UNVEILING THE STRUCTURE OF PRE-TRANSITIONAL DISKS

By Catherine C. Espaillat, P. D’Alessio, Jesús Hernández, E. Nagel, K. Luhman, Danisha Watson, N. Calvet, J. Muzerolle, M. McClure. 2010

192 citations recorded by the source corpus.

In the past few years, several disks with inner holes that are relatively empty of small dust grains have been detected and are known as transitional disks. Recently, Spitzer has identified a new class of “pre-transitional disks” with gaps based on near-infrared photometry and mid-infrared spectra; these objects have an optically thick inner disk separated from an optically thick outer disk by an optically thin disk gap. A near-infrared spectrum provided the first confirmation of a gap in the pre-transitional disk of LkCa 15 by verifying that the near-infrared excess emission in this object was due to an optically thick inner disk. Here, we investigate the difference between the nature of the inner regions of transitional and pre-transitional disks using the same veiling-based technique to extract the near-infrared excess emission above the stellar photosphere. However, in this work we use detailed disk models to fit the excess continua as opposed to the simple blackbody fits previously used. We show that the near-infrared excess emission of the previously identified pre-transitional disks of LkCa 15 and UX Tau A in the Taurus cloud as well as the newly identified pre-transitional disk of ROX 44 in Ophiuchus can be fit with an inner disk wall located at the dust destruction radius. We also present detailed modeling of the broadband spectral energy distributions of these objects, taking into account the effect of shadowing by the inner disk on the outer disk, but considering the finite size of the star, unlike other recent treatments. The near-infrared excess continua of these three pre-transitional disks, which can be explained by optically thick inner disks, are significantly different from that of the transitional disks of GM Aur, whose near-infrared excess continuum can be reproduced by emission from sub-micron-sized optically thin dust, and DM Tau, whose near-infrared spectrum is consistent with a disk hole that is relatively free of small dust. The structure of pre-transitional disks may be a sign of young planets forming in these disks and future studies of pre-transitional disks will provide constraints to aid in theoretical modeling of planet formation.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/347e6678b5febde993f10220fe68583981978344

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Citations in the corpus

On the theory of disc photoevaporation (2011, background): “However, ‘transition’ discs with large inner holes and large accretion rates are likely to be created through a different mechanism (e.g. Espaillat et al. 2010).”
DUST FILTRATION BY PLANET-INDUCED GAP EDGES: IMPLICATIONS FOR TRANSITIONAL DISKS (2012, background): “Pre-transitional disks still have some infrared emission from warm, optically-thick dust near the star (Espaillat et al. 2007, 2008, 2010), while transitional disks only have near- and mid-infrared emission from optically-thin dust (Calvet et al. 2002, 2005; Espaillat et al. 2010).”
LARGE-SCALE ASYMMETRIES IN THE TRANSITIONAL DISKS OF SAO 206462 AND SR 21 (2014, unknown): “Such disks are classified as transitional disks, and plenty is known about their inner disk gaps/cavities (e.g. Dutrey et al. 2008; Salyk et al. 2009; Espaillat et al. 2010; Isella et al. 2012).”
Small vs. large dust grains in transitional disks: do different cavity sizes indicate a planet? - SAO 206462 (HD 135344B) in polarized light with VLT/NACO (2013, background): “This might not appear as a contradiction, since Espaillat et al. (2010) showed that, for typical pre-transitional disks, significant porti ns of the cavity wall might be out of the shadow casted by the inner wall.”
RESOLVED IMAGES OF LARGE CAVITIES IN PROTOPLANETARY TRANSITION DISKS (2011, methodology): “Espaillat et al. (2010) modeled the DoAr 44 SED and derived a slightly larger cavity size (36AU), but within the uncertainties.”
LkCa 15: A YOUNG EXOPLANET CAUGHT AT FORMATION? (2011, background): “…the likely explanation for the ring of circumstellar light previously reported in H band (Thalmann et al. 2010), which is coincident with the ∼50 AU radius of the inner disk edge suggested by SED modeling (Espaillat et al. 2007, 2010) and directly observed in submm emission (Andrews et al. 2011).”
Ring shaped dust accumulation in transition disks (2012, methodology): “With the advent of powerful infrared space telescopes such as Spitzer, a new class of objects has been identified, called the transition disks (e.g., Espaillat et al. 2010).”
Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaporation (2010, methodology): “Currently, there is no clear consensus as to what constitutes a transition disc and both accreting (e.g. Hughes et al. 2009; Espaillat et al. 2010) and non-accreting (e.g. Cieza et al. 2010; Meŕın et al. 2010) objects have been discovered.”
THE DISK POPULATION OF THE UPPER SCORPIUS ASSOCIATION (2012, background): “A pre-transitional disk and a transitional disk have gaps and holes in their dust distributions, respectively, that are large enough to noticeably affect their SEDs (∆Rgap > 5 AU, Rhole > 1 AU, Strom et al. 1989; Calvet et al. 2005; Espaillat et al. 2007, 2010).”
Observational Signatures of Planets in Protoplanetary Disks I: Gaps Opened by Single and Multiple Young Planets in Disks (2014, background): “Discovered through their unique infrared deficit from NIR to ∼ 10 µm, which signals a lack of warm dust in the inner disk (Calvet et al. 2005; Espaillat et al. 2007, 2010), these disks have been subsequently shown to harbor large gaps or cavities with sizes often up to tens of AU in spatially…”
THE MASS DEPENDENCE BETWEEN PROTOPLANETARY DISKS AND THEIR STELLAR HOSTS (2013, unknown): “…et al. (2010), 2 = Hartigan & Kenyon (2003), 3 = Hernández et al. (2004), 4 = Furlan et al. (2011), 5 = White & Ghez (2001), 6 = Itoh et al. (2005), 7 = Espaillat et al. (2010), 8 = Duchêne et al. (1999), 9 = Kraus & Hillenbrand (2009), 10 = White et al. (1999), 11 = Prato et al. (2002), 12…”
Gas density drops inside dust cavities of transitional disks around young stars observed with ALMA (2015, unknown): “…1.4 4550 1· 0−11 145 0.66 12-14 1) Dunkin et al. (1997), 2) Pontoppidan et al. (2008), 3) Grady et al. (2009), 4) Prato et al. (2003), 5) Andrews et al. (2011), 6) Espaillat et al. (2010), 7) Piétu et al. (2007), 8) Ingleby et al. (2009), 9) Wichmann et al. (1997), 10) Natta et al. (2006), 11)…”
Protoplanetary Disks and Their Evolution (2011, background): “…evidence for an optically thin (to starlight) gap separating optically thick inner and outer disk components have been called “pre-transition” disks (Espaillat et al. 2007, 2010) because they are believed to be precursors of objects with sharp, but empty inner holes (i.e., the “classical”…”
TRANSITIONAL AND PRE-TRANSITIONAL DISKS: GAP OPENING BY MULTIPLE PLANETS? (2010, methodology): “The parameters are mostly taken from Espaillat et al. (2010), where the methods used to derive these estimates are discussed.”
Survival of molecular gas in cavities of transition disks - I. CO (2013, background): “This remaining dust is required to reproduce the near-IR excess observed toward a class of transition disks (Brown et al. 2007; Espaillat et al. 2010; A11).”