Apsidal Motion and Physical Parameters in the Eclipsing System V490 Sct

Abstract

Abstract We report long-term UBVRIR c I c photometry of the highly eccentric 12.04 day detached eclipsing binary V490 Sct ( V = 13.1, B9.5+A0, e = 0.40), which we use to determine its relative and absolute parameters. The absolute masses, radii, and temperatures are M A = 2.33 ± 0.07 M ⊙ , R A = 1.90 ± 0.04 R ⊙ , and T A = 9960 ± 60 K for the primary and M B = 2.23±0.07 M ⊙ , R B = 1.86 ± 0.04 R ⊙ , and T B = 9700 ± 80 K for the secondary. The system displays a slow periastron advance that is dominated by General Relativity (GR). Our measurement, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>ω</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> <mml:mo>=</mml:mo> <mml:mn>0.86</mml:mn> </mml:math> deg century −1 , is 32% less then the expected rate, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>ω</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> <mml:mspace width="0.25em"/> <mml:mo>=</mml:mo> <mml:mspace width="0.25em"/> <mml:mn>1.24</mml:mn> </mml:math> deg century −1 , which has an 83% contribution from GR. A comparison with current stellar evolution models shows a good match to the measured properties at an age of about 130 Myr and Solar abundance. The photometric parallax of the system π = 0.73 ± 0.04 mas, matches the GAIA DR2 value, π = 0.76 ± 0.04 mas.

Topics & Concepts