The Nature of Transition Circumstellar Disks. Iii. Perseus, Taurus, and Auriga

Abstract

As part of an ongoing program aiming to characterize a large number of Spitzer -selected transition disks (disks with reduced levels of near-IR and/or mid-IR excess emission), we have obtained (sub)millimeter wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 31 transition objects located in the Perseus, Taurus, and Auriga molecular clouds. We use these ground-based data to estimate disk masses, multiplicity, and accretion rates in order to investigate the mechanisms potentially responsible for their inner holes. Following our previous studies in other regions, we combine disk masses, accretion rates and multiplicity data with other information, such as SED morphology and fractional disk luminosity to classify the disks as strong candidates for the following categories: grain-growth dominated disks (7 objects), giant planet-forming disks (6 objects), photoevaporating disks (7 objects), debris disks (11 objects), and cicumbinary disks (1 object, which was also classified as a photoeavaporating disk). Combining our sample of 31 transition disks with those from our previous studies results in a sample of 74 transition objects that have been selected, characterized, and classified in an homogenous way. We discuss this combined high-quality sample in the context of the current paradigm of the evolution and dissipation of protoplanetary disks and use its properties to constrain different aspects of the key processes driving their evolution. We find that the age distribution of disks that are likely to harbor recently formed giant planets favors core accretion as the main planet formation mechanism and a ∼2-3 Myr formation timescale. Subject headings: circumstellar matter -binaries: general -planetary systems: protoplanetary disks -stars: pre-main sequence -4are still quite massive (Najita et al. 2007). Even though the broadest aspects of disk evolution summarized above are relatively well established (see Williams & Cieza, 2011 for a recent review on protoplanetary disks and their evolution), we are still far from developing a comprehensive disk evolution theory, for which additional observational constraints are much needed. The so-called "transition" objects (broadly defined as disks with inner opacity holes) are particularly useful disk evolution laboratories as they are the systems where the key physical processes mentioned above have the clearest observational signatures. This is so simply because grain growth, photevaporation, and dynamical clearing all result in reduced levels of near-and/or mid-IR excess emission, which is the defining feature of transition objects.This paper is the third part of a series from an ongoing project aiming to characterize ∼100 Spitzer -selected transition disks located in nearby star-forming regions. This coordinated project has two main goals: 1) provide observational constraints on the evolution of primordial disks, their dissipation, and the primordial to debris disk transition, and 2) identify systems with stro...

The Taurus Boundary of Stellar/Substellar (TBOSS) Survey

“…Details of the previously known TBOSS transition disk and debris disk objects are listed in Table 8. (2011); (2) Cieza et al (2012); (3) this work.…”

“…The shape of the SED -specifically spectral indices between pairs of wavelengths -or spectral line features, or the absence of gas have been used to identify transition disks and later stage debris disks (Muzerolle et al 2010;Kim et al 2013). Within the TBOSS sample, 4 transition disks are known (Currie & Sicilia-Aguilar 2011;Cieza et al 2012), along with 2 debris/photoevaporative disks (Currie & Sicilia-Aguilar 2011). Details of the previously known TBOSS transition disk and debris disk objects are listed in Table 8.…”

“…It is also noteworthy that the first discovery of a pre-brown dwarf core -a self-gravitating starless core of dust and gas with a mass in the brown-dwarf regime -is located in the dense Ophiuchus L1688 cloud (André et al 2012), Additionally, J04202555+2700355 for which the evolutionary status was previously reported as inconclusive (Currie & Sicilia-Aguilar 2011), is identified as a candidate TD here. For those targets identified in the literature the TD types, compiled from Sicilia-Aguilar (2011) andCieza et al (2012), are displayed on each SED. The candidate TDs are identified by the rising spectral index from 24-70 µm (α 24−70 µm > 0).…”

Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations

“…Several young stars with transition disks are emission-line stars that exhibit signs of accretion (e.g., Najita et al 2007b;Muzerolle et al 2010;Cieza et al 2012). As a consequence, the cavities imaged in the sub-mm should have gas as the material from the optically thick outer disk flows through the cavity to be accreted by the central object (e.g., Lubow & D'Angelo 2006).…”

The Sizes and Depletions of the Dust and Gas Cavities in the Transitional Disk J160421.7-213028

“…The main observational distinction between the two is whether the system still has significant accretion onto the central star. Transitional disks with significant accretion (on the order of - M 10 9 yr −1 ) may be compatible with planets, while those with negligible accretion may indicate starvation by photoevaporation (e.g., Alexander & Armitage 2009;Cieza et al 2012;Owen & Clarke 2012;Espaillat et al 2014). The observed small-to-zero accretion rate in J1604 suggests the latter.…”