Stellar stream - AbsoluteAstronomy.com

This is a list of stellar streams. A stellar stream is an association of star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

s orbiting a galaxy

Galaxy

A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...

that was once a globular cluster

Globular cluster

A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...

or dwarf galaxy

Dwarf galaxy

A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars...

that has now been torn apart and stretched out along its orbit by tidal forces. An exoplanet has recently been found orbiting a star HIP 13044

HIP 13044

HIP 13044 is a red horizontal branch star about 2,300 light years away from the Earth in the constellation Fornax. The star is part of the Helmi stream, a former dwarf galaxy that merged with the Milky Way between six and nine billion years ago. As a result, HIP 13044 circles the galactic center...

in the Helmi stream

Helmi stream

The Helmi stream is a stellar stream of the Milky Way Galaxy. It started as a dwarf galaxy, now absorbed by the Milky Way as a stream. It was discovered in 1999, is formed of old stars deficient in heavy elements and has a mass of 10 to 100 million solar masses...

Milky Way Galaxy streams

Known streams in the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
Name	Origin	Mass (Solar mass Solar mass The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies... es)	Length (light years)	Composition	Discovery year
Arcturus stream Arcturus stream In astronomy, the Arcturus Stream is a stellar stream which includes the nearby bright star Arcturus. It comprises many stars which share similar proper motion and so are physically associated....	Defunct dwarf galaxy	Unknown	Unknown	Old stars deficient in heavy elements	1971
Magellanic Stream Magellanic Stream The Magellanic Stream is a high-velocity cloud of gas connecting the Large and the Small Magellanic Clouds. It came into existence by a near-collision of both galaxies some 2.5 billion years ago.-Discovery and early observations:...	Large Large Magellanic Cloud The Large Magellanic Cloud is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs , the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal and Canis Major Dwarf Galaxy lying closer to the center... and Small Small Magellanic Cloud The Small Magellanic Cloud is a dwarf galaxy. It has a diameter of about 7,000 light-years and contains several hundred million stars. It has a total mass of approximately 7 billion times the mass of our Sun.... Magellanic Clouds Magellanic Clouds The two Magellanic Clouds are irregular dwarf galaxies visible in the southern hemisphere, which are members of our Local Group and are orbiting our Milky Way galaxy...	200 million	1 million	Hydrogen gas	1972
Sagittarius stream	Sagittarius Dwarf Elliptical Galaxy Sagittarius Dwarf Elliptical Galaxy The Sagittarius Dwarf Elliptical Galaxy is an elliptical loop-shaped satellite galaxy of the Milky Way Galaxy. It consists of four globular clusters, the main cluster being discovered in 1994...	100 million	1 million	Wide variety of stars	1994
Helmi stream Helmi stream The Helmi stream is a stellar stream of the Milky Way Galaxy. It started as a dwarf galaxy, now absorbed by the Milky Way as a stream. It was discovered in 1999, is formed of old stars deficient in heavy elements and has a mass of 10 to 100 million solar masses...	Defunct dwarf galaxy	10 to 100 million	Several complete loops around the Milky Way	Old stars deficient in heavy elements	1999
Palomar 5 stream	Globular cluster Palomar 5 Palomar 5 Palomar 5 is a globular cluster discovered by Walter Baade in 1950. It was independently found again by Albert George Wilson in 1955. After the initial name of Serpens, it was subsequently catalogued as Palomar 5....	5,000	30,000	Old stars	2001
Virgo stream	Defunct dwarf galaxy		30,000		2001
Monoceros ring Monoceros Ring The Monoceros Ring is a ring of stars around the Milky Way which is proposed to consist of a stellar stream torn from the Canis Major Dwarf Galaxy as it merges with the Milky Way over the course of billions of years...	Canis Major dwarf galaxy Canis Major Dwarf Galaxy The Canis Major Dwarf Galaxy is located in the same part of the sky as the constellation Canis Major. The galaxy contains a relatively high percentage of red giant stars, and is thought to contain an estimated one billion stars in all....	100 million	200,000	Intermediate-age stars	2002
Anticenter stream	Defunct dwarf galaxy	Unknown	30,000	Old stars	2006
NGC 5466 stream 45 Degree Tidal Stream	Globular cluster NGC 5466 NGC 5466 NGC 5466 is a class XII globular cluster in the constellation Boötes. Located 51,800 light years from Earth and 52,800 light years from the Galactic center, it was discovered by William Herschel on May 17, 1784, as H VI.9...	10,000	60,000	Very old stars	2006
Orphan stream	Ursa Major II Dwarf Ursa Major II Dwarf Ursa Major II or Uma II is a dwarf spheroidal galaxy situated in the Ursa Major constellation and discovered in 2006 in the data obtained by Sloan Digital Sky Survey. The galaxy is located approximately 30 kpc from the Sun and moves towards the Sun with the velocity of about 116 km/s... galaxy	100,000	20,000	Old stars	2006
Acheron stream	Globular cluster Globular cluster A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...				2007
Cocytus stream	Globular cluster				2007
Lethe stream	Globular cluster				2007
Styx stream	Defunct dwarf galaxy				2007
Bootes III stream	Embedded in, & possible progenitor of Styx stream				2007
Aquarius Stream Aquarius Stream The Aquarius Stream is a stellar stream located in the Milky Way Galaxy. It is so named because most of the stars in the stream lie in the direction of the Aquarius constellation. At its nearest point it is about 2000 light years from Earth; At its farthest it is about 30,000 light years away...	Defunct dwarf galaxy Dwarf galaxy A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Way's 200-400 billion stars...	Unknown	30,000	Old stars	2010

Andromeda Galaxy streams

Known streams in the Andromeda Galaxy
Andromeda Galaxy
The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...
Name	Origin	Mass (Solar mass Solar mass The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies... es)	Length (light years)	Composition	Discovery year
M31 Giant stellar stream
Andromeda NE stellar stream					2004
Tidal Stream Northwest (Tidal Stream E and F)					2009
Tidal Stream Southwest					2009

Streams beyond the Local Group

Other known streams outside the Local Group
Local Group
The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...
Name	Location	Origin	Characteristics	Discovery year
Young Blue Tidal Stream	NGC 5128	A gas fragment or a dwarf galaxy		2002
	NGC 4013 NGC 4013 NGC 4013 is an edge-on barred spiral galaxy about 55 million light-years away in the constellation Ursa Major. The disk of NGC 4013 shows a distinct "peanut"-shaped bulge in long exposure photographs that N-body computer simulations suggest is consistent with a stellar bar seen perpendicular to...	former dwarf satellite with low inclination orbit	large looping structure	2008
	NGC 5907 NGC 5907 NGC 5907 is a spiral galaxy located approximately 50 million light years from Earth. It has an anomalously low metallicity and few detectable giant stars, being apparently composed almost entirely of dwarf stars.It is a member of the NGC 5866 Group....	low-mass satellite accretion	multiple surrounding loops	2009
	NGC 4651	satellite accretion	narrow jet-like structure and surrounding debris shell	2010
	NGC 1055 NGC 1055 NGC 1055 is an edge-on spiral galaxy located in the constellation Cetus that has a prominent nuclear bulge crossed by a wide, knotty, dark lane of dust and gas. The spiral arm structure appears to be elevated above the galaxy's plane and obscures the upper half of the bulge...	satellite accretion	box shaped halo pierced by multiple spikes	2010
	NGC 3521 NGC 3521 NGC 3521 is a type SABbc spiral galaxy 35 million light-years away from Earth....	satellite accretion	jet-like structure and surrounding debris shell	2010
	NGC 7531	satellite accretion	surrounding debris shell	2010
	NGC 1084	satellite accretion	three giant disconnected plumes of similar width	2010
	NGC 4216 NGC 4216 NGC 4216 is a metal-rich intermediate spiral galaxy located not far from the center of the Virgo Cluster of galaxies, roughly 40 million light-years away....	satellite accretion	ongoing tidal disruption of satellite galaxies seen as long tails extending from the progenitor satellite	2010
	NGC 1055 NGC 1055 NGC 1055 is an edge-on spiral galaxy located in the constellation Cetus that has a prominent nuclear bulge crossed by a wide, knotty, dark lane of dust and gas. The spiral arm structure appears to be elevated above the galaxy's plane and obscures the upper half of the bulge...	satellite accretion	clear box shaped inner halo sprinkled with a plethora of coherent spikes	2010

Milky Way Galaxy streams

Andromeda Galaxy streams

Streams beyond the Local Group

External links

See also