Messier 99
Encyclopedia
Messier 99 is an unbarred spiral galaxy
approximately 50 million
light-year
s away in the constellation
Coma Berenices
.
The galaxy has a normal looking arm and an extended arm that is less tightly wound. A bridge of neutral hydrogen gas links NGC 4254 with VIRGOHI21
. The gravity from the possible dark galaxy
VIRGOHI21
may have distorted M99 and drawn out the gas bridge, as the two galaxy-sized objects have a close encounter, before they go their separate ways. It is expected that the drawn out arm will relax to match the normal arm once the encounter is over. Three supernovae have been observed in this galaxy.
on March 17, 1781 along . The discovery was then reported to Charles Messier
, who included the object in the Messier Catalogue, which was the first astronomical catalogue of star clusters, nebulae, and galaxies.
Messier 99 was one of the first galaxies in which a spiral pattern was first seen. The spiral pattern was first identified by Lord Rosse in the spring of 1846.
Unbarred spiral galaxy
An unbarred spiral galaxy is a type of spiral galaxy without a central bar, or one that is not a barred spiral galaxy. It is designated with an SA in the galaxy morphological classification scheme.The Sombrero Galaxy is an unbarred spiral galaxy....
approximately 50 million
1 E23 m
To help compare different orders of magnitude, this page lists distances starting at 100 Zm .Distances shorter than 100 Zm* 140 Zm — 15 million light years — Distance to Centaurus A galaxy...
light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s 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....
Coma Berenices
Coma Berenices
Coma Berenices is a traditional asterism that has since been defined as one of the 88 modern constellations. It is located near Leo, to which it formerly belonged, and accommodates the North Galactic Pole...
.
The galaxy has a normal looking arm and an extended arm that is less tightly wound. A bridge of neutral hydrogen gas links NGC 4254 with VIRGOHI21
VIRGOHI21
VIRGOHI21 is an extended region of neutral hydrogen in the Virgo cluster discovered in 2005. Analysis of its internal motion indicates that it may contain a large amount of dark matter, as much as a small galaxy. Since VIRGOHI21 apparently contains no stars, this would make it one of the first...
. The gravity from the possible dark galaxy
Dark galaxy
A dark galaxy is a hypothetical galaxy composed of dark matter. Dark galaxies receive their name because they have no detectable stars and are theoretically invisible...
VIRGOHI21
VIRGOHI21
VIRGOHI21 is an extended region of neutral hydrogen in the Virgo cluster discovered in 2005. Analysis of its internal motion indicates that it may contain a large amount of dark matter, as much as a small galaxy. Since VIRGOHI21 apparently contains no stars, this would make it one of the first...
may have distorted M99 and drawn out the gas bridge, as the two galaxy-sized objects have a close encounter, before they go their separate ways. It is expected that the drawn out arm will relax to match the normal arm once the encounter is over. Three supernovae have been observed in this galaxy.
History
Messier 99 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:...
on March 17, 1781 along . The discovery was then reported to 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"...
, who included the object in the Messier Catalogue, which was the first astronomical catalogue of star clusters, nebulae, and galaxies.
Messier 99 was one of the first galaxies in which a spiral pattern was first seen. The spiral pattern was first identified by Lord Rosse in the spring of 1846.
See also
- Messier 83 - a similar face-on spiral galaxy
- Pinwheel GalaxyPinwheel GalaxyThe Pinwheel Galaxy is a face-on spiral galaxy distanced 21 million light-years away in the constellation Ursa Major, first discovered by Pierre Méchain on March 27, 1781, and communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final...
- a similar face-on spiral galaxy