The 
	    Ṁ
	  –M
               <sub>disk</sub> Relationship for Herbig Ae/Be Stars: A Lifetime Problem for Disks with Low Masses?

Grant, Sierra L.; Stapper, Lucas M.; Hogerheijde, Michiel R.; van Dishoeck, Ewine F.; Brittain, Sean; Vioque, Miguel

doi:10.3847/1538-3881/acf128

Cited by 5 publications

(3 citation statements)

References 102 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under the assumption that turbulence regulates angular momentum transport in the disk, we can write the kinematic disk viscosity as c 1973), where α SS = α turb , and use a combination of Equations ( 5) and (6) to determine the steady-state mass accretion rate as Fairlamb et al 2015), in good agreement with the same epoch estimates based on the Brγ line luminosity (Grant et al 2023). It is known that in HD 163296, the accretion rate experienced an abrupt increase of ≈1 dex about 20 yr ago (see Mendigutía et al 2013 and Figure 8 of Ellerbroek et al 2014).…”

Section: Angular Momentum Transportmentioning

confidence: 68%

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Zagaria,

Clarke,

Booth

et al. 2023

ApJL

View full text Add to dashboard Cite

We introduce a new technique to determine the gas turbulence and surface density in bright disk rings, under the assumption that dust growth is limited by turbulent fragmentation at the ring center. We benchmark this prescription in HD 163296, showing that our measurements are consistent with available turbulence upper limits and agree with independent estimates of the gas surface density within a factor of 2. We combine our results with literature measurements of the dust surface density and grain size to determine the dust-to-gas ratio and Stokes number in the 67 and 100 au rings. Our estimates suggest that particle clumping is taking place under the effect of streaming instability (SI) in the 100 au ring. Even though in the presence of external isotropic turbulence this process might be hindered, we provide evidence that turbulence is nonisotropic in both rings and likely originates from mechanisms (such as ambipolar diffusion) that could ease particle clumping under SI. Finally, we determine the mass accretion rate under the assumption that the disk is in steady state and turbulence regulates angular momentum transport. Our results are in tension with spectroscopic measurements and suggest that other mechanisms might be responsible for accretion, in qualitative agreement with the detection of a magnetocentrifugal wind in this system. Applying our method to larger samples can be used to statistically assess if SI is a viable mechanism to form planetesimals in bright rings.

show abstract

Section: Angular Momentum Transportmentioning

confidence: 68%

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Zagaria,

Clarke,

Booth

et al. 2023

ApJL

View full text Add to dashboard Cite

show abstract

“…This indicates that the sample considered in this work, even though it is representative in mass distribution of the IMF (Section 2), might be a subsample of the total Galactic population of intermediate-and high-mass YSOs; i.e., the subsample of sources with larger accretion rates. The results of Grant et al (2023) seem to point in this direction. It is unclear whether the Iglesias et al (2023) sample is more evolved than the one compiled for this work (Section 2), or if we have been biased in the past toward mainly identifying YSOs undergoing accretion bursts (see Section 5 for further discussion).…”

Section: Kerr Et Al (2023)mentioning

confidence: 87%

“…YSOs can be more dependent on the presence of giant planets than on time (see Pinilla et al 2022;Rich et al 2022;Stapper et al 2022Stapper et al , 2023Guzmán-Díaz et al 2023), and although it is likely that the accretion rate decreases with time, episodic accretion seems to be the norm (Fischer et al 2023;Grant et al 2023).…”

Section: Clustering Properties Of the More-massive Ysos (M >mentioning

confidence: 99%

Clustering Properties of Intermediate and High-mass Young Stellar Objects*

Vioque,

Cavieres,

González

et al. 2023

View full text Add to dashboard Cite

We have selected 337 intermediate- and high-mass young stellar objects (YSOs; 1.5–20 M ⊙) well-characterized with spectroscopy. By means of the clustering algorithm HDBSCAN, we study their clustering and association properties in the Gaia DR3 catalog as a function of stellar mass. We find that the lower-mass YSOs (1.5–4 M ⊙) have clustering rates of 55%–60% in Gaia astrometric space, a percentage similar to that found in the T Tauri regime. However, intermediate-mass YSOs in the range 4–10 M ⊙ show a decreasing clustering rate with stellar mass, down to 27%. We find tentative evidence suggesting that massive YSOs (>10 M ⊙) often (yet not always) appear clustered. We put forward the idea that most massive YSOs form via a mechanism that demands many low-mass stars around them. However, intermediate-mass YSOs form in a classical core-collapse T Tauri way, yet they do not appear often in the clusters around massive YSOs. We also find that intermediate- and high-mass YSOs become less clustered with decreasing disk emission and accretion rate. This points toward an evolution with time. For those sources that appear clustered, no major correlation is found between their stellar properties and the cluster sizes, number of cluster members, cluster densities, or distance to cluster centers. In doing this analysis, we report the identification of 55 new clusters. We tabulated all of the derived cluster parameters for the considered intermediate- and high-mass YSOs.

show abstract

Constraining the gas mass of Herbig disks using CO isotopologues

Stapper,

Hogerheijde,

van Dishoeck

et al. 2024

A&A

Self Cite

View full text Add to dashboard Cite

The total disk mass sets the formation potential for exoplanets. Obtaining the disk mass is however not an easy feat, as one needs to consider the optical thickness, temperature, photodissociation, and freeze-out of potential mass tracers. Carbon-monoxide (CO) has been used as a gas mass tracer in T Tauri disks, but was found to be less abundant than expected due to the freeze-out and chemical conversion of CO on the surfaces of cold dust grains. The disks around more massive intermediate mass pre-main sequence stars called Herbig disks are likely to be warmer, allowing for the possibility of using CO as a more effective total gas mass tracer. This work aims to obtain the gas mass and size of Herbig disks observed with ALMA and compare these to previous works on T Tauri disks and debris disks. Using ALMA archival data and new NOEMA data of ^12CO ^13CO and C^18O transitions of 35 Herbig disks within 450 pc, the masses were determined using the thermo-chemical code Dust And LInes (DALI). A grid of models was run spanning five orders of magnitude in disk mass, for which the model CO line luminosities could be linked to the observed luminosities. Survival analysis was used to obtain cumulative distributions of the resulting disk masses. These were compared with dust masses from previous work to obtain gas-to-dust ratios for each disk. In addition, radii for all three isotopologues were obtained. The majority of Herbig disks for which ^13CO and C^18O were detected are optically thick in both. For these disks, the line flux essentially only traces the disk size and only lower limits to the mass can be obtained. Computing the gas mass using a simple optically thin relation between line flux and column density results in an underestimate of the gas mass of at least an order of magnitude compared to the masses obtained with DALI. The inferred gas masses with DALI are consistent with a gas-to-dust ratio of at least 100. These gas-to-dust ratios are two orders of magnitude higher compared to those found for T Tauri disks using similar techniques, even over multiple orders of magnitude in dust mass, illustrating the importance of the chemical conversion of CO in colder T Tauri disks. Similar high gas-to-dust ratios are found for Herbig group I and II disks. Since group II disks have dust masses comparable to T Tauri disks, their higher CO gas masses illustrate the determining role of temperature. Compared to debris disks, Herbig disks have gas masses higher by four orders of magnitude. At least one Herbig disk, HD 163296, has a detected molecular disk wind, but our investigation has not turned up other detections of the CO disk wind in spite of similar sensitivities. Herbig disks are consistent with a gas-to-dust ratio of at least 100 over multiple orders of magnitude in dust mass. This indicates a fundamental difference between CO emission from Herbig disks and T Tauri disks, which is likely linked to the warmer temperature of the Herbig disks.

show abstract

The Ṁ –M _disk Relationship for Herbig Ae/Be Stars: A Lifetime Problem for Disks with Low Masses?

Cited by 5 publications

References 102 publications

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Clustering Properties of Intermediate and High-mass Young Stellar Objects*

Constraining the gas mass of Herbig disks using CO isotopologues

Contact Info

Product

Resources

About

The Ṁ –M disk Relationship for Herbig Ae/Be Stars: A Lifetime Problem for Disks with Low Masses?

Cited by 5 publications

References 102 publications

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Observing Planetesimal Formation under Streaming Instability in the Rings of HD 163296

Clustering Properties of Intermediate and High-mass Young Stellar Objects*

Constraining the gas mass of Herbig disks using CO isotopologues

Contact Info

Product

Resources

About

The Ṁ –M _disk Relationship for Herbig Ae/Be Stars: A Lifetime Problem for Disks with Low Masses?