Trifid Nebula

{{short description|Emission nebula in the constellation Sagittarius}}

{{Infobox nebula

| name = Trifid Nebula

| image = M020.jpg

| caption =

| credit = NASA/ESA

| type = H II region

| type2 = reflection nebula and dark nebula

| epoch = J2000

| ra = {{RA|18|02|23}}{{cite simbad |title=NGC 6514 |access-date=2006-11-16}}

| dec = {{DEC|-23|01|48}}

| dist_ly = 4100±200

{{cite journal

|title=Kinematics in Young Star Clusters and Associations with Gaia DR2

|journal=The Astrophysical Journal

|volume=870 |issue=1 |pages=32 |year=2018

|arxiv=1807.02115 |bibcode=2019ApJ...870...32K

|last1=Kuhn |first1=Michael A.

|last2=Hillenbrand |first2=Lynne A.

|last3=Sills |first3=Alison

|last4=Feigelson |first4=Eric D.

|last5=Getman |first5=Konstantin V.

|s2cid=119328315

|doi=10.3847/1538-4357/aaef8c |doi-access=free

}}

| dist_pc = 1,260±70

| appmag_v = +6.3

| size_v = 28 arcmins

| constellation = Sagittarius

| radius_ly = 21

| absmag_v =

| notes =a

| names = M20, NGC 6514, Sharpless 30, RCW 147, Gum 76

}}

The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum–Centaurus Arm.

{{cite journal

|display-authors=1 |last1=Cambrésy |first1=L.

|last2=Rho |first2=J.

|last3=Marshall |first3=D. J.

|date=2011

|title=Variation of the extinction law in the Trifid nebula

|journal=Astronomy & Astrophysics

|volume=527 |pages=A141

|bibcode=2011A&A...527A.141C

|arxiv=1101.1089 |s2cid=39501333

|doi=10.1051/0004-6361/201015863}} It was discovered by Charles Messier on June 5, 1764.[http://www.messier.seds.org/m/m020.html Messier 20] Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula (the relatively dense, reddish-pink portion), a reflection nebula (the mainly NNE blue portion), and a dark nebula (the apparent 'gaps' in the former that cause the trifurcated appearance, also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers.{{cite web

|title=Trifid Nebula: A Massive Star Factory

|date=August 26, 2009

|work=Science Daily

|url=https://www.sciencedaily.com/releases/2009/08/090826073442.htm

|access-date=2010-07-06

}}

The most massive star that has formed in this region is HD 164492A, an O7.5III star with a mass more than 20 times the mass of the Sun.

{{cite journal

|display-authors=1 |last1=Rho |first1=J.

|last2=Ramírez |first2=S. V.

|last3=Corcoran |first3=M. F.

|date=2004

|title=Chandra Observation of the Trifid Nebula: X-Ray Emission from the O Star Complex and Actively Forming Pre-Main-Sequence Stars

|journal=Astrophysical Journal

|volume=607 |issue=2 |pages=904–912

|bibcode=2004ApJ...607..904R

|arxiv=astro-ph/0401377 |s2cid=119090269

|doi=10.1086/383081}}

This star is surrounded by a cluster of approximately 3100 young stars.

{{cite journal

|display-authors=1 |last1=Kuhn |first1=M. A.

|last2=Getman |first2=K. V.

|last3=Feigelson |first3=E. D.

|date=2015

|title=The Spatial Structure of Young Stellar Clusters. II. Total Young Stellar Populations

|journal=Astrophysical Journal

|volume=802 |issue=1 |pages=60

|bibcode=2015ApJ...802...60K

|arxiv=1501.05300 |s2cid=119309858

|doi=10.1088/0004-637X/802/1/60}}