Messier 109
Encyclopedia
Messier 109 is a barred spiral galaxy
approximately away in the constellation
Ursa Major
. M109 can be seen southeast of the star Phecda
(γ UMa).
in 1781. In 1783 Charles Messier
catalogued NGC 3992 as his 109th object
.
Between the 1920s through the 1950s, it was considered that Messier objects over 103 were not official, but in later years the additions became more widely accepted. David H. Levy
mentions the modern 110 object catalog while Sir Patrick Moore gave the original to 104 but has M105-M109 listed as an addendum. By the late 1970s all 110 objects are commonly used among astronomers as they still are today.
1956A was observed in M109. SN 1956A was a type Ia supernova
in the southeast part of the galaxy, glowing at magnitude 12.8 to 12.3 at its maximum. SN 1956A has been the only supernova observed in M109 since its discovery.
M109 has three satellite galaxies (UGC 6923, UGC 6940 and UGC 6969) and possibly might have more. Detailed hydrogen line
observations have been obtained from M109 and its satellites. M109's H I distribution
is regular with a low level radial extension outside the stellar disc, while at exactly the region of the bar, there is a central H I hole in the gas distribution. Possibly the gas has been transported inwards by the bar because of the emptiness of the hole no large accretion events can have happened in the recent past.
Ursa Major that may contain over 50 galaxies.
Barred spiral galaxy
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in approximately two-thirds of all spiral galaxies...
approximately away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Ursa Major
Ursa Major
Ursa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...
. M109 can be seen southeast of the star Phecda
Gamma Ursae Majoris
Gamma Ursae Majoris is a star in the constellation Ursa Major. It has the traditional name Phad, or Phecda, from the Arabic phrase فخذ الدب "fakhð ad-dubb" ....
(γ UMa).
History
Messier 109 was discovered by Pierre MéchainPierre Méchain
Pierre François André Méchain was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep sky objects and comets.-Life:...
in 1781. In 1783 Charles Messier
Charles Messier
Charles Messier was a French astronomer most notable for publishing an astronomical catalogue consisting of deep sky objects such as nebulae and star clusters that came to be known as the 110 "Messier objects"...
catalogued NGC 3992 as his 109th object
Messier object
The Messier objects are a set of astronomical objects first listed by French astronomer Charles Messier in 1771. The original motivation of the catalogue was that Messier was a comet hunter, and was frustrated by objects which resembled but were not comets...
.
Between the 1920s through the 1950s, it was considered that Messier objects over 103 were not official, but in later years the additions became more widely accepted. David H. Levy
David H. Levy
David H. Levy is a Canadian astronomer and science writer most famous for his co-discovery in 1993 of Comet Shoemaker–Levy 9, which collided with the planet Jupiter in 1994.-Biography:...
mentions the modern 110 object catalog while Sir Patrick Moore gave the original to 104 but has M105-M109 listed as an addendum. By the late 1970s all 110 objects are commonly used among astronomers as they still are today.
General information
In March of 1956, supernovaSupernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
1956A was observed in M109. SN 1956A was a type Ia supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
in the southeast part of the galaxy, glowing at magnitude 12.8 to 12.3 at its maximum. SN 1956A has been the only supernova observed in M109 since its discovery.
M109 has three satellite galaxies (UGC 6923, UGC 6940 and UGC 6969) and possibly might have more. Detailed hydrogen line
Hydrogen line
The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This electromagnetic radiation is at the precise frequency of 1420.40575177 MHz, which is equivalent to the vacuum...
observations have been obtained from M109 and its satellites. M109's H I distribution
H I region
An H I region is an interstellar cloud composed of neutral atomic hydrogen , in addition to the local abundance of helium and other elements. These regions are non-luminous, save for emission of the 21-cm region spectral line. This line has a very low transition probability, so requires large...
is regular with a low level radial extension outside the stellar disc, while at exactly the region of the bar, there is a central H I hole in the gas distribution. Possibly the gas has been transported inwards by the bar because of the emptiness of the hole no large accretion events can have happened in the recent past.
Environment
M109 is the brightest galaxy in the M109 Group, a large group of galaxies located in the constellationConstellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Ursa Major that may contain over 50 galaxies.