Object of the Week, June 14th, 2020 - Arp 103, Zwicky's Triplet, in Hercules

[Paul Alsing]

Object of the Week, June 14th, 2020 - Arp 103, Zwicky's Triplet, in Hercules

PGC 59065, MCG +08-31-003a
PGC 59061, MCG +08-31-003
PGC 59062

R.A.: 16h49m28.3s Dec.: +45°27'41" (2000)

Size: 55"x 41"

Magnitude: 14.60 (V) ; Surface brightness 22.8 Mag/arcsec²

Sorry about the late report, I’ve had a house guest for the last 4 days and got side-tracked.

When I first started doing a little due-diligence regarding this object I just put “Arp 103” into my search engine to see what I might find, looking mostly for great pictures to share. To my surprise, I found several references for (2) different locations for Arp 103. I’ve observed the “Hercules” version several times, but I had never heard of the Virgo version, which indicated that IC 3481, along with IC 3481A and IC 3483 made up the trio. While this is indeed a very nice trio, I’m not sure that it should be correctly identified as “Zwicky’s Triplet” unless there really are 2 of them. It is, in fact, Arp 175. Our pal Steve Gottlieb included this guy in his report here on June 6th, 2016, and even Steve called it Zwicky’s Triplet…

http://www.deepskyforum.com/showthre...1)-6-June-2014

Our friend Alvin Huey published the graphics that he used for an OSP talk in 2011 and shows Arp 103 as being in Virgo, but the photo he uses is the group in Hercules (page 6)… so I’m not the only one who is somewhat confused!

http://www.faintfuzzies.com/Files/OSP2011Talk.pdf

Perhaps each is “a” Zwicky Triplet rather than “the” Zwicky Triplet. All I know is that when I searched for “Zwicky’s Triplet” in Simbad, it produced Arp 103 in Hercules. .

This “other” Zwicky’s Triplet, Arp 103, is well-placed these days near midnight in my part of the world here in Southern California, being nearly overhead. Arp classified this triplet under “Elliptical and elliptical-like galaxies connected to spirals”.

ARP'S PHOTO.jpg

I have observed Arp 103 several times over the years. Photos of Arp 103 show a very tenuous arc extending upwards from the bright member of the southern pair (PGC 59061)…

Arp103_-_SDSS_DR14 LABELED.jpg

… but I have never seen even a hint of this arc. The members of Arp 103 are pretty dim and featureless, but they are not particularly difficult to see on a good night with enough aperture. All appear to be “elliptical-like”, and I have no clue as to which one is supposed to be a spiral. Perhaps someone here has had a better look at them than I have.

There is a pretty extensive article here…

https://www.cloudynights.com/topic/2...ltiple-system/

… where the author, Rick J, attempts to explain the ins and outs of the UGC 10586 system, which contains 6 members, 3 of whom are members of Arp 103!

As always, give it a go and let us know.

[Ivan Maly]

I observed the Hercules system three years ago (16", 330x, SQM 21.78) and include my record below. I think the linked paper talks also about the Virgo triplet. It is funny to note that in 1961, leading professional astronomers working the largest scopes still published sketches. In any event, their coordinates are in 1950. There is also another part of that paper series that is referenced, so if the other object is not here it is probably in that other part.

Arp 103. SDSS.

Arp 103, MCG+8-31-3. VV 710, 411 Mly. Zwicky's Triplet. UGC [10586], NGC [6241] seen [not parts of the Arp triplet]. PGC [59062] fainter than [MCG+8-31] -3. [MCG+8-31-] 3A seen. [Zwicky's triplet is the -3, -3A, and PGC - see sketch in the original Zwicky and Humason paper.]

[lamperti]

Back in 1991 I was observing NGC-6241 with a 13" at 130x. My notes stated " 'something' else fainter above (north) of it. Zwicky's triplet?" I have a note to re-observe the area with a larger aperture.

[Uwe Glahn]

Yeah, I also came across some more "Zwicky’s Triplet's" in the past. Funny thing.

And I found one entry and sketch to Arp 103. Also without tidal arm.

sketch: 27", 293x, NELM 6m5+, Seeing IV
VV710.jpg