Kinematical and Photometric Deconstruction of the UGC 694-IC 412 System: Evidence for a Line-of-Sight Projection

Abstract

This study re-evaluates the previously assumed interaction between the galaxy pair UGC 694 and IC 412 through a combined kinematical and photometric approach. While morphological features such as tidal bridges have been visually identified in past surveys, our quantitative analysis using SDSS DR16 kinematical data reveals a significant radial velocity offset of approximately 8372 km/s. UGC 694 exhibits a heliocentric velocity of 12683 +/- 34 km/s, placing it at a distance of approximately 188 Mpc, whereas IC 412 is located in the foreground at approximately 62 Mpc with a velocity of 4311 +/- 46 km/s. This vast spatial separation of approximately 123.5 Mpc confirms that the perceived proximity is a line-of-sight projection effect rather than a physical gravitational encounter. Furthermore, we utilize differential photometry to analyze the structural asymmetry and color distribution of UGC 694. Our photometric findings suggest that the galaxy's disturbed morphology is not a result of a tidal encounter with IC 412, but likely originates from internal evolutionary processes or minor mergers with undetected companions. This work emphasizes the critical role of multi-wavelength validation in classifying interacting systems to avoid misinterpretation due to projection effects.