Simultaneous spectral energy distribution and near-infrared interferometry modeling of HD 142666

TL;DR

This study models the spectral energy distribution and near-infrared interferometry of HD 142666, revealing a complex disk structure with indications of turbulence, grain growth, and additional emission components beyond simple disk models.

Contribution

It provides the first combined modeling of SED and NIR interferometry for HD 142666, incorporating new high-resolution interferometric data and exploring complex disk physics.

Findings

Disk inclined at 58 degrees with a 160-degree major axis

Disk models with vertical hydrostatic equilibrium are insufficient

Evidence of additional NIR emission components beyond simple disk models

Abstract

We present comprehensive models of Herbig Ae star, HD 142666, which aim to simultaneously explain its spectral energy distribution (SED) and near-infrared (NIR) interferometry. Our new sub-milliarcsecond resolution CHARA (CLASSIC and CLIMB) interferometric observations, supplemented with archival shorter baseline data from VLTI/PIONIER and the Keck Interferometer, are modeled using centro-symmetric geometric models and an axisymmetric radiative transfer code. CHARA's 330 m baselines enable us to place strong constraints on the viewing geometry, revealing a disk inclined at 58 degrees from face-on with a 160 degree major axis position angle. Disk models imposing vertical hydrostatic equilibrium provide poor fits to the SED. Models accounting for disk scale height inflation, possibly induced by turbulence associated with magneto-rotational instabilities, and invoking grain growth to >1 micron size in the disk rim are required to simultaneously reproduce the SED and measured visibility profile. However, visibility residuals for our best model fits to the SED indicate the presence of unexplained NIR emission, particularly along the apparent disk minor axis, while closure phase residuals indicate a more centro-symmetric emitting region. In addition, our inferred 58 degree disk inclination is inconsistent with a disk-based origin for the UX Ori-type variability exhibited by HD 142666. Additional complexity, unaccounted for in our models, is clearly present in the NIR-emitting region. We propose the disk is likely inclined toward a more edge-on orientation and/or an optically thick outflow component also contributes to the NIR circumstellar flux.