NGC 1232
Encyclopedia
Intermediate spiral galaxy
An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy. It is designated as SAB in the galaxy morphological classification scheme.-Grades:...
about 60 million 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....
Eridanus
Eridanus (constellation)
Eridanus is a constellation. It is represented as a river; its name is the Ancient Greek name for the Po River. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is the sixth largest of the modern...
.
It is dominated by millions of bright stars and dark dust, in spiral arms rotating about the center. Open cluster
Open cluster
An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist...
s containing bright blue star
Blue star
A blue star is a type of star.Blue star or bluestar may also refer to:The Blue Star Is Kind Of Shiny It Is All Of Stars To Protect The Moon-Music:* Bluestar Entertainment, record label* "Blue Star" , first recorded 1955...
s are sprinkled along these spiral arms, with dark lanes of dense interstellar dust between. Less visible are dim normal stars and interstellar gas, producing such high mass that they dominate the dynamics of the inner galaxy. Not visible is matter of unknown form called dark matter
Dark matter
In astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...
, needed to explain the motions of the visible material in the outer galaxy.
NGC 1232 and its satellite are part of the Eridanus cluster
Eridanus Cluster
The center of the Eridanus Cluster is roughly 85 million light years from Earth, and contains about 73 main galaxies. It is located in the constellation Eridanus near the Fornax cluster, and is sometimes called the "Fornax II cluster."-Table of galaxies:...
of galaxies, along with NGC 1300
NGC 1300
NGC 1300 is a barred spiral galaxy about 61 million light-years away in the constellation Eridanus. The galaxy is about 110,000 light-years across; just slightly larger than our own galaxy, the Milky Way. It may be part of the Eridanus Cluster...
.
NGC 1232A
NGC 1232A is a satellite galaxySatellite galaxy
A satellite galaxy orbits a larger galaxy due to gravitational attraction. Although a galaxy is made of a large number of objects which are not connected to each other, it has a center of mass, which represents a weighted average of the positions of each component object...
of NGC 1232. It is thought to be the cause of unusual bending in the spiral arms. In 1988, NGC 1232A was estimated to be 68 million light-years away while NGC 1232 was estimated to be 65 million light-years away.