HD 121439, also known as HR 5240, is a solitary, bluish-white-hued star located in the southern circumpolar constellationApus. It has an apparent magnitude of 6.08, allowing it to be faintly visible to the naked eye. The object is located relatively far at a distance of 774 light-years based on Gaia DR3parallax measurements but is receding with a fairly constrained radial velocity of 4km/s. At its current distance, HD 121439's brightness is diminished by 0.57 magnitudes due to interstellar dust.
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12Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
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