Messier 90 is a member of theVirgo Cluster,[5] being one of its largest and brightest spiral galaxies, with anabsolute magnitude of around −22 (brighter than theAndromeda Galaxy).[6] The galaxy is found about 1.5° from the central subgroup ofMessier 87.[7] Due to the galaxy's interaction with theintracluster medium in its cluster, the galaxy has lost much of itsinterstellar medium. As a result of this process, which is referred to asram-pressure stripping, the medium andstar formation regions appear severely truncated compared to similar galaxies outside the Virgo Cluster[8] and there are evenH II regions outside thegalactic plane,[8] as well as long (up to 80,000-parsec—that is, 260,000-light-year) tails of ionized gas that have been stripped away.[9]
As stated above, thestar formation 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,[8] which justifies why this galaxy, along withNGC 4921 in theComa Cluster has been classified as the prototype of ananemic galaxy.[10] Some authors go even further and consider it is apassive spiral galaxy, similar to those found on galaxy clusters with highredshift.[11]
However, its center appears to hostsignificant nebula and star formation, where around 50,000 stars of spectral typesO andB that formed around 5 to 6 million years ago[12] are set amidst manyA-typesupergiants that were born in earlier starbursts, between 15 and 30 million years ago.[13]
Multiplesupernovae (up to 100,000[13]) in the nucleus have produced 'superwinds' that are blowing the galaxy's interstellar medium outward into theintracluster medium[14] collimated in two jets, one of which is being disturbed by interaction with Virgo's intracluster medium as the galaxy moves through it.[15]
Thespectrum of Messier 90 isblueshifted, which indicates that, net ofnon-aligned vectors of motion, the gap between it and our galaxy is narrowing.[2] The spectra of most galaxies areredshifted. 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.[7]
Messier 90 is rich inglobular clusters, with around 1,000 of them.[6] The galaxyIC 3583 was once thought to be asatellite of Messier 90;[13] however, it is now thought they are too far away to beinteracting at all.[9]
^Tschöke et al. 2001 uses aHubble constant of 75 (km/s)/Mpc to estimate a distance of 16.8 Mpc to NGC 4569. Adjusting for the 2006 value of 70+2.4 −3.2 (km/s)/Mpc we get a distance of 18.0+0.9 −0.6 Mpc.
^B. Binggeli; A. Sandage; G. A. Tammann (1985). "Studies of the Virgo Cluster. II - A catalog of 2096 galaxies in the Virgo Cluster area. V - Luminosity functions of Virgo Cluster galaxies".The Astronomical Journal.90:1681–1759.Bibcode:1985AJ.....90.1681B.doi:10.1086/113874.
^Moran, S. M.; Ellis, R. S.; Smith, G. P.; Rich, R. M.; et al. (2007). "A Wide-Field Survey of Two z ~ 0.5 Galaxy Clusters: Identifying the Physical Processes Responsible for the Observed Transformation of Spirals into S0s".The Astrophysical Journal.671 (2):1503–1522.arXiv:0707.4173.Bibcode:2007ApJ...671.1503M.doi:10.1086/522303.S2CID14325264.
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