A Likely Close-In Low-Mass Stellar Companion to the Transitional Disk Star HD 142527

TL;DR

Using high-contrast sparse aperture masking, we detected a close-in low-mass stellar companion to HD 142527, which likely influences its complex disk structure and provides new insights into star-disk interactions.

Contribution

First detection of a close-in low-mass stellar companion to HD 142527 using SAM, revealing its potential role in shaping the star's complex disk features.

Findings

Detected a stellar companion at ~12.8 AU from the primary star.

Estimated the companion's mass to be between 0.1 and 0.4 solar masses.

The companion's presence may explain the disk's inner gap and spiral features.

Abstract

With the uniquely high contrast within 0.1" (\Delta mag(L') = 5-6.5 magnitudes) available using Sparse Aperture Masking (SAM) with NACO at VLT, we detected asymmetry in the flux from the Herbig Fe star HD 142527 with a barycenter emission situated at a projected separation of 88+/-5 mas (12.8+/-1.5 AU at 145 pc) and flux ratios in H, K, and L' of 0.016+/-0.007, 0.012+/-0.008, 0.0086+/-0.0011 respectively (3-\sigma errors) relative to the primary star and disk. After extensive closure-phase modeling, we interpret this detection as a close-in, low-mass stellar companion with an estimated mass of ~0.1-0.4 M_Sun. HD 142527 has a complex disk structure, with an inner gap imaged in both the near and mid-IR as well as a spiral feature in the outer disk in the near-IR. This newly detected low-mass stellar companion may provide a critical explanation of the observed disk structure.