A Census of the Chamaeleon I Star‐forming Region

Luhman, K. L.

doi:10.1086/381146

Cited by 203 publications

(431 citation statements)

References 83 publications

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“…Cha I and Cha II are the main cloud complexes in Chamaeleon where the majority of stars are being formed. The IMF is compatible with that in the field as well as IC 348 and the Orion Nebula Cluster (Comerón et al 2000;Luhman 2008). The total mass in the dark clouds of Chamaeleon is about 5000 M , Cha I containing 237 known members, and 50 members having been identified in Cha II (Luhman 2008).…”

Section: Chamaeleonsupporting

confidence: 66%

“…The IMF is compatible with that in the field as well as IC 348 and the Orion Nebula Cluster (Comerón et al 2000;Luhman 2008). The total mass in the dark clouds of Chamaeleon is about 5000 M , Cha I containing 237 known members, and 50 members having been identified in Cha II (Luhman 2008). The total stellar mass in Cha I is about 100 M , most of it being contained within a radius of 1 • (Luhman 2007), corresponding to 2.88 pc at the distance of Chamaeleon.…”

Section: Chamaeleonsupporting

confidence: 66%

“…The star-formation region Chamaeleon is 160−170 pc away from the Sun (Whittet et al 1997;Wichmann et al 1998;Bertout et al 1999) and has a median age of about 2 Myr (Luhman 2004a). Cha I and Cha II are the main cloud complexes in Chamaeleon where the majority of stars are being formed.…”

Section: Chamaeleonmentioning

confidence: 99%

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Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

253

302

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Binary populations in young star clusters show multiplicity fractions both lower and up to twice as high as those observed in the Galactic field. We follow the evolution of a population of binary stars in dense and loose star clusters starting with an invariant initial binary population and a formal multiplicity fraction of unity, and demonstrate that these models can explain the observed binary properties in Taurus, ρ Ophiuchus, Chamaeleon, Orion, IC 348, Upper Scorpius A, Praesepe, and the Pleiades. The model needs to consider solely different birth densities for these regions. The evolved theoretical orbital-parameter distributions are highly probable parent distributions for the observed ones. We constrain the birth conditions (stellar mass, M ecl , and half-mass radius, r h ) for the derived progenitors of the star clusters and the overall present-day binary fractions allowed by the present model. The results compare very well with properties of molecular cloud clumps on the verge of star formation. Combining these with previously and independently obtained constraints on the birth densities of globular clusters, we identify a weak stellar mass -half-mass radius correlation for cluster-forming cloud clumps, r h /pc ∝ (M ecl /M ) 0.13 ± 0.04 . The ability of the model to reproduce the binary properties in all the investigated young objects, covering present-day densities from 1−10 stars pc −3 (Taurus) to 2 × 10 4 stars pc −3 (Orion), suggests that environment-dependent dynamical evolution plays an important role in shaping the present-day properties of binary populations in star clusters, and that the initial binary properties may not vary dramatically between different environments.

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Section: Chamaeleonsupporting

confidence: 66%

Section: Chamaeleonsupporting

confidence: 66%

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Inverse dynamical population synthesis

Marks

Kroupa

2012

A&A

253

302

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“…In particular, the Tycho-Gaia Astrometric Solution (TGAS) from the is the commonly assumed distance to the stars in this region (e.g. Luhman 2008). …”

Section: Introductionmentioning

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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“…Take as an example recent research in Taurus (Guieu et al 2006), Orion OB1A and OB1B (Downes et al 2006), Chamaeleon I (Luhman 2004a), Chamaeleon II and Ophiuchus (Allers et al 2007) or σOrionis (Caballero et al 2007). The IPHAS survey offers a complementary approach because it allows us to use Hα as a primary selection criterion and provides a wide area coverage around or outside the well-known SFRs and clusters.…”

Section: Introductionmentioning

confidence: 99%

An IPHAS-based search for accreting very low-mass objects using VO tools

Valdivielso

Martín

Bouy

et al. 2009

A&A

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Context. The main goal of this paper is to prove that accreting very low-mass stars and brown dwarfs can be identified in IPHAS, an Hα emission survey of the northern Milky Way. Full exploitation of the IPHAS database and a future extension of it in the southern hemisphere will be useful in identifying very low-mass accreting objects near to and far from well-known star-forming regions. Aims. We have used Virtual Observatory tools to cross-match the IPHAS catalogue with the 2MASS catalogue. We defined photometric criteria to identify Hα emission sources with near-infrared colours similar to those of known young very low-mass stars and brown dwarfs. 4000 candidates were identified that met our criteria over an area of 1600 square degrees. We present low-resolution optical spectra of 113 candidates. Spectral types have been derived for the 33 candidates that have spectroscopically confirmed Hα emission, negligible reddening and spectral class M. We have also measured Hα emission and investigated the NaI doublet (818.3 nm, 819.5 nm) in these 33 objects. Methods. We confirm that 33 IPHAS candidates have strong Hα emission indicative of disc accretion for their spectral type. Twenty-three of them have spectral class M4 or later, of which ten have classes in the range M5.5-M7.0 and could thus be very young brown dwarfs. Many objects also have a weak NaI doublet, an indication of low surface gravity.Results. IPHAS provides a very valuable database for identifying accreting very low-mass stars and brown dwarfs. Virtual Observatory tools provide an efficient method for identifying these objects over large areas of the sky. Based on our success rate of 23 Hα emission objects with spectral type in the range M4-M7 out of 113 candidates with spectroscopic follow-up, we estimate that there could be hundreds of such objects in the full IPHAS survey.

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A Census of the Chamaeleon I Star‐forming Region

Cited by 203 publications

References 83 publications

Inverse dynamical population synthesis

Inverse dynamical population synthesis

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

An IPHAS-based search for accreting very low-mass objects using VO tools

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