Messier 99

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Galaxy in the constellation Coma Berenices

title: "Messier 99" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["unbarred-spiral-galaxies", "virgo-cluster", "coma-berenices", "messier-objects", "ngc-objects", "ugc-objects", "principal-galaxies-catalogue-objects", "astronomical-objects-discovered-in-1781", "discoveries-by-pierre-méchain"] description: "Galaxy in the constellation Coma Berenices" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Messier_99" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Galaxy in the constellation Coma Berenices ::

::data[format=table title="Infobox Galaxy"]

Field	Value
name	Messier 99
image	M99s crop.jpg
caption	Galaxy Messier 99, Schulman Telescope
constellation name	Coma Berenices
epoch	J2000
group_cluster	Virgo Cluster
type	SA(s)c
ra
dec
z	0.008029
h_radial_v
dist_ly	13.87 Mpc
appmag_v	9.9
size_v	5.4 × 4.7
size	98,130 ly (30.10 kpc) (estimated)
names	Coma Pinwheel Galaxy, Virgo Cluster Pinwheel, M99, NGC 4254, PGC 39578, UGC 7345
::

Messier 99 or M99, also known as NGC 4254 or St. Catherine's Wheel, is a grand design spiral galaxy in the northern constellation Coma Berenices approximately 15,000,000 pc from the Milky Way.

This galaxy has a morphological classification of SA(s)c, indicating a pure spiral shape with loosely wound arms. It has a peculiar shape with one normal looking arm and an extended arm that is less tightly wound. The galaxy is inclined by 42° to the line-of-sight with a major axis position angle of 68°.

A bridge of neutral hydrogen gas links NGC 4254 with VIRGOHI21, an HI region and a possible dark galaxy. The gravity from the latter may have distorted M99 and drawn out the gas bridge, as the two galaxy-sized objects may have had a close encounter before parting greatly. However, VIRGOHI21 may instead be tidal debris from an interaction with the lenticular galaxy NGC 4262 some 280 million years ago. It is expected that the drawn out arm will relax to match the normal arm once the encounter is over.

While not classified as a starburst galaxy, M99 has a star formation activity three times larger than other galaxies of similar Hubble type that may have been triggered by the encounter. M99 is likely entering the Virgo Cluster for the first time bound to the periphery of the cluster at a projected separation of 3.7°, or around one megaparsec, from the cluster center at Messier 87. The galaxy is undergoing ram-pressure stripping of much of its interstellar medium as it moves through the intracluster medium.

Supernovae and luminous red nova

Four supernovae have been observed in M99:

SN 1967H (Type II, mag. 14.0) was discovered by Fritz Zwicky on 1 July 1967.
SN 1972Q (type unknown, mag. 15.8) was discovered by Leonida Rosino on 14 December 1972.
SN 1986I (Type II, mag. 14) was discovered by Carlton Pennypacker et al. on 17 May 1986.
SN 2014L (Type Ic, mag. 17.2) was discovered by the THU-NAOC Transient Survey (TNTS) on 26 January 2014.

One luminous red nova has been observed in M99:

PTF 10fqs (Type LRN, mag. 20.1) was discovered by the Palomar Transient Factory on 16 April 2010. NOTOC

References

| last1=de Vaucouleurs | first1=G. | last2=de Vaucouleurs | first2=A. | last3=Corwin | first3=H. G. Jr. | last4=Buta | first4=R. J. | last5=Paturel | first5=G. | last6=Fouque | first6=P. | title=Third reference catalogue of bright galaxies | version=9 | display-authors=1 | date=1991 | publisher=Springer-Verlag | location=New York }}

| last1=Tully | first1=R. Brent | last2=Courtois | first2=Hélène M. | last3=Sorce | first3=Jenny G. | display-authors=1 | title=Cosmicflows-3 | journal=The Astronomical Journal | volume=152 | issue=2 | id=50 | pages=21 | date=August 2016 | doi=10.3847/0004-6256/152/2/50 | bibcode=2016AJ....152...50T | arxiv=1605.01765 | s2cid=250737862 | postscript=. | doi-access=free }}

| first1=K. G. | last1=Jones | date=1991 | edition=2nd | title=Messier's Nebulae and Star Clusters | publisher=Cambridge University Press | isbn=978-0-521-37079-0 }}

| first1=J. L. E. | last1=Dreyer | editor1-first=R. W. | editor1-last=Sinnott | title=The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters | publisher=Sky Publishing Corporation/Cambridge University Press | date=1988 | isbn=978-0-933346-51-2 }}

| title=NASA/IPAC Extragalactic Database | work=Results for NGC 4254 | url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Messier+99&img_stamp=yes | access-date=2006-11-25 }}

| last1=Vollmer | first1=B. | last2=Huchtmeier | first2=W. | last3=van Driel | first3=W. | date=September 2005 | journal=Astronomy and Astrophysics | volume=439 | issue=3 | pages=921–933 | title=NGC 4254: a spiral galaxy entering the Virgo cluster | bibcode = 2005A&A...439..921V | arxiv=astro-ph/0505021 | doi=10.1051/0004-6361:20041350 | s2cid=17414818 }}

| last1=Chyży | first1=K. T. | last2=Ehle | first2=M. | last3=Beck | first3=R. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=415–429 | date=September 2007 | title=Magnetic fields and gas in the cluster-influenced spiral galaxy NGC 4254. I. Radio and X-rays observations | bibcode=2007A&A...474..415C | arxiv=0708.1533 | doi=10.1051/0004-6361:20077497 | s2cid=16273521 }}

| title=A Bright Spark in a Nearby Spiral Galaxy | url=http://www.spacetelescope.org/images/potw1223a/ | access-date=4 June 2012 | newspaper=ESA/Hubble Picture of the Week }} Not in use--

| title=Supernova 1986I in NGC 4254 | last1=Penhallow | first1=W. S. | last2=Wenzel | first2=W. | last3=Jager | first3=A. | last4=Kirshner | first4=R. | last5=Wilson | first5=I. | last6=Horine | first6=E. | last7=Peters | first7=J. | display-authors=1 | journal=IAU Circular | issue=4225 | pages=2 | editor1-last=Marsden | editor1-first=B. G. | date=June 1986 | bibcode=1986IAUC.4225....2P }}

| first1=A. P. | last1=Fairall | title=The spectrum of the type II supernova 1967h in NGC 4254 | journal=Monthly Notes of the Astronomical Society of South Africa | volume=34 | issue=7 | date=August 1975 | pages=94–98 | hdl=10520/AJA00248266_2204 | url = https://journals.co.za/doi/abs/10.10520/AJA00248266_2204}}

References

"The Schulman Telescope".
"Messier 99".
((The Earl of Rosse)). (1850). "Observations on the Nebulae". Philosophical Transactions of the Royal Society of London.
"SN 2014L". [[International Astronomical Union.
(2014). "Supernova 2014L in M99 = PSN J12184868+1424435". Central Bureau Electronic Telegrams.
"SN 1972Q". [[International Astronomical Union.
"SN 1986I". [[International Astronomical Union.
(1986). "Supernovae". IAU Circular.
"SN 1967H". [[International Astronomical Union.
(1968). "The 1967 Palomar Supernova Search". Publications of the Astronomical Society of the Pacific.
"M 99".
(1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal.
(2010). "PTF10fqs: A Luminous Red Nova in the spiral galaxy M99". The Astronomer's Telegram.
(2011). "PTF 10fqs: A Luminous Red Nova in the Spiral Galaxy Messier 99". The Astrophysical Journal.

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