Messier 90 (also known as M90 and NGC 4569) is an

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 system devised by Gerard de Vaucouleur ...

exhibiting a weak inner ring structure about 60 million

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Virgo Virgo may refer to: *Virgo (astrology), the sixth astrological sign of the zodiac *Virgo (constellation), a constellation *Virgo Cluster, a cluster of galaxies in the constellation Virgo *Virgo Stellar Stream, remains of a dwarf galaxy *Virgo Supe ...

. It was discovered by

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects''. Messier's purpose f ...

in 1781.

Membership of the Virgo Cluster

Messier 90 is a member of the

Virgo Cluster The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the lar ...

, being one of its largest and brightest spiral galaxies, with an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of around −22 (brighter than the

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...

). The galaxy is found about 1.5° from the central subgroup of

Messier 87 Messier 87 (also known as Virgo A or NGC 4486, generally abbreviated to M87) is a supergiant elliptical galaxy with several trillion stars in the constellation Virgo. One of the largest and most massive galaxies in the local uni ...

. Due to the galaxy's interaction with the

intracluster medium In astronomy, the intracluster medium (ICM) is the superheated plasma that permeates a galaxy cluster. The gas consists mainly of ionized hydrogen and helium and accounts for most of the baryonic material in galaxy clusters. The ICM is heated to t ...

in its cluster, the galaxy has lost much of its

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

. As a result of this process, which is referred to as

ram-pressure stripping Ram pressure is a pressure exerted on a body moving through a fluid medium, caused by relative bulk motion of the fluid rather than random thermal motion. It causes a drag force to be exerted on the body. Ram pressure is given in tensor form as ...

, the medium and

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

regions appear severely truncated compared to similar galaxies outside the Virgo Cluster and there are even

H II region An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. It is typically in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds ...

s outside the

galactic plane The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms ''galactic plane'' and ''galactic poles'' usuall ...

, as well as long (up to 80,000-

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

—that is, 260,000-light-year) tails of ionized gas that has been stripped away.

Star formation activity

As stated above, the

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

in Messier 90 appears truncated. Consequently, the galaxy's spiral arms appear to be smooth and featureless, rather than knotted like galaxies with extended star formation, which justifies why this galaxy, along with

NGC 4921 NGC 4921 is a barred spiral galaxy in the Coma Cluster, located in the constellation Coma Berenices. It is about 320 million light-years from Earth. The galaxy has a nucleus with a bar structure that is surrounded by a distinct ring of dust th ...

in the

Coma Cluster The Coma Cluster (Abell 1656) is a large galaxy cluster, cluster of galaxies that contains over 1,000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. It is loc ...

has been classified as the prototype of an

anemic galaxy An anemic galaxy is a type of spiral galaxy characterized by a low contrast between its spiral arms and its disk. Etymology The term was coined in 1976 by the Canadian astronomer Sidney van den Bergh to classify galaxies that are an interm ...

. Some authors go even further and consider it is a passive spiral galaxy, similar to those found on galaxy clusters with high

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in f ...

. However, its center appears to host significant nebula and star formation, where around 50,000 stars of spectral types O and B that formed around 5 to 6 million years ago are set amidst many A-type

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spa ...

s that were born in earlier starbursts, between 15 and 30 million years ago. Multiple

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

e (up to 100,000) in the nucleus have produced 'superwinds' that are blowing the galaxy's interstellar medium outward into the

collimated in two jets, one of which is being disturbed by interaction with Virgo's intracluster medium as the galaxy moves through it.

Blueshift

The

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors i ...

of Messier 90 is

blueshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in fr ...

ed, which indicates that, net of non-aligned vectors of motion, the gap between it and our galaxy is narrowing. The spectra of most galaxies are

ed. The blueshift was originally used to argue that Messier 90 was actually an object in the foreground of the Virgo Cluster. However, since the phenomenon was limited mostly to galaxies in the same part of the sky as the Virgo Cluster, it appeared that this inference based on the blueshift was incorrect. Instead, many blueshifts exhibit the large range in velocities of objects within the Virgo Cluster.

Distance measurements

Low levels of H I gas prevents using the

Tully–Fisher relation In astronomy, the Tully–Fisher relation (TFR) is an empirical relationship between the mass or intrinsic luminosity of a spiral galaxy and its asymptotic rotation velocity or emission line width. It was first published in 1977 by astronomer ...

to estimate the distance to Messier 90.

Companion galaxies

Messier 90 is rich in

globular cluster A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

s, with around 1,000 of them. The galaxy IC 3583 was once thought to be a

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

of Messier 90; however, it is now thought they are too far away to be

interacting Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interactions o ...

at all.

Gallery

Messier90 - SDSS DR14 (panorama).jpg, Messier 90 imaged by the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

Messier90 - GALEX.jpg , Messier 90 imaged by

GALEX Galaxy Evolution Explorer (GALEX or Explorer 83 or SMEX-7) was a NASA orbiting space telescope designed to observe the universe in ultraviolet wavelengths to measure the history of star formation in the universe. In addition to paving the way ...

Notes

uses a
Hubble constant Hubble's law, also known as the Hubble–Lemaître law, is the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance. In other words, the farther they are, the faster they are moving ...
of 75 (km/s)/Mpc to estimate a distance of 16.8 Mpc to NGC 4569. Adjusting for the 2006 value of 70 (km/s)/Mpc we get a distance of 18.0 Mpc.

References

External links

SEDS: Spiral Galaxy M90
* {{DEFAULTSORT:Messier 090 Intermediate spiral galaxies Virgo Cluster Virgo (constellation) 090 NGC objects 07786 42089 076 Astronomical objects discovered in 1781 Discoveries by Charles Messier