A tidally tilted sectoral dipole pulsation mode in the eclipsing binary TIC 63328020. Issue 1 (9th February 2021)

• Record Type: Journal Article
• Authors: Rappaport, S A; Kurtz, D W; Handler, G; Jones, D; Nelson, L A; Saio, H; Fuller, J; Holdsworth, D L; Vanderburg, A; Žák, J; Skarka, M; Aiken, J; Maxted, P F L; Stevens, D J; Feliz, D L; Kahraman Aliçavuş, F
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 503:Issue 1(2021)
• Page Start: 254
• Page End: 269
• Publication Date: 2021-02-09
• Subjects: binaries: general -- stars: individual: TIC 63328020 -- stars: oscillations; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab336
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We report the discovery of the third tidally tilted pulsator, TIC 63328020. Observations with the TESS satellite reveal binary eclipses with an orbital period of 1.1057 d, and δ Scuti-type pulsations with a mode frequency of 21.09533 d −1 . This pulsation exhibits a septuplet of orbital sidelobes as well as a harmonic quintuplet. Using the oblique pulsator model, the primary oscillation is identified as a sectoral dipole mode with l = 1, | m | = 1. We find the pulsating star to have $M_1 \simeq 2.5 \, {\rm M}_\odot$, $R_1 \simeq 3 \, {\rm R}_\odot$, and T eff, 1 ≃ 8000 K, while the secondary has $M_2 \simeq 1.1 \, {\rm M}_\odot$, $R_2 \simeq 2 \, {\rm R}_\odot$, and T eff, 2 ≃ 5600 K. Both stars appear to be close to filling their respective Roche lobes. The properties of this binary as well as the tidally tilted pulsations differ from the previous two tidally tilted pulsators, HD74423 and CO Cam, in important ways. We also study the prior history of this system with binary evolution models and conclude that extensive mass transfer has occurred from the current secondary to the primary.