Coronet Cluster

{{Short description|Star in the constellation Corona Australis}}

{{Infobox open cluster|

| name = Coronet Cluster

| image = Coronet Cluster in X-Ray and Infrared.jpg

| image_size = 300px

| caption = The Coronet Cluster, R CrA is the central dominantly bright star, with reflection nebulae NGC 6726/NGC 6727 lit by TY CrA and HD 176386 to upper right and parts of IC 4812 at the lower right.

| credit =

| epoch = J2000.0

| constellation = Corona Australis

| class = II,3,m

| ra = {{RA|19|1|54}}

| dec = {{DEC|−36|57.2}}

| dist_ly = 420–550 ly

| dist_pc = 130–170 pc

| appmag_v = 8

| size_v = 26 arcmin

| mass_kg =

| mass_msol = unknown

| radius_ly = 2.1 light years

| v_hb =

| age = 0.5–2 million years

| notes = relative scarcity of circumstellar discs

| names = R CRA, G359.93-17.85 by BDB2003 catalog}}

The Coronet Cluster, also known as the R CrA cluster after its best-known member, is a small open cluster located about 170 parsecs away in the southern constellation Corona Australis, isolated at the edge of the Gould Belt.{{cite web|accessdate=2016-12-30|title=APOD - Coronet in the Southern Crown|url=http://apod.nasa.gov/apod/ap070921.html}}{{cite journal

|last1=Sicilia-Aguilar|first1=Aurora

|last2=Henning|first2=Thomas

|last3=Juha´sz|first3=Attila

|last4=Bouwman|first4=Jeroen

|last5=Garmire|first5=Gordon

|last6=Garmire|first6=Audrey

|title=Very Low Mass Objects in the Coronet Cluster: The Realm of the Transition Disks

|journal=The Astrophysical Journal|volume=687

|issue=2

|pages=1145–1167

|date=10 November 2008|doi=10.1086/591932 |url=http://iopscience.iop.org/0004-637X/687/2/1145/pdf/0004-637X_687_2_1145.pdf|arxiv = 0807.2504 |bibcode = 2008ApJ...687.1145S |s2cid=119208696

}} It is 3.5 times closer to Earth than the Orion Nebula Cluster.{{cite web|title=Coronet Cluster: A Neighbor of Star Formation (A region of star formation about 420 light years from Earth.)|url=http://sfccanth.wetpaint.com/photo/9452330/Coronet+Cluster%3A+A+Neighbor+of+Star+Formation+(A+region+of+star+formation+about+420+light+years+from+Earth.)|archive-url=https://archive.today/20130217030427/http://sfccanth.wetpaint.com/photo/9452330/Coronet+Cluster:+A+Neighbor+of+Star+Formation+(A+region+of+star+formation+about+420+light+years+from+Earth.)|url-status=dead|archive-date=17 February 2013|accessdate=10 Jan 2013}} The cluster's center is composed of mostly young stars.{{cite journal|bibcode=2012faph.confE..29S|title=The star formation and disk evolution history of a sparse region: The Coronet cluster|journal=Proceedings of the Symposium "From Atoms to Pebbles: Herschel's View of Star and Planet Formation"|pages=29|last1=Sicilia-Aguilar|first1=Aurora|last2=Henning|first2=Thomas|last3=Linz|first3=Hendrik|last4=Krause|first4=Oliver|last5=André|first5=Philippe|year=2012}} The variable T Coronae Australis is also a member, located just one arcminute from R CrA.