Cold Disks: Spitzer Spectroscopy of Disks around Young Stars with Large Gaps

By Joanna Brown, G. Blake, C. Dullemond, B. Merin, Jean Augereau, A. Boogert, N. Evans, V. Geers, F. Lahuis, J. Kessler-Silacci and 2 more. 2007

154 citations recorded by the source corpus.

We have identified four circumstellar disks with a deficit of dust emission from their inner 15-50 AU. All four stars have F-G spectral type and were uncovered as part of the Spitzer Space Telescope "Cores to Disks" Legacy Program Infrared Spectrograph (IRS) first-look survey of ~100 pre-main-sequence stars. Modeling of the spectral energy distributions indicates a reduction in dust density by factors of 100-1000 from disk radii between ~0.4 and 15-50 AU but with massive gas-rich disks at larger radii. This large contrast between the inner and outer disk has led us to use the term "cold disks" to distinguish these unusual systems. However, hot dust [(0.02-0.2)Mmoon] is still present close to the central star (R ≤ 0.8 AU). We introduce the 30 μm/13 μm flux density ratio as a new diagnostic for identifying cold disks. The mechanisms for dust clearing over such large gaps are discussed. Although rare, cold disks are likely in transition from an optically thick to an optically thin state and so offer excellent laboratories for the study of planet formation.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a885612851bb79c5d83b36c1dfd56df95bc54da8

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Citations in the corpus

DISCOVERY OF SMALL-SCALE SPIRAL STRUCTURES IN THE DISK OF SAO 206462 (HD 135344B): IMPLICATIONS FOR THE PHYSICAL STATE OF THE DISK FROM SPIRAL DENSITY WAVE THEORY (2012, methodology): “The gap in the disk was predicted from the infrared (IR) spectral energy distribution (SED, Brown et al. 2007), and was subsequently imaged in sub-mm dust continuum at ∼ 0.”
The Disk Around CoKu Tauri/4: Circumbinary, Not Transitional (2008, background): “Many of these intermediate objects have optically thick “cold disks” as seen by large excesses at ∼30µm, but much smaller or nonexistent near- and mid- infrared excesses (Brown et al. 2007).”
EVIDENCE FOR DUST CLEARING THROUGH RESOLVED SUBMILLIMETER IMAGING (2008, methodology): “Out of a sample of over 100 spectra in the c2d first look program, LkHα 330 was one of only 5 disks which showed SED features characteristic of an inner hole (Brown et al. 2007).”
RESOLVED IMAGES OF LARGE CAVITIES IN PROTOPLANETARY TRANSITION DISKS (2011, methodology): “Brown et al. (2007) also used RADMC calculations to reproduce the SED alone, and later combined with these SMA data (Brown et al. 2009), but with a different density model (a power-law Σ profile, truncated at the edges).”
TRANSITIONAL DISKS AS SIGNPOSTS OF YOUNG, MULTIPLANET SYSTEMS (2011, background): “Transitional disks such as GM Aur and LkHα 330, with inner hole radii of 20 AU and 50 AU, respectively (Hughes et al. 2009, Brown et al. 2007), cannot be explained by a single orbiting planet.”
Gas density drops inside dust cavities of transitional disks around young stars observed with ALMA (2015, methodology): “They were modeled as axisymmetric dust disks with inner cavities (e.g. Strom et al. 1989; Brown et al. 2007; Espaillat etal.”
Identifying the Low-Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores (2007, background): “The nature of these objects with large infrared excesses at 24 and 70 µm compared to 3.6 − 8.0 µm could potentially be very interesting; indeed, these SEDs appear similar to those of a sample of YSOs with disks featuring large inner holes presented by Brown et al. (2007).”
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, methodology): “Article number, page 9 of 11 The F4 young star SAO 206462 (HD 135344B) is known to host a transitional disk that shows a narrow dust inner belt (Fedele et al. 2008), a large dust cavity at millimeter wavelengths (∼ 39 AU, Brown et al. 2009), and a prominent spiral arms structure (Muto et al. 2012).”
On the Diversity of the Taurus Transitional Disks: UX Tauri A and LkCa 15 (2007, background): “Extensive modeling studies of several transitional disks around T Tauri stars (D’Alessio et al. 2005; Uchida et al. 2004; Calvet et al. 2005; Espaillat et al. 2007) and F-G stars (Brown et al. 2007) have been presented.”
Spectroastrometric Imaging of Molecular Gas within Protoplanetary Disk Gaps (2008, background): “…TW Hya, SR 21 and HD 135344B, are part of the class of so-called “transitional” or “cold” disks, which show dust gaps or holes out to 4, 18 and 45AU, respectively (Calvet et al. 2002; Brown et al. 2007), at distances of 51, 120 and 84 pc (Mamajek 2005; Loinard et al. 2008; Sylvester et al. 1996).”
PROTOPLANETARY DISK STRUCTURES IN OPHIUCHUS (2009, methodology): “With a simplistic model, we place the inner edge of that cavity at Rcav ≈ 37 AU, further than the 18 AU inferred by Brown et al. (2007) from the SED alone.”
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).”
DUST FILTRATION BY PLANET-INDUCED GAP EDGES: IMPLICATIONS FOR TRANSITIONAL DISKS (2012, result): “…1992; Calvet et al. 2002, 2005; Rice et al. 2003; Schneider et al. 2003; Espaillat et al. 2007, 2008, 2010; Hughes et al. 2009), an interpretation confirmed in some cases via direct sub-mm imaging (e.g., Pietu et al. 2006; Brown et al. 2007, 2009; Hughes et al. 2009; Andrews et al. 2009, 2011).”
LARGE-SCALE ASYMMETRIES IN THE TRANSITIONAL DISKS OF SAO 206462 AND SR 21 (2014, unknown): “The dustdepleted cavity (Rcav = 36 AU, Andrews et al. 2011) in this transition disk (Brown et al. 2007, 2009) is not completely devoid of material, as rovibrational CO line observations reveal the presence of inner disk gas (Pontoppidan et al. 2008; Brown et al. 2013).”
TRANSITIONAL AND PRE-TRANSITIONAL DISKS: GAP OPENING BY MULTIPLE PLANETS? (2010, result): “…& Mahoney 1992; Calvet et al. 2002, 2005; Rice et al. 2003; Schneider et al. 2003; Espaillat et al. 2007, 2008, 2010; Hughes et al. 2009), an interpretation confirmed in some cases via direct sub-mm imaging (e.g., Pietu et al. 2006; Brown et al. 2007, 2009; Hughes et al. 2009; Andrews et al. 2009).”
Protoplanetary Disks and Their Evolution (2011, background): “The above definition has been relaxed by some researchers (Brown et al. 2007; Merin et al. 2010) to include objects with small, but still detectable, near-infrared excesses.”
THE SPITZER c2d LEGACY RESULTS: STAR-FORMATION RATES AND EFFICIENCIES; EVOLUTION AND LIFETIMES (2008, background): “The exceptions may include the “cold disks,” such as those studied by Brown et al. (2007).”
A SPATIALLY RESOLVED INNER HOLE IN THE DISK AROUND GM AURIGAE (2009, background): “Sev- eral recent millimeter studies have resolved inner emission cavities for disks with infrared SED deficits through direct imaging observations, e.g. TW Hya (Calvet et al. 2002; Hughes et al. 2007), LkHα 330 (Brown et al. 2007, 2008), and LkCa 15 (Piétu et al. 2007; Espaillat et al. 2008).”