Investigating the Binary Source Degeneracy for Wide-orbit Planets

Abstract Wide-orbit planets are particularly sensitive to detection by the Roman Galactic Bulge Time Domain Survey (GBTDS). This study investigates the degeneracy of these events with binary sources, focusing on how observation cadence affects the resolution of these degeneracies. We analyzed the impact of various cadences from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mn>3.6</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>minutes</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> to (5 hr) −1 , which encompasses planned cadences for both the GBTDS and cadences used by ground-based surveys like KMTNet. The results show that a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mn>15</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>minutes</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> cadence is generally sufficient to resolve this degeneracy unless the source star is a giant ( ρ ≳ 0.01).