X-shooter study of accretion in Chamaeleon I

Manara, C. F.; Testi, L.; Herczeg, Gregory J.; Pascucci, Ilaria; Alcalá, J. M.; Natta, A.; Antoniucci, S.; Fedele, D.; Mulders, Gijs D.; Henning, Thomas; Mohanty, Subhanjoy; Prusti, T.; Rigliaco, E.

doi:10.1051/0004-6361/201630147

Cited by 173 publications

(270 citation statements)

References 122 publications

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“…Differences in results between the B-band and U-band accretion rates are likely attributable to the large scatter in the Bband at average and weaker accretion rates. This distribution of accretion rates is consistent with the distribution of accretion rates measured for stars of similar mass (e.g., Fang et al 2013;Venuti et al 2014;Manara et al 2017). However, the distribution demonstrates the importance of accretion bursts in models of disk evolution.…”

Section: Accretion On Different Timescalessupporting

confidence: 85%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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The variability of young stellar objects is mostly driven by star-disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths of DṼ 2.5 mag that last for days to months and often appear to occur stochastically. In 2014-2015, extinctions that repeated with a quasi-period of 21 days over several months are the first empirical evidence of slow warps predicted by magnetohydrodynamic simulations to form at a few stellar radii away from the central star. The reddening is consistent with =  R 3.85 0.5 V and, along with an absence of diffuse interstellar bands, indicates that some dust processing has occurred in the disk. The 2015-2016 multiband light curve includes variations in spot coverage, extinction, and accretion, each of which results in different traces in color-magnitude diagrams. This light curve is initially dominated by a month-long extinction event and a return to the unocculted brightness. The subsequent light curve then features spot modulation with a 7.03 day period, punctuated by brief, randomly spaced extinction events. The accretion rate measured from U-band photometry ranges from´-1.3 10 8 to´-1.1 10 10 M e yr −1 (excluding the highest and lowest 5% of high-and low-accretion rate outliers), with an average of4.7 -10 9 M e yr −1 . A total of 50% of the mass is accreted during bursts of >´-12.8 10 9 M e yr -1, which indicates limitations on analyses of disk evolution using single-epoch accretion rates.

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Section: Accretion On Different Timescalessupporting

confidence: 85%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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“…On the contrary, the age estimate using the new distance suggests that the Chamaeleon I stellar population is 1 Myr younger than previously found. Manara et al (2016Manara et al ( , 2017. The red diamonds and blue circles are used for L computed with the distance of 160 pc found by Whittet et al (1997) and using our distance of 179 pc, respectively.…”

Section: Discussionmentioning

confidence: 99%

A revised estimate of the distance to the clouds in the Chamaeleon complex using the Tycho–Gaia Astrometric Solution

Voirin¹,

Manara²,

Prusti³

2018

A&A

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Context. The determination of the distance to dark star-forming clouds is a key parameter to derive the properties of the cloud itself, and of its stellar content. This parameter is still loosely constrained even in nearby star-forming regions. Aims. We want to determine the distances to the clouds in the Chamaeleon-Musca complex and to explore the connection between these clouds and the large scale cloud structures in the galaxy. Methods. We use the newly estimated distances obtained from the parallaxes measured by the Gaia satellite and included in the Tycho-Gaia Astrometric Solution catalog. When known members of a region are included in this catalog we use their parallaxes to infer the distance to the cloud. Otherwise, we analyze the dependence of the color excess on the distance of the stars and look for a turn-on of this excess, which is a proxy of the position of the front-edge of the star-forming cloud. Results. We are able to measure the distance to the three Chamaeleon clouds. The distance to Chamaeleon I is 179 +11+11 −10−10 pc, where the quoted uncertainties are statistical and systematic uncertainties, respectively, ∼20 pc further away than previously assumed. The Chamaeleon II cloud is located at the distance of 181 +6+11 −5−10 pc, which agrees with previous estimates. We are able to measure for the first time a distance to the Chamaeleon III cloud of 199 +8+12 −7−11 pc. Finally, the distance of the Musca cloud is smaller than 603 +91+133pc. These estimates do not allow us to distinguish between the possibility that the Chamaeleon clouds are part of a sheet of clouds parallel to the galactic plane, or perpendicular to it. Conclusions. We have measured a larger distance to the Chamaeleon I cloud than assumed in the past, confirmed the distance to the Chamaeleon II region, and measured for the first time the distance to the Chamaleon III cloud. These values are consistent with the scenario where the three clouds are part of a single large scale structure. Gaia Data Release 2 will allow us to put more stringent constraints on the distances to these clouds by giving us access to parallax measurements for a larger number of members of these regions.

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“…All observational data used in this analysis were previously published; the ALMA data surveys of disk masses were presented by Ansdell et al (2016) and Pascucci et al (2016); the X-Shooter surveys of mass accretion rates were presented by Alcalá et al (2014Alcalá et al ( , 2017 and Manara et al (2014Manara et al ( , 2016aManara et al ( , 2017. The dust mass and mass accretion in Lupus were jointly analyzed by Manara et al (2016b).…”

Section: Homogeneous Analysis Of Stellar and Disk Propertiesmentioning

confidence: 99%

Constraints from Dust Mass and Mass Accretion Rate Measurements on Angular Momentum Transport in Protoplanetary Disks

Mulders

Pascucci

Manara

et al. 2017

ApJ

123

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In this paper, we investigate the relation between disk mass and mass accretion rate to constrain the mechanism of angular momentum transport in protoplanetary disks. We find a correlation between dust disk mass and mass accretion rate in Chamaeleon I with a slope that is close to linear, similar to the one recently identified in Lupus. We investigate the effect of stellar mass and find that the intrinsic scatter around the best-fit M dust - M andṀ acc - M relations is uncorrelated. We simulate synthetic observations of an ensemble of evolving disks using a Monte Carlo approach and find that disks with a constant α viscosity can fit the observed relations between dust mass, mass accretion rate, and stellar mass but overpredict the strength of the correlation between disk mass and mass accretion rate when using standard initial conditions. We find two possible solutions. In the first one, the observed scatter in M dust andṀ acc is not primordial, but arises from additional physical processes or uncertainties in estimating the disk gas mass. Most likely grain growth and radial drift affect the observable dust mass, while variability on large timescales affects the mass accretion rates. In the second scenario, the observed scatter is primordial, but disks have not evolved substantially at the age of Lupus and Chamaeleon I owing to a low viscosity or a large initial disk radius. More accurate estimates of the disk mass and gas disk sizes in a large sample of protoplanetary disks, through either direct observations of the gas or spatially resolved multiwavelength observations of the dust with ALMA, are needed to discriminate between both scenarios or to constrain alternative angular momentum transport mechanisms such as MHD disk winds.

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X-shooter study of accretion in Chamaeleon I

Cited by 173 publications

References 122 publications

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

A revised estimate of the distance to the clouds in the Chamaeleon complex using the Tycho–Gaia Astrometric Solution

Constraints from Dust Mass and Mass Accretion Rate Measurements on Angular Momentum Transport in Protoplanetary Disks

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