NGC 2442 – A Galaxy of Slightly Organized Chaos

OTA:……………….CDK17

Camera:………….SBIG STXL11002 with AOX and FW8G (0.63 arsec/pxl)

Observatory:…. Heaven’s Mirror, Chile



EXPOSURES:

…R……10 x 900 sec.

…B…...16 x 900

…G……14 x 900

…L…….14 x 900

Total exposure 19.6 hours

Image Width: 27 arc-minutes

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

This Galaxy, for some reason, received two separate designations for the top and bottom arms. One half is NGC 2442, and the other is 2443. Kind of like naming your cat’s head Skeeter and its tail Chucky. This Galaxy lies about 50M lyr from us. Andromeda Galaxy is at only 2.5 M lyr from us and has scant detail compared to this explosion of colors and structure.

There’s a physical reason for all this detail and color: it arose from a gravitational encounter with a smaller galaxy. Mihos and Bothun (1997) (MB) favors interaction with the Galaxy toward the upper left (NGC 21457) because it also may have a distorted barred-galaxy form. (The splinter-like object, on NGC 21457’s edge, appears to be an edge-on galaxy lying behind it.) Commonly, a close encounter spawns extensive star-burst activity in an interacting galaxy. The abundance of blue (reflection nebulae, given life by hot young stars) and red (HII nebula, excited by yet more star birth) regions attest to the activity that engages this Galaxy. However, to my eye, NGC 21457 does not appear to be as severely distorted as is NGC 2442, which, if it is less massive than NGC 2442, is surprising.

MB also surmise, “the asymmetric pattern of star formation in NGC 2442 is a reflection of the differing physical conditions in the gas on either side of the Galaxy. On the northern side of the Galaxy, the gas is undergoing strong shocking and dissipation along the tidally induced arm, resulting in the vigorous, localized star formation.” They also champion the idea that the interacting Galaxy passed toward the south, causing more significant distortion and greater gas flow from the Galaxy in that quadrant. They even introduced me to the terms “perigalacticon experiences” and “local gasdynamical response” to describe these interactions.

Usually, one galactic interaction leads to another, and MB suggests that these two galaxies will finally merge in about 3Gyr.

Quite apparent, a patchwork cloud permeates the scene. I presume but cannot say for sure that this is part of IFN.