The hybrid disks: a search and study to better understand evolution of disks

Péricaud, J.; Folco, E. Di; Dutrey, Anne; Guilloteau, S.; Piétu, V.

doi:10.1051/0004-6361/201629371

Cited by 40 publications

(44 citation statements)

References 192 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This in-dicates that HD 163296 may not exhibit as marked a depletion of CO as the other disks in our sample with CO mass estimates. While the disk HD 163296 has age estimates as low as 3 Myr (Péricaud et al 2017), we choose the common literature age value of 5 Myr for our modeling (van den Ancker et al 1998; Montesinos et al 2009). For HD 163296 we also re-derive the dust line locations with the updated Gaia DR2 distance of 100 pc.…”

Section: Hd 163296mentioning

confidence: 99%

New Constraints From Dust Lines on the Surface Densities of Protoplanetary Disks

Powell

Murray-Clay

Pérez

et al. 2019

ApJ

View full text Add to dashboard Cite

We present new determinations of disk surface density, independent of an assumed dust opacity, for a sample of 7 bright, diverse protoplanetary disks using measurements of disk dust lines. We develop a robust method for determining the location of dust lines by modeling disk interferometric visibilities at multiple wavelengths. The disks in our sample have newly derived masses that are 9-27% of their host stellar mass, substantially larger than the minimum mass solar nebula. All are stable to gravitational collapse except for one which approaches the limit of Toomre-Q stability. Our mass estimates are 2-15 times larger than estimates from integrated optically thin dust emission. We derive depleted dust-to-gas ratios with typical values of ∼10 −3 in the outer disk. Using coagulation models we derive dust surface density profiles that are consistent with millimeter dust observations. In these models, the disks formed with an initial dust mass that is a factor of ∼10 greater than is presently observed. Of the three disks in our sample with resolved CO line emission, the masses of HD 163296, AS 209, and TW Hya are roughly 3, 115, and 40 times more massive than estimates from CO respectively. This range indicates that CO depletion is not uniform across different disks and that dust is a more robust tracer of total disk mass. Our method of determining surface density using dust lines is robust even if particles form as aggregates and is useful even in the presence of dust substructure caused by pressure traps. The low Toomre-Q values observed in this sample indicate that at least some disks do not accrete efficiently.

show abstract

Section: Hd 163296mentioning

confidence: 99%

New Constraints From Dust Lines on the Surface Densities of Protoplanetary Disks

Powell

Murray-Clay

Pérez

et al. 2019

ApJ

View full text Add to dashboard Cite

show abstract

“…Later, more such objects were discovered, and the first statistical studies could be done (Lieman-Sifry et al 2016;Greaves et al 2016;Péricaud et al 2017). Our present list partly incorporates these earlier samples, and extends them to a full list of 17 dust-rich debris disks in the Solar neighborhood (Sec.…”

Section: Molecular Gas In Bright Debris Disksmentioning

confidence: 99%

Molecular Gas in Debris Disks around Young A-type Stars

Moór

Curé

Kóspál

et al. 2017

ApJ

110

176

View full text Add to dashboard Cite

According to the current paradigm of circumstellar disk evolution, gas-rich primordial disks evolve into gas-poor debris disks composed of second-generation dust. To explore the transition between these phases, we searched for 12 CO, 13 CO, and C 18 O emission in seven dust-rich debris disks around young A-type stars, using ALMA in Band 6. We discovered molecular gas in three debris disks. In all these disks, the 12 CO line was optically thick, highlighting the importance of less abundant molecules in reliable mass estimates. Supplementing our target list by literature data, we compiled a volume-limited sample of dust-rich debris disks around young A-type stars within 150 pc. We obtained a CO detection rate of 11/16 above a 12 CO J=2-1 line luminosity threshold of ∼1.4×10 4 Jy km s −1 pc 2 in the sample. This high incidence implies that the presence of CO gas in bright debris disks around young A-type stars is likely more the rule than the exception. Interestingly, dust-rich debris disks around young FG-type stars exhibit, with the same detectability threshold as for A-type stars, significantly lower gas incidence. While the transition from protoplanetary to debris phase is associated with a drop of dust content, our results exhibit a large spread in the CO mass in our debris sample, with peak values comparable to those in protoplanetary Herbig Ae disks. In the particularly CO-rich debris systems the gas may have primordial origin, characteristic of a hybrid disk.

show abstract

“…In the literature two models are proposed to explain the existence of shielded debris disks. The hybrid disk model (Kóspál et al 2013;Péricaud et al 2017) is motivated by the fact that all known representatives of this class are very young. According to this scenario, the gas in these systems is mostly primordial and dominated by hydrogen molecules that provide effective shielding for CO.…”

Section: Origin Of Gas In 49 Cet and Hd 32297mentioning

confidence: 99%

New Millimeter CO Observations of the Gas-rich Debris Disks 49 Cet and HD 32297

Moór

Kral

Ábrahám

et al. 2019

ApJ

View full text Add to dashboard Cite

Previous observations revealed the existence of CO gas at nearly protoplanetary level in several dust-rich debris disks around young A-type stars. Here we used the ALMA 7m-array to measure 13 CO and C 18 O emission toward two debris disks, 49 Cet and HD 32297, and detected similarly high CO content (>0.01 M ⊕ ). These high CO masses imply a highly efficient shielding of CO molecules against stellar and interstellar ultraviolet photons. Adapting a recent secondary gas disk model that considers both shielding by carbon atoms and self-shielding of CO, we can explain the observed CO level in both systems. Based on the derived gas densities we suggest that, in the HD 32297 disk, dust and gas are coupled and the dynamics of small grains is affected by the gaseous component. For 49 Cet, the question of coupling remains undecided. We found that the main stellar and disk properties of 49 Cet and HD 32297 are very similar to those of previously identified debris disks with high CO content. These objects constitute together the first known representatives of shielded debris disks.

show abstract

The hybrid disks: a search and study to better understand evolution of disks

Cited by 40 publications

References 192 publications

New Constraints From Dust Lines on the Surface Densities of Protoplanetary Disks

New Constraints From Dust Lines on the Surface Densities of Protoplanetary Disks

Molecular Gas in Debris Disks around Young A-type Stars

New Millimeter CO Observations of the Gas-rich Debris Disks 49 Cet and HD 32297

Contact Info

Product

Resources

About