The frequency of binary star interlopers amongst transitional discs

Abstract

Using Non-Redundant Mask interferometry (NRM), we searched for binary companions to objects previously classified as Transitional Disks (TD). These objects are thought to be an evolutionary stage between an optically thick disk and optically thin disk. We investigate the presence of a stellar companion as a possible mechanism of material depletion in the inner region of these disks, which would rule out an ongoing planetary formation process in distances comparable to the binary separation. For our detection limits, we implement a new method of completeness correction using a combination of randomly sampled binary orbits and Bayesian inference. The selected sample of 24 TDs belong to the nearby and young star forming regions: Ophiuchus (∼ 130 pc), Taurus-Auriga (∼ 140 pc) and IC348 ( ∼ 220 pc). These regions are suitable to resolve faint stellar companions with moderate to high confidence levels at distances as low as 2 au from the central star. With a total of 31 objects, including 11 known TDs and circumbinary disks from the literature, we have found that a fraction of 0.38 ± 0.09 of the SEDs of these objects are likely due to the tidal interaction between a close binary and its disk, while the remaining SEDs are likely the result of other internal processes such as photoevaporation, grain growth, planet disk interactions. In addition, we detected four companions orbiting outside the area of the truncation radii and we propose that the IR excesses of these systems are due to a disk orbiting a secondary companion

Circumbinary, not transitional: on the spiral arms, cavity, shadows, fast radial flows, streamers, and horseshoe in the HD 142527 disc

“…Certainly stellar mass companions are ruled out in many cases (Pott et al 2010;Kohn et al 2016;Ruíz-Rodríguez et al 2016), nor would they be expected from the known statistics of the field binary population (e.g. Raghavan et al 2010).…”

Protoplanetary Disks in ρ Ophiuchus as Seen from ALMA

“…Three of these-ROph 6, 8, and 21-were identified on the basis of both, yielding 20 total infrared-identified transition disks in our sample. Of these 20 total transitional disk candidates three, ROph 2, 12, and 36, were discovered by Ruíz-Rodríguez et al (2016) to harbor tight stellar binaries (a 3  au), whose infrared signature mimicked that of transitional disks, and one, ROph 32, was discovered by Kohn et al (2016) to be a spectroscopic binary with a 0.6 aũ . ROph 6 was found to be a very tight (∼5 mas) binary by Loinard et al (2008); its mid-infrared color is due to the presence of a hot ring of material at a large distance from the star, and is most likely not indicative of a true transitional disk.…”

Silicate features in the circumstellar envelopes of the Class I binary driving source of HH 250

“…An intriguing alternative possibility is that HH 250-IRS SE may itself be a tight binary system, in which the tidal interaction with the central binary is responsible for the inner truncation of the disk common to both components. Andrews et al (2010) have studied two such cases in the TW Hya association, and Ruíz-Rodríguez et al (2016) have shown that over one third of a sample of young stellar objects in nearby star forming regions with spectral energy distributions typical of transitional disks, lacking near-infrared excesses, are actually close binaries. If this were the case of HH 250-IRS SE as well, then HH 250-IRS would be a hierarchical triple system with two nested circumbinary disks, plus one circumstellar disk around the NW component.…”