S Coronae Australis

S Coronae Australis (S CrA), is a young binary star system estimated to be around 2 million years old located in the constellation Corona Australis. It is composed of a G-type main sequence star that is about as luminous as and just over twice as massive as the Sun, and a smaller K-type main sequence star that has around 50-60% of the Sun's luminosity and 1.3 times its mass. Both stars are T Tauri stars and both show evidence of having circumstellar disks. The system is around 140 parsecs distant.^[4]

S Coronae Australis

A visual band light curve for S Coronae Australis, adapted from Mundt (1979).[1] The error bar shown on the left-most point applies to all points.
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Corona Australis
Right ascension	19h 01m 08.59709s[2]
Declination	−36° 57′ 19.8950″[2]
Apparent magnitude (V)	10.49 - 13.20[3]
Characteristics
Spectral type	G0Ve + K0Ve[4]
Variable type	T Tau[3]
Astrometry
A
Radial velocity (Rv)	0.0[5] km/s
Proper motion (μ)	RA: +7.054[6] mas/yr Dec.: −26.511[6] mas/yr
Parallax (π)	6.2291±0.0683 mas[6]
Distance	524 ± 6 ly (161 ± 2 pc)
B
Radial velocity (Rv)	+6.0[7] km/s
Proper motion (μ)	RA: +2.477[8] mas/yr Dec.: −28.079[8] mas/yr
Parallax (π)	6.7857±0.0745 mas[8]
Distance	481 ± 5 ly (147 ± 2 pc)
Details
A
Mass	0.8[9] M☉
Radius	2.3[9] R☉
Luminosity	1.7[9] L☉
Surface gravity (log g)	3.6[10] cgs
Temperature	4,300[11] K
Rotation	7.3[9] days
Rotational velocity (v sin i)	10[10] km/s
B
Mass	0.6[11] M☉
Luminosity	0.76[11] L☉
Temperature	3,800[11] K
Other designations
S CrA, S Coronae Australis, HH 82
Database references
SIMBAD	data

Johann Friedrich Julius Schmidt discovered that the star is a variable star, in 1866. It appeared with its variable star designation in Annie Jump Cannon's 1907 work Second Catalogue of Variable Stars.^[12]