure
Messier 82, also called M82, was once thought to be an irregular galaxy, but in 2005, two symmetric spiral arms were found in near-infrared images. These arms were hidden before because of the galaxy's bright disk, edge-on view, and dusty filaments.
The center of M82 is a busy place where new stars are forming much faster than in our Milky Way. In 2005, the Hubble Space Telescope found many young star clusters here. The galaxy also has a supermassive black hole at its center, and in 2010, astronomers observed a strange object sending out radio waves unlike anything seen before. Scientists are still trying to understand what this object might be.
Starbursts
Messier 82, also called M82, is being affected by its larger neighbor, the spiral M81. The pull of gravity has changed the shape of M82, starting about 100 million years ago. This has made lots of new stars form, about ten times more than in normal galaxies.
M82 and M81 have come close to each other before, sending gas into M82's center. The last time this happened was about 200 million to 500 million years ago, causing a big burst of new stars. This burst lasted for about 50 million years. After that, two more bursts of star formation happened, with the last one ending about 4 million to 6 million years ago. The stars in M82’s disk formed in a burst about 500 million years ago and stopped forming about 100 million years ago, except for a small amount in its outer areas.
Supernovae
Messier 82 is a galaxy where many bright stars are born and sometimes explode, known as supernovae. These explosions happen when very large stars reach the end of their lives. The first time scientists saw a supernova in this galaxy was in 2004, called SN 2004am. Another possible supernova was spotted in 2008, but it was hard to see because of thick dust in the galaxy.
In January 2014, a very bright supernova named SN 2014J was discovered. It became bright enough that people with telescopes could see it. This was a special kind of supernova called a Type Ia, and it was one of the closest such events seen in many years.
Main article: SN 2014J
Images
This article is a child-friendly adaptation of the Wikipedia article on Messier 82, available under CC BY-SA 4.0.
Images from Wikimedia Commons. Tap any image to view credits and license.
Safekipedia