Uncertainties in measurements
The most recent calculation of Stephenson 2 DFK 1's bolometric luminosity, based on SED integration (using published fluxes) and assuming a distance of 5.8 kpc, yields an even higher estimate of 630,000 L☉. It has been noted that the star's SED is peculiar and cannot be fitted to standard reddening laws. This would imply that the star has higher extinction and that it is actually more luminous, casting doubt on its membership.[6] In addition, its distance has been stated to have a relative uncertainty greater than 50%, and the star's doubtful membership, uncertain distance and differing radial velocities compared to the rest of the stars in Stephenson 2 have led to some authors to consider the star as a red supergiant unrelated to Stephenson 2 or any of the red supergiant clusters at the base of the Scutum–Centaurus Arm.[5][6] As stated in a 2012 study, the stellar association is spread over a large area, with Stephenson 2 blending into its immediate surroundings
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