Some constellations seem to have all the luck when it comes to distinctive double stars, and surprisingly the amount of celestial real estate they occupy has little to do with it. Take Aquila, for instance, which spreads it wings over a wide swath of southern sky, but really has only one double star standout, Pi (π). Or Pegasus, the flying horse, whose wings also need a lot of celestial space in which to work. It’s home for several impressive clusters of galaxies (here and here and here), and you can’t miss its conspicuously squared asterism, but you would be hard pressed to find any autograph-worthy double stars decorating its heavenly terrain. And then there’s Pisces, a long and winding right-angled constellation that only has one semi-famous double star to its credit, Alrescha.
Possibly one of the reasons Pegasus and Pisces are so deficient in distinctive double stars is because Aries stole across the Piscean border one evening and made a quick dark-of-night raid, grabbing a large handful from both constellations. It may come as a real surprise (at least it did to me), but Aries is actually richly endowed with marvelous points of multiple starlight.
Now when telescopic attention is turned towards the Arietal Ram, most people with double star memories think of Gamma (γ) Arietis — also known as Mesarthim, also known as the Ram’s Eyes. It’s a beauty, no question, with its two gloss-white 4.5 magnitude globes hovering just 7.5” apart in black sky. But Gamma (γ) Arietis actually has a lot of competition. And you don’t have to wander far at all from its dazzling twin white lights before you begin to encounter it.
And since it’s already been mentioned several times, let’s start with the most well-known of the group, Gamma (γ).
Gamma (γ) Arietis (Mesarthim) (Σ 180) (H III 9) (5 Arietis)
HIP: 8832 SAO: 92681
RA: 01h 53.5m Dec: +19° 18’
Identifier Magnitudes Separation Position Angle WDS
STF 180 AB: 4.52, 4.58 7.50” 2° 2012
STF 180 AC: 4.52, 8.63 216.80” 81° 2012
STF 180 BC: 4.58, 8.63 215.70” 83° 2012
Bu 512 CD: 8.63, 13.60 1.60” 24° 1975
Distance: 204 Light Years
Spectral Classifications: “A” is A1, “B” is B9
This one is unquestionably a delightful 60mm target, and in fact the sketch below is a 60mm refractor view:
Greg covered Gamma (γ) Arietis well in a previous post, so I won’t spend a lot of time on it. But I have to point out he coined the best description of this pair of stars I’ve yet come across, “headlights on the mountain roads of autumn.”
Sir William Herschel gets credit for being the first person to provide statistical data on Gamma (γ), which took place on September 27th, 1779, but apparently he wasn’t the first person to corner it in a telescope. R.G. Aitken credits Robert Hooke with coming across it in 1664, and according to the WDS notes file, Hooke commented, “I took notice that it consisted of two small stars very near together; a like instance to which I have not else met in all the heavens.” As appropriate as that comment is to describing Gamma (γ) Arietis, I should add that I’ve searched Volume one of The Philosophical Transactions in which that statement is supposed to have appeared, and have had no luck whatever in turning it up. It may be buried in there somewhere, but it’s certain it doesn’t appear on page 150, as referenced in the WDS note file. If a reader happens to locate that quote, I’ll be glad to provide a link to it.
Meanwhile, we’ll wander over to Σ 221, which can be a real pain to pin down, so I’ll add another chart for it here:
The path to Σ 221 isn’t all that difficult, provided you have the correct location – which I didn’t on the first attempt. There are actually several ways to get there. The easiest, if you’re using an 8×50 finder with the customary five degree field of view, is to center the finder midway between 2.65 magnitude Beta (β) Arietis and 5.23 magnitude Eta (η) Arietis, which are four degrees apart. In the central part of the field you’ll see 5.85 magnitude HIP 9307 and 7.55 magnitude HIP 9815 pointing right at our goal, 8.05 magnitude Σ 221. You can also pick it out of the sky slightly south of the halfway point between 5.23 magnitude Eta (η) and 5.72 magnitude 15 Arietis — it lies about twenty-five arcminutes west of the line extending between those two stars.
Σ 221 (H III 68) HIP: 10088 SAO: 75175
RA: 02h 09.7m Dec: +20° 21’
Magnitudes AB: 8.13, 9.45 AC: 8.13, 12.40
Separations AB: 8.40” AC: 66.70”
Position Angles: AB: 146° (WDS 2007) AC: 227° (WDS 2000)
Distance: 1450 Light Years
Spectral Classifications: “A” and “B” are both A3
This is the dimmest of the entire group of eight stars on this tour, but it makes up for its lack of light with its subtle colors:
This pair was also visited by Sir William Herschel (on September 10th, 1782), who provided very accurate directions which still work quite well over 230 years later. His 55° 42’ south following translates in our current usage to a position angle of 145° 42’, which is very close to the 2007 WDS measure of 146°.
Burnham identifies the “C” component, which was first measured in 1856, as Wn 1 (Winnecke) on p. 22 of volume one of his 1906 catalog, an identifier no longer assigned in the WDS and one that doesn’t match the current Winnecke Double Star Catalog. The AC pair seem to be widening slowly, with Winnecke measuring the separation at 61.0” in 1856, Burnham measuring it at 63.40” in 1904, and the last measure in the WDS being at 66.70.” (Burnham 1906 Catalog, Volume 1, p. 22, and Volume 2, p. 323).
Now let’s go back to Beta (β) on our second chart (click here to open it in a second window) and we’ll head north to 1 Arietis, aka Σ 174. You’ll find its 2.90 magnitude glow slightly less than two degrees northwest of Beta (β), where it forms a triangle with Beta (β) and 5.92 magnitude 7 Arietis.
1 Arietis (Σ 174) (H I 73) HIP: 8544 SAO: 74966
RA: 01h 50.1m Dec: +22° 17’
Magnitudes: 6.33, 7.21
Position Angle: 165° (WDS 2012)
Distance: 574 Light Years
Spectral Classification: “A” is G3
This close pair eluded me completely on my first attempt due to poor seeing, but I had enough of a glimpse of its potential to work up an appetite for a return visit. Although it took several nights before the sky cooperated, it was well worth the wait:
I was so intrigued by this pair that I returned several nights later with my 80mm f/15 Mizar refractor and coaxed them into an absolutely beautiful split with a 15mm TV Plössl, which surprised me until I later discovered Greg had pried it apart in a 60mm Tasco at 96x and 128x. That’s not something I would have thought to try because of the one magnitude of difference and close separation, so give Greg credit for pushing the limits on this pair . . . . . and he says he doesn’t have Burnham-like double star vision!
And again, Sir William paid this pair a visit (November 22nd, 1782), which he described as “a considerable star.”
Now on to the last stop on this tour, Lambda (λ) Arietis. It’s 4.80 magnitudes of compound light is easily found just a bit over two degrees northeast of 1 Ari, or two degrees west of second magnitude Alpha (α). (Here’s the chart once more).
Lambda (λ) Arietis (H V 12) (SHJ 23) (STTA 21) (9 Arietis)
HIP: 9153 SAO: 75051
RA: 01h 57.9m Dec: +23° 36’
Magnitudes AB: 4.80,6.65 AC: 4.80, 9.70 AD:4.80, 9.88
Separations AB: 37.10” AC: 188.70” AD: 270.10”
Position Angles AB: 48° (WDS 2012) AC: 76° (WDS 2005) AD: 85° (WDS 2012)
Distance: 133 Light Years
Spectral Classifications: “A” is F0, “B” is F7, “C” is K
This pair is a virtual carbon copy, at least color-wise, of the second pair of this tour, Σ 221 . . . . . . . or maybe it’s the other way around – hard to know which pair emerged from its cocoon of hydrogen gas and galaxial dust first. At any rate, the primary’s soft yellow and the secondary’s hint of blue provide just the right touch of class for the intriguing patterns of scattered starlight surrounding it. The “C” and “D” components balance the view by hanging out distinctively on the east side of the primary/secondary pair. And you can certainly add this foursome to the list of stars that does well in a 60mm refractor.
And who else but Sir William again . . . . . . .
I don’t know what to say about the colors he recorded, especially the garnet for the secondary, but his separation and position angle measurements match well with the 2012 WDS numbers (his 42° north following is 48° in the current usage).
The WDS has dropped the Herschel/South identifier from Lambda, but I came across it in the second volume of Burnham’s 1906 catalog (page 317), where he identifies it with the contemporary prefix, Sh 23. Herschel and South credit Struve with a measure of Lambda (λ), but it isn’t listed in Struve’s 1827 Catalogus Novus Stellarum Duplicium et Multiplicium. Burnham and Lewis make no mention of it in their catalogs, nor is it mentioned in the Astronomische Nachricthen for the 1822 to 1824 period.
At any rate, that’s it for the first part of this tour. Stay tuned for part two . . . . . . . . and
Clear Skies! 😎