Object of the Week September 1, 2024 – NGC 4125 & NGC 4121

[deepskytraveler]

NGC 4125; UGC 7118; PGC 38524; CGCG 315-019; CGCG 1205.6+6527; MCG +11-15-027
Constellation: Draco
Type: Galaxy
Morphology: E6 pec
RA: 12h 08m 06s
Dec: +65° 10’ 27”
Mag: 9.7(v)
SB: 13.3
Size: 6.1’ x 5.1’

NGC 4121; PGC 38508; CGCG 315-018; CGCG 1205.5+6523; MCG +11-15-026
Constellation: Draco
Type: Galaxy
Morphology: E
RA: 12h 07m 57s
Dec: +65° 06’ 50”
Mag: 13.5(v)
SB: 13.1
Size: 1.0’ x 0.8’

NGC 4121 and NGC 4125 are companion galaxies in the constellation Draco. NGC 4125 is the brighter and significantly larger of these two elliptical galaxies.

NGC 4125 was discovered on January 4, 1850 by English astronomer John Russell Hind. Sometime prior to 1862 NGC 4125 was independently observed by German astronomer Arthur von Auwers, however he failed to record the date of his observation. Per John Dreyer in his New General Catalogue of Nebulae and Clusters of Stars, NGC 4125 is "pretty bright, pretty large, considerably extended, much brighter middle.” NGC 4121 was discovered September 9, 1866 by German astronomer Heinrich d'Arrest. Once again per Dreyer, NGC 4121 is "faint, very small, a little extended, mottled but not resolved.”

NGC4125-ngcicproject.jpgnegative_NGC4125-ngcicproject.jpg

NGC 4125 is an elliptical galaxy, with a cataloged morphology of E6 pec (peculiar). What makes this galaxy so unusual? The January 2020 issue of Astronomy magazine says that this galaxy is “a peculiar massive elliptical galaxy in which evolved stars produced in a merger-triggered burst of star formation are pumping large amounts of gas and dust into the galaxy’s interstellar medium”. Odd ellipticals and past mergers seem to go hand-in-hand. Two things contribute to NGC 4125’s peculiar morphology. The first is the faint dust clouds which are seen in the immediate vicinity around the core. The second is the faint star stream pattern which extends beyond the bright horizontal oval region. There are at least 7 lobes spreading outward, making the galaxy look a bit like a big fuzzy star.

Here is an observation of NGC 4121 and 4125 to get you started. From The Night Sky Observer’s Guide Volume 2 Spring & Summer by George Robert Kepple and Glen W. Sanner “In 16”/18” scopes at 150x: NGC 4125 is a bright edge-on galaxy elongated 4’ x 2’ E-W containing an oval core brightening to a brilliant non-stellar nucleus. A 13th magnitude star lies 1.75’ NNE. The companion galaxy, NGC 4121, located 3.5’ SSW of NGC 4125, is a faint, diffuse, circular 45” diameter glow.”

ngc4125-dss2r-800.jpg

Now it is your turn. As always…give it a go and let us know!

[Clear Skies]

This pair is Holmberg 335. My log tells me I observed it twice, both times in a 12" SCT.

First observation in April 2011 from the Alps:

NGC4125 (Holmberg 335A) is elongated WSW to ENE, quite large and abruptly much brighter in the center. Without AV the galaxy is slightly elongated, using AV the galaxy clearly has a very elongated, brighter core. To the NNE is a mag. 14-15 star, twice that distance towards the east is mag. 10.5 star.

1/10 FoV to the south is the galaxy NGC4121 (Holmberg 335B): A small, faint, round patch, brighter in a round core.

Second time was in May 2020, from my backyard (blog):

Both galaxies are visible.

The northern galaxy NGC4125 (Holmberg 335A) is a slightly ENE-WSW (almost east-west) elongated, large, bright streak, gradually brighter in the middle with a bright nucleus that is visible without AV. Using AV the galaxy is much larger and more elongated. The central part of the galaxy is clearly very elongated in the same direction and is suddenly even brighter in a core that is elongated in the same direction. To the ESE is a mag. 10 star (TYC4160-00977-1).

The southern galaxy NGC4121 (Holmberg 335B) is a small, faint, round patch, gradually brighter in the middle, no nucleus visible.

DSF OotW 2024-35 - Holmberg 335 Dra_1.jpeg DSF OotW 2024-35 - Holmberg 335 Dra_2.jpeg DSF OotW 2024-35 - Holmberg 335 Dra_3.jpeg

Here's the guide.

[lamperti]

Back in 1994, with an 18" at 332x: " NGC 4125 - In the same field as NGC-4121 and the brighter of the two. Nice bright center fading to the elongated edges."
"NGC 4121 - In the same field as NGC-4125 and the dimmer of the two. Considerably fainter. Could be seen with direct vision. Round, even brightness with perhaps a slight brightening to the center. Two very different galaxies in the same field!"