A Selection of Southern Doubles, Bright Doubles and Variable Stars

Back Forward Forward Forward

RA :  21h to 24h
Dec: -30° to -90°

Scl, PsA, Phe, Gru , Mic,
Tuc, Ind, Pav, Oct

Best Observed: Jun - Oct

(Text Ordered by RA)

SOUTHERN DOUBLES : HJ 5299 , SEE 466 , HJ 5319 , Δ238 , Δ238 : Pair 1




HJ 5299 (21548-3926) is an equal magnitude pair 0.9oSSW (6'W and 30'S) of the planetary nebula IC 5148. The magnitudes are 8.9 and 9.0, respectfully, and both appear yellow-orange as reflected in the late K0 spectral types. Later references state that the primary is a slightly hotter B8 subgiant. The pair is a wide 33.5", set at PA c. 56o. It is clearly visible in 7.5cm telescopes. Proper motions of each star makes this likely an optical pair.

SEE 466 (22050-3933) is an easily found faint pair placed 15.2'SW (0.25o) of the orangish λ Gruis. The pair is 9.3 and 10.0 mag, respectfully, and I see each star as yellow and white. Separation is 1.8"arcsec - so 15cm or 20cm is needed to see it using medium magnification. I had to inspect three faint stars in the area really to identify it. Since the first measures in 1896, the separation has not changed, but the position angle has decreased from 10o to 254o between 1896 and 1976 at a rate of 14o each decade. I examined this pair in 1994, and I estimated PA 230o, and thought the separation just a little wider. Based on the proper motions and the changes in position angle, it is likely that the pair is a true binary. The period of the system estimated to be somewhere between 160 and 300 years.

HJ 5319 (22120-3819) is a bright yellow pair is located 1.7oNE of Lambda (λ) Gruis. Herschel discovered this pair in 1836, and little has changed in the 2.1" separation since this time. From the last measure in 1985, only the position angle has been found to have decreased from 110o to 130o. On the 10th October 1879, Hargrave, using the (18cm.) 7.25" Merz Refractor at Sydney Observatory, states that he could not find the pair (and he looked, in good seeing, several times in the ensuing weeks) - an amazing discrepance considering the aperture and the brightness of the two stars. The magnitude of the stars is given as 7.6 and 7.7. It would take 15cm to be able to separate the pair cleanly. Examining the proper motions of the two stars, it is uncertain if these two stars are associated.

Δ238 (22258-7500) is a fairly brightish wide pair lies in the southernmost constellation of Octans merely some 39'S from the northern border with Indus - though the field itself is marked by mainly fainter stars below naked-eye visibility. From Australia, this pair is circumpolar. This yellow and orange pair was discovered by John Dunlop in 1828, who did not state any position angle but only its first estimated separation of 14"arcsec "f - following". John Herschel's first measure occured some four years later, and since then, the pair has increased by a roughly further 2.5"arcsec to today's 20.6"arcsec (1999), but the PA of 80o has decreased by only 3o

There is seemingly something wrong with Dunlop's observations, and at first this made me suspicious that this might not be the pair he is taking about. Dunlop's magnitudes are given as "8,12" thus being substantially different than "6.1 and 9.4" magnitude given today. His position is given as 22h 08m 56s -75o 58' (1828), which precesses to in 22h 24m 03s -74o 44' (2000). Differences between today's positions and Dunlop's given placement are about 18'NNW, but considering the effects of precession of such polar declinations, so the error is likely not so terrible. As there are no other pairs in the vicinity, it is likely Herschel's conclusion that this is Δ238 is what it is - even though the magnitudes are so disturbingly wrong. Another peculiarity appears in the Delta-m catalogue of the WDS 2002 (Nov). Dunlop's 12th magnitude of the companion is strange, but so is the WDS and the catalogues.

These appear in the Table below;

Tycho-2 Hipparcos WDS96 WDS02
8th -- -- 6.12V 6.12V 6.1v 6.19V
12th -- -- 8.72V 9.35V 9.4v 8.85V
4(v) 2.38p 2.87p 2.60V 3.23V 3.3v 2.66V

Is this an indication of a variable component?

Hipparchos Data.

"A" HIP 110712 B-V=+0.601
"B" HIP 110709 B-V=+1.095

Data in the WDS 2002 gives the following data;

Star Magnitude Star Magnitude PA (1826) Sep (1826) PA (1991) Sep (1991)
A 6.19V B 8.85V 80o 14.0" 90o 20.6"

Spectra : G3V

In the same field is a notably 7.4 magnitude red star SAO 258024 / PPM 375319 (22212-7458) whose spectral class is M3 III. Nothing is really known about this star, though it appears not to be variable. It is hard to decide if this is because the star is not variable or due to sheer lack of observations.

Δ238 : Pair 1 (22228-7503) lies some 12'W of DUN 238 and roughly in align with the red star mentioned above. This very faint pair listed as non-stars in the GSC, being listed as 13.6 and 14.1 magnitude. Presently these two star are separated by 5.7"arcsec along the NW PA of 314o. The STScI images shows both stars do exist, but the PA looks wrong.

U0075-06942218 / Mysterious Galaxy (23237-7501) is a "presumed" bright galaxy that I could not identify lies between the double and the red star. It lies 4.16' at PA 66o from the mean separation centre of Δ238 : Pair 1 (22228-7503) mention above. This USNO-A2.0 catalogue identifies the objects as the intimidatingly named U0075-06942218, and through SIMBAD's viewer aptly named "Aladin" (especially for this object gives the precise position as 22 23m 44.848s -75o 01' 18.92". It also appears in the Guide Star Catalog as GSC 2.2 S3101111114, which again gives the bright magnitudes as 11.17F and 11.53J.

It does not appear in any of the more common catalogues but with the 10.7B blue plate and 11.6R plate magnitude, you would expect that it would. Compared to the stars in Δ238 : Pair 1 (22228-7503) mentioned above, the core's brightness seems comparable, if not slightly fainter, to the star placed here. Something this bright should be easily visible in moderate telescopes. However, after looking at the STScI image, it more looks like a much fainter for nearly all amateur telescopes. What is wrong here - the magnitudes or is it just another neglected galaxy in a dim and uninteresting part of the sky?

V360 Lac / V360 Lacertae / 14 Lac (22504+4157) lies in the northern constellation of Lacerta, surrounded by the stars 13, 15 and 16 Lacertae, and lies near the border star of Omicron (ο) Andromedae. Fairly dim to the naked eye, this 5.92v magnitude star shows the variability of only 0.05 magnitudes over the period of about five days. Calculation of the orbital parameters remains difficult, though they believe the system to have an orbital tilt of about 65o above the inclination that would normally cause eclipses. Distance is presently estimated to be 600 ly.

Positions are given as ; Ie. (02583-4018). This is Right Ascension 02h 58.3m and Declination -40o 18', following the WDS Conventions.

[<< MAIN HOME Page]   [<< Last Page]    [ DS Index ]    

Last Update : 19 March 2003

Southern Astronomical Delights” © Andrew James 2002          Sydney, Australia

For any problems with this Website or Document please email me. 

Hosted by www.Geocities.ws