Exploring brown dwarf disks in <i>ρ </i> Ophiuchi

Natta, A.; Testi, L.; Comerón, F.; Oliva, E.; D’Antona, Francesca; Baffa, C.; Comoretto, G.; Gennari, S.

doi:10.1051/0004-6361:20021065

Cited by 127 publications

(190 citation statements)

References 36 publications

Supporting

Mentioning

171

Contrasting

Order By: Relevance

“…Previous mid-IR studies of ρ Ophiuchi have classified 31 brown dwarfs as Class II Natta et al 2002;Testi et al 2002;Barsony et al 2005;McClure et al 2010;Alves de Oliveira et al 2012). We detect 38% of the Class II brown dwarfs in our deep Herschel observations.…”

Section: Herschel/pacs Detectionssupporting

confidence: 51%

“…The existence of disks around several of these objects has been previously established from the detection of mid-IR excess (e.g. Bontemps et al 2001;Natta et al 2002;Testi et al 2002;Barsony et al 2005;McClure et al 2010;Alves de Oliveira et al 2012). The T Tauri disk population of this cluster has been studied by previous missions extending to the far-infrared regime (e.g.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Herschelsurvey of brown dwarf disks inρOphiuchi

Oliveira

Ábrahám

Márton

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Young brown dwarfs are known to possess circumstellar disks, a characteristic that is fundamental to the understanding of their formation process, and raises the possibility that these objects harbour planets. Aims. We want to characterise the far-IR emission of disks around the young brown dwarf population of the ρ Ophiuchi cluster in LDN 1688. Methods. Recent observations of the ρ Ophiuchi cluster with the Herschel Space Observatory allow us to probe the spectral energy distribution (SED) of the brown dwarf population in the far-IR, where the disk emission peaks. We performed aperture photometry at 70, 100, and 160 µm, and constructed SEDs for all previously known brown dwarfs detected. These were complemented with ancillary photometry at shorter wavelengths. We compared the observed SEDs to a grid of synthetic disks produced with the radiative transfer code MCFOST, and used the relative figure of merit estimated from the Bayesian inference of each disk parameter to analyse the structural properties. Results. We detected 12 Class II brown dwarfs with Herschel, which corresponds to one-third of all currently known brown dwarf members of ρ Ophiuchi. We did not detect any of the known Class III brown dwarfs. Comparison to models reveals that the disks are best described by an inner radius between 0.01 and 0.07 AU, and a flared disk geometry with a flaring index between 1.05 and 1.2. Furthermore, we can exclude values of the disk scale-height lower than 10 AU (measured at a fiducial radius of 100 AU). We combined the Herschel data with recent ALMA observations of the brown dwarf GY92 204 (ISO−Oph 102), and by comparing its SED to the same grid of disk models, we derived an inner disk radius of 0.035 AU, a scale height of 15 AU with a flaring index of β ∼ 1.15, an exponent for dust settling of −1.5, and a disk mass of 0.001 M . This corresponds to a disk-to-central object mass ratio of ∼1%. Conclusions. The structural parameters constrained by the extended SED coverage (inner radius and flaring index) show a narrow distribution for the young brown dwarfs detected in ρ Ophiuchi, suggesting that these objects share the same disk evolution and, perhaps, formation.

show abstract

Section: Herschel/pacs Detectionssupporting

confidence: 51%

Section: Introductionmentioning

confidence: 98%

Herschelsurvey of brown dwarf disks inρOphiuchi

Oliveira

Ábrahám

Márton

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…Most of the targets analyzed here have been previously observed in NIR spectroscopic or photometric studies (e.g., Wilking et al 1999;Luhman & Rieke 1999;Natta et al 2002Natta et al , 2004Natta et al , 2006 or with optical spectroscopy (e.g., Wilking et al 2005). The stellar parameters (SpT, A V ) derived in these works for our targets are reported in Table A.1 and in Table D.1 for N06.…”

Section: Comparison With Previous Resultsmentioning

confidence: 99%

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

Manara

Testi

Natta

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

We present new VLT/X-Shooter optical and near-infrared spectra of a sample of 17 candidate young low-mass stars and brown dwarfs located in the ρ-Ophiucus cluster. We derived the spectral type and extinction for all the targets, and then we determined their physical parameters. All the objects but one have M 0.6 M , and eight have mass below or close to the hydrogen-burning limit. Using the intensity of various permitted emission lines present in their spectra, we determined the accretion luminosity and mass accretion rates (Ṁ acc ) for all the objects. When compared with previous works targeting the same sample, we find that, in general, these objects are not as strongly accreting as previously reported, and we suggest that the reason is our more accurate estimate of the photospheric parameters. We also compare our findings with recent works in other slightly older star-forming regions, such as Lupus, to investigate possible differences in the accretion properties, but we find that the accretion properties for our targets have the same dependence on the stellar and substellar parameters as in the other regions. This leads us to conclude that we do not find evidence for a different dependence ofṀ acc with M when comparing low-mass stars and brown dwarfs. Moreover, we find a similar small ( 1 dex) scatter in theṀ acc −M relation as in some of our recent works in other star-forming regions, and no significant differences inṀ acc due to different ages or properties of the regions. The latter result suffers, however, from low statistics and sample selection biases in the current studies. The small scatter in theṀ acc −M correlation confirms that mass accretion rate measurements in the literature based on uncertain photospheric parameters and single accretion indicators, such as the Hα width, can lead to a scatter that is unphysically large. Our studies show that only broadband spectroscopic surveys coupled with a detailed analysis of the photospheric and accretion properties allows us to properly study the evolution of disk accretion rates in star-forming regions.Key words. stars: pre-main sequence -stars: formation -brown dwarfs -protoplanetary disks -accretion, accretion disksopen clusters and associations: individual: rho-Ophiucus IntroductionThe evolution of protoplanetary disks surrounding forming stars has been a major subject of study in recent years. The interest in this topic is driven by the fact that disks are the birthplace of planets. A clear understanding of the physical mechanisms driving the formation, evolution, and dispersal of disks is thus needed to constrain planet formation theories, and to explain the observed properties of our own solar system and of the wealth of exoplanetary systems discovered so far.During their evolution, the central young stellar object (YSO) and the surrounding disk interact through multiple processes, such as photoevaporation, stellar winds, and accretion of matter. The latter is a result of viscous processes happening in the disk, which drive its secular evolu...

show abstract

“…In contrast, L1688 core contains a significant number of stars with disks and protostars embedded in the densest part of the cloud (Gagné et al 2004), and the ratio stars with disks to disk-less stars is of order of one or more. The age inferred from the ratio disks/no-disk objects around ρ Ophiuchi is about 5 Myr, while for the YSOs embedded in L1688 an age t < 1 Myr is inferred (Luhman & Rieke 1999;Natta et al 2002). Other evidence of ages around 5−10 Myr near ρ Ophiuchi is given by the 2MASS color-magnitude diagrams and model isochrones at 5 Myr and 10 Myr, and by the HR diagram obtained from SEDs modeling and fitting to isochrones (Sect.…”

Section: Discussionmentioning

confidence: 96%

First stars of theρOphiuchi dark cloud

Pillitteri

Wolk

Chen

et al. 2016

A&A

View full text Add to dashboard Cite

Star formation in molecular clouds can be triggered by the dynamical action of winds from massive stars. Furthermore, X-ray and UV fluxes from massive stars can influence the life time of surrounding circumstellar disks. We present the results of a 53 ks XMMNewton observation centered on the ρ Ophiuchi A+B binary system. ρ Ophiuchi lies in the center of a ring of dust, likely formed by the action of its winds. This region is different from the dense core of the cloud (L1688 Core F) where star formation is at work. X-rays are detected from ρ Ophiuchi as well as a group of surrounding X-ray sources. We detected 89 X-ray sources, 47 of them have at least one counterpart in 2MASS+All-WISE catalogs. Based on IR and X-ray properties, we can distinguish between young stellar objects (YSOs) belonging to the cloud and background objects. Among the cloud members, we detect three debris-disk objects and 22 disk-less − Class III young stars. We show that these stars have ages in 5−10 Myr, and are significantly older than the YSOs in L1688. We speculate that they are the result of an early burst of star formation in the cloud. An X-ray energy of ≥5 × 10 44 erg has been injected into the surrounding medium over the past 5 Myr, we discuss the effects of such energy budget in relation to the cloud properties and dynamics.

show abstract

Exploring brown dwarf disks in ρ Ophiuchi

Cited by 127 publications

References 36 publications

Herschelsurvey of brown dwarf disks inρOphiuchi

Herschelsurvey of brown dwarf disks inρOphiuchi

X-Shooter study of accretion inρ-Ophiucus: very low-mass stars and brown dwarfs

First stars of theρOphiuchi dark cloud

Contact Info

Product

Resources

About