A New Classical T Tauri Object at the Substellar Boundary in Chamaeleon II

Barrado, D.; Jayawardhana, Ray

doi:10.1086/424560

Cited by 23 publications

(20 citation statements)

References 34 publications

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“…observations and the reduction process can be obtained in Barrado y Navascués et al (2004c), Barrado y Navascués & Jayawardhana (2004) and Barrado y Navascués et al (2004b). For high-resolution spectroscopy of the two M8 targets, taken with Magellan/Baade and the echelle spectrograph MIKE, see .…”

Section: New Spectroscopic Observations: Spectral Classificationmentioning

confidence: 97%

On the age of the TW Hydrae association and 2M1207334-393254

Barrado¹

2006

A&A

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Aims. We have estimated the age of the young moving group TW Hydrae Association, a cohort of a few dozen stars and brown dwarfs located near the Sun which share the same kinematic properties and, presumably, the same origin and age. Methods. The chronology has been determined by analyzing different properties (magnitudes, colors, activity, lithium) of its members and comparing them with several well-known star forming regions and open clusters, as well as theoretical models. In addition, by using medium-resolution optical spectra of two M8 members of the association (2M1139 and 2M1207 -an accreting brown dwarf with a planetary mass companion), we have derived spectral types and measured Hα and lithium equivalent widths. We have also estimated their effective temperature and gravity, which were used to produce an independent age estimation for these two brown dwarfs. We have also collected spectra of 2M1315, a candidate member with a L5 spectral type and measured its Hα equivalent width. Results. Our age estimate for the association, 10 +10 −7 Myr, agrees with previous values cited in the literature. In the case of the two brown dwarfs, we have derived an age of 15 +15 −10 Myr, which also agree with our estimate for the whole group. Conclusions. We compared our results with recent articles published on the same subject using other techniques, and discuss the limits of the age-dating techniques.

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Section: New Spectroscopic Observations: Spectral Classificationmentioning

confidence: 97%

On the age of the TW Hydrae association and 2M1207334-393254

Barrado¹

2006

A&A

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“…Since the faintest objects are also the lowest mass ones, and given that the substellar mass limit is estimated to be around R ∼ 21 mag at the age and distance of the Chamaeleon clouds, this implies that only stellar members of the associations will have measured proper motions. In particular, the objects at the substellar boundary studied by López in Chamaeleon I and Barrado y Navascués & Jayawardhana (2004) in Chamaeleon II are not included in UCAC3.…”

Section: Object Compilationmentioning

confidence: 99%

Proper motions of young stars in Chamaeleon

Martí

Jiménez-Esteban

Bayo

et al. 2013

A&A

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Context. The study of the motion of the members of a given open cluster or stellar association provides key information about their formation and early evolution. The Chamaeleon cloud complex constitutes one of the closest and best studied low-mass star-forming regions in the Galaxy. Aims. We want to provide further evidence of the origin of the proposed stellar members of Chamaeleon and to identify interlopers from the foreground Cha and η Cha associations. Methods. We have compiled lists of spectroscopically confirmed members of Chamaeleon I and II, Cha and η Cha, and of background objects in the same line of sight. Using Virtual Observatory tools, we cross-match these lists with the UCAC3 catalogue to get the proper motions of the objects. In the vector point diagram, we identify the different moving groups, and use this information to study the membership of proposed candidate members of the associations from the literature. For those objects with available radial velocities, we compute their Galactic space velocities. We look for correlations between the known properties of the objects and their proper motions. Results. The members of the dark clouds exhibit clearly different proper motions from those of the foreground associations and of the background stars. The data suggest that Chamaeleon II could have different dynamical properties from Chamaeleon I. Although the two foreground clusters and η Chamaeleontis constitute two different proper motion groups, they have similar spatial motions, which are different from the spatial motion of Chamaeleon I. On the other hand, the space motions of the Chamaeleon II stars look more similar to those of the foreground clusters than to the Chamaeleon I stars, but the numbers are low. We find no correlations between the proper motions and the properties of the objects in either of the clouds. Conclusions. On the basis of proper motion, Chamaeleon I and II constitute two physical entities unrelated to the foreground and η Chamaeleontis clusters, but with the available data it is unclear to what extent the stellar populations in both clouds are physically connected to each other.

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“…Most of the sources were originally selected from the MIPS data because they are brighter at 70 m than 24 m. The sources 2MASS 12560549À7654106 and 2MASS 13125238À7739182 were selected from Figure 5 as previously unknown YSO candidates as described in x 4.2. C41 was chosen because it was recently noted in the literature by Barrado y Navascués & Jayawardhana (2004).…”

Section: Selected Sources In Cha IImentioning

confidence: 99%

TheSpitzerc2d Survey of Large, Nearby, Interstellar Clouds. I. Chamaeleon II Observed with MIPS

Young

Harvey

Brooke

et al. 2005

ApJ

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We present maps of over 1.5 deg 2 in Chamaeleon (Cha) II at 24, 70, and 160 m observed with the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) and a 1.2 deg 2 millimeter map from SIMBA on the Swedish-ESO Submillimetre Telescope (SEST). The c2d Spitzer Legacy Team's data reduction pipeline is described in detail. Over 1500 24 m sources and 41 70 m sources were detected by MIPS with fluxes greater than 10 . More than 40 potential YSOs are identified with a MIPS and 2MASS color-color diagram and by their spectral indices, including two previously unknown sources with 24 m excesses. Our new SIMBA millimeter map of Cha II shows that only a small fraction of the gas is in compact structures with high column densities. The extended emission seen by MIPS is compared with previous CO observations. Some selected interesting sources, including two detected at 1 mm, associated with Cha II are discussed in detail, and their SEDs are presented. The classification of these sources using MIPS data is found to be consistent with that of previous studies.

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A New Classical T Tauri Object at the Substellar Boundary in Chamaeleon II

Cited by 23 publications

References 34 publications

On the age of the TW Hydrae association and 2M1207334-393254

On the age of the TW Hydrae association and 2M1207334-393254

Proper motions of young stars in Chamaeleon

TheSpitzerc2d Survey of Large, Nearby, Interstellar Clouds. I. Chamaeleon II Observed with MIPS

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