SELECTED SOUTHERN DOUBLES and VARIABLES
R.A. 15 Hours

B831 (15085-6438) in TrA is 17.0'W of B832 by and 3.0'N of the planetary nebula NGC 5844. The magnitudes are 8.7 and 10.9 respectively, separated by 2.6 arcsec towards PA 108°. Little has also changed with this pair in the last seventy years since its discovery. I see both stars as yellowish-white. Located 13′NEE (PA ~55°), and centred on the position 15h 12m 23s Dec. -64° 32′ 29″ is a lovely asterism of eight stars and finding it is easy. This object has no common name, and is not listed as a multiple star. The two brightest and closest stars (GSC9029:374 and GSC9029:167) are 7.4 and 7.8 mag. All the other stars are between 9.8 and 13.8 mag in an area of about 4.0'. It would take 20cm in dark skies to see them all, that is best viewed using medium magnifications. (c.200×)

B832 (15109-6439) in Triangulum Australe is 4.0' from the planetary nebula NGC 5844. Both stars are 9.4 and 11.4 mag, respectively, appear as yellow and orange. Since the first measure in 1927, little has changed with these stars that are separated by some 4.8 arcsec at PA 79°.

Δ194 / SLR 11 (15549-6045) is a stunningly brilliant multiple star, 1.0°NE of NGC 5979. The primary pair, SLR 11 (AB) has the components as 6.5 and 8.8 magnitudes, being separated by 1.3 arcsec at the due east PA of 93°. To me the primary is yellowish, and the secondary is blue in colour. Spectrally this star is given as B9 II, but there is some doubt, I.e. the WDS Notes, that suggests it maybe more like a K-type star. A 20cm telescope, using medium to high magnification and good seeing will just easily separate the pair. 25cm or 30cm will perhaps separate the pair more easily. Since the first measures by Sellors in 1891, the separation has slowly increased by 0.4 arcsec - with the last reliable measure made in 1962. The ‘A’ component is an unknown type suspected variable NSV 7310, displaying a small magnitude range of 6.11v to 6.15v. It is also a spectroscopic binary of uncertain period - making this a likely triple.

Two fainter yellowish companions are associated with the main pair that was discovered by Dunlop at Parramatta Observatory in 1832. The brightest lies north followed by the principle pair. Δ194 (AC) has the additional C component at 9.1 mag, some 45.0 arcsec apart at PA 48°. Since the first measures by H.C.Russell in 1883, the separation has increased by 1.5 arcsec while the PA diminished by merely 3°. The second star is Δ194 (AD) lies south preceding. At 8.7 mag, it is separated by 48.1 arcsec at PA 225.7°. Since 1883, the separation has diminished by 1.2 arcsec. Due to the small motion of these stars, little is known of the true connect of these outlying stars. The ‘C’ and ‘D’ components display opposite common proper motions. They maybe orbiting in a very long period - but it is more likely they are mere field stars.

Overall the multiple star of Δ194 makes an attractive set of stars in a prolifically starry field.

X TrA / EsB 422 / SAO253062 / (15146-7004) lays 1.4° SSW of the third magnitude star Gamma (γ) TrA, and 24' from the Triangulum Australe and Octans border. Positioned on the western corner of TrA, it can be easily found by moving an equatorial mounted telescope directly 9°W from the planetary Sa2-162. I came across the deep red star while journeying in the southern part of the constellation. Its redness is obvious when once seen. It is similar to the garnet star EsB 365 next to β Crucis. The variable star classification of X Tra was made during the turn of the century, and was classed as a Lb type irregular variable - so it tends to exhibit slow changes in brightness. In X TrA case, the brightness variations seem to be between 5.0v and 6.2v magnitude or 8.1p to 9.1p magnitude. One reference to this star is found in Webb's “Celestial Objects for Common Telescopes”'; Vol 2. under “Stars with Remarkable Spectra”. The EsB is the Epsin-Bimingham '“Red Star Catalogue”' produced photographical and visual observations in 1897, yet EsB 422 was by discovered by Fleming in 1895. It also has a large B-V magnitudes of 2.7. Spectrally it is classed as Nb, which was later upgraded to a carbon star of spectral type C5,5, corresponding to a surface temperature around 2 500K. Interestingly, Webb states 6.2 mag, however, visual estimations of red stars are notorious for being unreliable. This 6.2 mag 'minima' are still quoted in the magnitude range, though it has never been this faint since this time. (Note: Espin Updated Addition of the Handbook was made in 1917. The observation by Epsin was actually made by Innes.)