NGC 4490 (Cocoon Galaxy) (Gentle Zoom, please)

OTA: PlaneWave 20” f/4.5

Camera: PL11002M (0.81 arsec/pxl)

Observatory: iTelescope, NM (T11)

EXPOSURES:

Red: 15 x 300 sec.

Blue: 12 x 300

Green: 12 x 300

L: 12 x 180 + 5 x 300

Total exposure ~4.25 hours

Image Width: ~16 arc-minutes

Processed by Alex Woronow (2020) using PixInsight, Topaz, Skylum, SWT

NGC 4490, the principal galaxy in this image, and NGC 4484, below it, are having an intimate interlude. Both are coming away a bit frazzled. Most likely, this is the beginning of a marriage of the two into a single entity. A trace of stellar activity already spans between the two galaxies at this epoch.

But there’s a history here of marriages past. NGC 4490 appears to possess two nuclei; perhaps the second was acquired in another recent merger—or not? Radio observations (Clemens, et al., 1999) suggest that NGC 4490 is a young galaxy (~2B-yrs old) and has been producing stars at the rate of about 5 million-solar masses/yr over its lifetime. Thus, it appears from their study that NGC 4485 is not responsible for the observed star-birth activity in NGC 4490. However, NGC 4490 probably spawned the star-birth activity now seen in NGC 4485. I’ll speculate that the young age of NGC 4490 development, concomitant with its gravitational interaction, may have thus far thwarted the normal formation of a single nucleus.

This image has far too little exposure time. The data I acquired a couple of years ago, and imaging was interrupted by a medical issue. The underlying image quality leaves much to be desired. All the images have a splay of bright streaks across them and covering about half of the image. They made it impossible to calibrate and flatten the subs properly. These obtrusive defects appear to be from cleaning (somewhat) the detector. In any case, this product is for fun…certainly it has no other value! (But, ….)