Absolute Dimensions of a Flat Hierarchical Triple System KIC 6543674 from the Kepler Photometry

Abstract

Many of the Kepler close binaries are suggested to constitute hierarchical triple systems through their eclipse timing variations (ETVs). Eclipses by the third body in those systems, if observed, provide precise constraints on its physical and orbital properties, which are otherwise difficult to obtain. In this Letter, we analyze such a "tertiary event" observed only once in the KIC 6543674 system. The system consists of a short-period ($2.4\mathrm{days}$) inner eclipsing binary and a third body on a wide ($1100\mathrm{days}$) and eccentric ($e\simeq 0.6$) orbit. Analysis of three tertiary eclipses around a single inferior conjunction of the third body yields the mutual inclination between the inner and outer binary planes to be $3.3^{\circ }\pm 0.6^{\circ }$, indicating an extremely flat geometry. Furthermore, combining the timings and shapes of the tertiary eclipses with the phase curve and ETVs of the inner binary, we determine the mass and radius ratios of all three bodies in the system using the Kepler photometry alone. With the primary mass and temperature from the Kepler Input Catalog, the absolute masses, radii, and effective temperatures of the three stars are obtained as follows: $M_{\mathrm{A}}=1.2\pm 0.3M_{\odot }$, $R_{\mathrm{A}}=1.8\pm 0.1R_{\odot }$, $M_{\mathrm{B}}=1.1_{-0.2}^{+0.3}{M}_{\odot }$, $R_{\mathrm{B}}=1.4\pm 0.1R_{\odot }$, $M_{\mathrm{C}}=0.50_{-0.08}^{+0.07}{M}_{\odot }$, $R_{\mathrm{C}}=0.50\pm 0.04R_{\odot }$, $T_{\mathrm{A}}\simeq T_{\mathrm{B}}\simeq 6100\mathrm{K}$, and $T_{\mathrm{C}}<5000\mathrm{K}$. Implication for the formation scenario of close binaries is briefly discussed.

8 pages, 4 figures, accepted for publication in ApJL

References in corpus (5)

• The Dartmouth Stellar Evolution Database
• KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass Stars
• Hot Jupiters from Coplanar High-eccentricity Migration
• Very Low-Density Planets around Kepler-51 Revealed with Transit Timing Variations and an Anomaly Similar to a Planet-Planet Eclipse Event
• Eclipse Timing Variation Analyses of Eccentric Binaries with Close Tertiaries in the Kepler field

Cited by in corpus (11)

• A Comprehensive Study of the Kepler Triples via Eclipse Timing
• Photodynamical analysis of the triply eclipsing hierarchical triple system EPIC 249432662
• Six New Compact Triply Eclipsing Triples Found With TESS
• The Compact Triply Eclipsing Triple Star TIC 209409435 Discovered with TESS
• Eccentric Companions to Kepler-448b and Kepler-693b: Clues to the Formation of Warm Jupiters
• How do starspots influence the transit timing variations of exoplanets? Simulations of individual and consecutive transits
• Triply eclipsing triple stars in the northern TESS fields: TICs 193993801, 388459317 and 52041148
• Frequency Modulation of Directly Imaged Exoplanets: Geometric Effect as a Probe of Planetary Obliquity
• Multiply eclipsing candidates from the TESS satellite
• Then and now: A new look at the eclipse timing variations of hierarchical triple star candidates in the primordial $Kepler$-field, revisited by TESS
• The extraneous eclipses on binary light curves: KIC 5255552, KIC 10091110, and KIC 11495766