Speckle Interferometry of 25 Gaia Two-Parameter Potential Binaries

Paul McCudden; Russell Genet; John Major; Zachary Hartman; A. U. Kovic; Rick Wasson; Michael-James Ellis; Lou Jackson; Bradley Brungardt; Zaida Weems; Astrid Wehlitz; Evan Wille; Leon Bewersdorff; Nick Hardy; Rachel Freed; David Rowe; Thomas C. Smith; Reed Estrada; Thomas Meneghini; Reggie Jones; Tom Mason; Dwight Collins; Mark Copper

arXiv · 2604.04389

Speckle Interferometry of 25 Gaia Two-Parameter Potential Binaries

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Abstract

Gaia two-parameter (G2P) stars have cumulative errors in parallax and proper motion so great that only their mean positions were reported in DR3. One potential cause of these high errors is another star as indicated by two intensity peaks in the scans. Speckle interferometry astrometric measurements of 25 G2P stars with high multi-peak percentages were obtained with the 1.5m telescope at Mt. Wilson Observatory. Of the 25 observed G2P stars, seven had no reported Gaia companions within 5.0". We found nearby companions for all seven. The 18 other G2P stars had known Gaia companions within 2.0". Of these, 13 had separations that agreed closely with the speckle measurements but with some discrepancy in position angles, three stars did not agree in either separation or position angle and no companion was detected for the remaining two. Although some of these issues may be resolved in DR4 or DR5, others may be inherent limitations of Gaia capabilities that speckle interferometry observations may be able to fill.

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Paul McCudden, Russell Genet, John Major, Zachary Hartman, A. U. Kovic, Rick Wasson, Michael-James Ellis, Lou Jackson, Bradley Brungardt, Zaida Weems, Astrid Wehlitz, Evan Wille, Leon Bewersdorff, Nick Hardy, Rachel Freed, David Rowe, Thomas C. Smith, Reed Estrada, Thomas Meneghini, Reggie Jones, Tom Mason, Dwight Collins, Mark Copper. 2026-04-06. Speckle Interferometry of 25 Gaia Two-Parameter Potential Binaries. https://arxiv.org/abs/2604.04389

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