A Candidate Planetary-Mass Object With a Photoevaporating Disk in Orion

Fang, Min; Kim, Jinyoung Serena; Pascucci, Ilaria; Apai, Dániel; Manara, C. F.

doi:10.3847/2041-8213/833/2/l16

Cited by 13 publications

(12 citation statements)

References 45 publications

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“…Moving down in mass, the lowest-mass isolated objects found to harbor a disk are, to the best of our knowledge, Proplyd 133-353 (≤ 13M Jup , Fang et al 2016) In this Letter we present the first millimeter detection of one of these four extremely lowmass objects, OTS44. In Section 2, we describe in more detail the target; in Section 3, we describe our observations; in Section 4, we present our disk estimate and the comparison with the literature; and in Section 5, we present our conclusions.…”

Section: Introductionmentioning

confidence: 90%

First Millimeter Detection of the Disk around a Young, Isolated, Planetary-mass Object

Bayo

Joergens

Liu

et al. 2017

ApJL

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OTS44 is one of only four free-floating planets known to have a disk. We have previously shown that it is the coolest and least massive known free-floating planet (∼12 M Jup ) with a substantial disk that is actively accreting. We have obtained Band 6 (233 GHz) ALMA continuum data of this very young disk-bearing object. The data show a clear unresolved detection of the source. We obtained disk-mass estimates via empirical correlations derived for young, higher-mass, central (substellar) objects. The range of values obtained are between 0.07 and 0.63 M Å (dust masses). We compare the properties of this unique disk with those recently reported around highermass (brown dwarfs) young objects in order to infer constraints on its mechanism of formation. While extreme assumptions on dust temperature yield disk-mass values that could slightly diverge from the general trends found for more massive brown dwarfs, a range of sensible values provide disk masses compatible with a unique scaling relation between M dust and M * through the substellar domain down to planetary masses.

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Section: Introductionmentioning

confidence: 90%

First Millimeter Detection of the Disk around a Young, Isolated, Planetary-mass Object

Bayo

Joergens

Liu

et al. 2017

ApJL

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“…Because the UV radiation is provided by massive stars, externally induced photoevaporation is expected to be important in clusters with at least a few thousand members that are expected to host massive stars (Weidner et al 2010), and the effects of photoevaporation are more dramatic within a few parsecs from such massive stars. Direct observations of evaporating disks were obtained in the Trapezium in Orion (O'dell & Wen 1994;Bally et al 2000;Fang et al 2016), Cygnus OB2 (Wright et al 2012;Guarcello et al 2014), NGC 2244 (Balog et al 2006), NGC 1977(Kim et al 2016, and Carina (Mesa- Delgado et al 2016). Indirect evidence supporting a fast erosion of protoplanetary disks in the proximity of massive stars was obtained by observing a decline of the disk fraction close to massive stars or in regions with high local UV fields in massive clusters and associations such as NGC 2244 (Balog et al 2007), NGC 6611 (Guarcello et al 2007(Guarcello et al , 2009(Guarcello et al , 2010a, and Pismis 24 (Fang et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25

Guarcello

Biazzo

Drake

et al. 2021

A&A

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Context. The dispersal of protoplanetary disks sets the timescale that is available for planets to assemble, and thus it is one of the fundamental parameters in theories of planetary formation. Disk dispersal is determined by several properties of the central star, the disk itself, and the surrounding environment. In particular, the metallicity of disks may affect their evolution, but controversial results have been published so far: disks in low-metallicity clusters appear to disperse rapidly, while some evidence supports the existence of accreting disks that are several million years old in the Magellanic Clouds. Aims. We study the dispersal timescale of disks in Dolidze 25, the young cluster in the proximity of the Sun with the lowest metallicity, to understand whether disk evolution is affected by the low metallicity of the cluster. Methods. We analyzed Chandra ACIS-I observations of the cluster and combined the resulting source catalog with existing optical and infrared catalogs of the region. We selected the disk-bearing population in a circular region with a diameter of 1° centered on Dolidze 25 from criteria based on infrared colors, and we selected the disk-less population within a smaller central region from the X-ray sources with O infrared counterparts. In both cases, criteria were applied to discard contaminating sources in the foreground or background. We derived stellar parameters from isochrones that were fit to color-magnitude diagrams. Results. We derived a disk fraction of ∼34% and a median age of the cluster of 1.2 Myr. To minimize the effect of incompleteness and spatial inhomogeneity in the list of members, we restricted this calculation to stars in a magnitude range within which our selection of cluster members is fairly complete. We also adopted different cuts in stellar masses. When we compare this estimate with existing estimates of the disk fraction of clusters younger than 10 Myr, the disk fraction of Dolidze 25 appears to be lower than what is expected based on its age alone. Conclusions. Even though our results are not conclusive given the intrinsic uncertainty on stellar ages estimated from isochrone fitting to color-magnitude diagrams, we suggest that disk evolution in Dolidze 25 may be affected by the environment. Given the poor O-star population and low stellar density of the cluster, it is more likely that the disk dispersal timescale is dictated more by the low metallicity of the cluster than by external photoevaporation or dynamical encounters.

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“…This sample included objects with spectral type from K5 to M9.5 with typically two or more objects per spectral subclass. The spectra, fully reduced and calibrated, were made available to the community and have already been used as templates for several studies (e.g., Alcalá et al 2014Alcalá et al , 2017Banzatti et al 2014;Fang et al 2016;Manara et al 2015Manara et al , 2016Manara et al , 2017Manjavacas et al 2014;Stelzer et al 2013b;Whelan et al 2014). From the same spectra we estimated the contribution of chromospheric activity to the emission lines typically used to estimate the accretion luminosity of accreting stars, showing that this has a strong dependence on the spectral type, and hence the stellar mass, of the target.…”

Section: Introductionmentioning

confidence: 99%

An extensive VLT/X-shooter library of photospheric templates of pre-main sequence stars

Manara

Frasca

Alcalá

et al. 2017

A&A

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Context. Studies of the formation and evolution of young stars and their disks rely on knowledge of the stellar parameters of the young stars. The derivation of these parameters is commonly based on comparison with photospheric template spectra. Furthermore, chromospheric emission in young active stars impacts the measurement of mass accretion rates, a key quantity for studying disk evolution. Aims. Here we derive stellar properties of low-mass (M 2 M ) pre-main sequence stars without disks, which represent ideal photospheric templates for studies of young stars. We also use these spectra to constrain the impact of chromospheric emission on the measurements of mass accretion rates. The spectra are reduced, flux-calibrated, and corrected for telluric absorption, and are made available to the community. Methods. We derive the spectral type for our targets by analyzing the photospheric molecular features present in their VLT/X-shooter spectra by means of spectral indices and comparison of the relative strength of photospheric absorption features. We also measure effective temperature, gravity, projected rotational velocity, and radial velocity from our spectra by fitting them with synthetic spectra with the ROTFIT tool. The targets have negligible extinction (A V < 0.5 mag) and spectral type from G5 to K6, and from M6.5 to M8. They thus complement the library of photospheric templates presented in our previous publication. We perform synthetic photometry on the spectra to derive the typical colors of young stars in different filters. We measure the luminosity of the emission lines present in the spectra and estimate the noise due to chromospheric emission in the measurements of accretion luminosity in accreting stars. Results. We provide a calibration of the photospheric colors of young pre-main sequence stars as a function of their spectral type in a set of standard broad-band optical and near-infrared filters. The logarithm of the noise on the accretion luminosity normalized to the stellar luminosity is roughly constant and equal to ∼−2.3 for targets with masses larger than 1 solar mass, and decreases with decreasing temperatures for lower-mass stars. For stars with masses of ∼1.5 M and ages of ∼1−5 Myr, the chromospheric noise converts to a limit of measurable mass accretion rates of ∼3 × 10 −10 M /yr. The limit on the mass accretion rate set by the chromospheric noise is of the order of the lowest measured values of mass accretion rates in Class II objects.

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A Candidate Planetary-Mass Object With a Photoevaporating Disk in Orion

Cited by 13 publications

References 45 publications

First Millimeter Detection of the Disk around a Young, Isolated, Planetary-mass Object

First Millimeter Detection of the Disk around a Young, Isolated, Planetary-mass Object

Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25

An extensive VLT/X-shooter library of photospheric templates of pre-main sequence stars

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