An accurate distance to 2M1207Ab

Ducourant, C.; Teixeira, R.; Chauvin, G.; Daigne, G.; Campion, J.-F. Le; Song, Inseok; Zuckerman, B.

doi:10.1051/0004-6361:20078886

Cited by 65 publications

(67 citation statements)

References 39 publications

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“…Table 4. Original data for β Pictoris, TWA and Tucana/Horologium members used in our kinematical analysis from ESA 1997, Mamajek (2005), Torres et al (2006) and Ducourant et al (2008) together with the derived heliocentric spatial coordinates and velocities derived in this work. …”

Section: Discussionmentioning

confidence: 99%

“…Then, we created catalogs of measured positions (x, y), internal magnitudes, and associated errors for all stars on each frame. Observational data were processed through a global treatment, as described in Ducourant et al (2007Ducourant et al ( , 2008, and a solution was derived for TWA22 AB relative to background stars (14.5 ≤ I ≤ 18.5 mag). In our astrometry data reduction and analysis, we ignore any influence of binarity.…”

Section: Trigonometric Parallax and Proper Motionmentioning

confidence: 99%

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Kinematic analysis and membership status of TWA22 AB

Teixeira

Ducourant

Chauvin³

et al. 2009

A&A

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Context. TWA22 was initially regarded as a member of the TW Hydrae association (TWA). In addition to being one of the youngest (≈8 Myr) and nearest (≈20 pc) stars to Earth, TWA22 has proven to be very interesting after being resolved as a tight, very lowmass binary. This binary can serve as a very useful dynamical calibrator for pre-main sequence evolutionary models. However, its membership in the TWA has been recently questioned despite due to the lack of accurate kinematic measurements. Aims. Based on proper motion, radial velocity, and trigonometric parallax measurements, we aim here to re-analyze the membership of TWA22 to young, nearby associations. Methods. Using the ESO NTT/SUSI2 telescope, we observed TWA22 AB during 5 different observing runs over 1.2 years to measure its trigonometric parallax and proper motion. This is a part of a larger project measuring trigonometric parallaxes and proper motions of most known TWA members at a sub-milliarcsec level. HARPS at the ESO 3.6 m telescope was also used to measure the system's radial velocity over 2 years. Results. We report an absolute trigonometric parallax of TWA22 AB, π = 57.0 ± 0.7 mas, corresponding to a distance 17.5 ± 0.2 pc from Earth. Measured proper motions of TWA 22AB are μ α cos(δ) = −175.8 ± 0.8 mas/yr and μ δ = −21.3 ± 0.8 mas/yr. Finally, from HARPS measurements, we obtain a radial velocity V rad = 14.8 ± 2.1 km s −1 . Conclusions. A kinematic analysis of TWA22 AB space motion and position implies that a membership of TWA22 AB to known young, nearby associations can be excluded except for the β Pictoris and TW Hydrae associations. Membership probabilities based on the system's Galactic space motion and/or the trace-back technique support a higher chance of being a member to the β Pictoris association. Membership of TWA22 in the TWA cannot be fully excluded because of large uncertainties in parallax measurements and radial velocities and to the uncertain internal velocity dispersion of its members.

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Section: Discussionmentioning

confidence: 99%

Section: Trigonometric Parallax and Proper Motionmentioning

confidence: 99%

Kinematic analysis and membership status of TWA22 AB

Teixeira

Ducourant

Chauvin³

et al. 2009

A&A

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“…All measurements of a field are globally reduced through a block-adjustment-type iterative procedure described in Ducourant et al (2007Ducourant et al ( , 2008. The philosophy of this treatment is to compute simultaneously the unknown parameters of all stars (correction to standard coordinates, proper motions, parallaxes) and the unknown plate parameters of all frames.…”

Section: Trigonometric Parallax and Proper Motion Determinationmentioning

confidence: 99%

The TW Hydrae association: trigonometric parallaxes and kinematic analysis

Ducourant

Teixeira

Galli

et al. 2014

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135

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Context. The nearby TW Hydrae association (TWA) is currently a benchmark for the study of the formation and evolution of young low-mass stars, circumstellar disks, and the imaging detection of planetary companions. For these studies, it is crucial to evaluate the distance to group members in order to access their physical properties. Membership of several stars is strongly debated and age estimates vary from one author to another with doubts about coevality. Aims. We revisit the kinematic properties of the TWA in light of new trigonometric parallaxes and proper motions to derive the dynamical age of the association and physical parameters of kinematic members. Methods. Using observations performed with the New Technology Telescope (NTT) from ESO we measured trigonometric parallaxes and proper motions for 13 stars in TWA. Results. With the convergent point method we identify a co-moving group with 31 TWA stars. We deduce kinematic distances for seven members of the moving group that lack trigonometric parallaxes. A traceback strategy is applied to the stellar space motions of a selection of 16 of the co-moving objects with accurate and reliable data yielding a dynamical age for the association of t 7.5 ± 0.7 Myr. Using our new parallaxes and photometry available in the literature we derive stellar ages and masses from theoretical evolutionary models. Conclusions. With new parallax and proper motion measurements from this work and current astrometric catalogs we provide an improved and accurate database for TWA stars to be used in kinematical analysis. We conclude that the dynamical age obtained via traceback strategy is consistent with previous age estimates for the TWA, and is also compatible with the average ages derived in the present paper from evolutionary models for pre-main-sequence stars.

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“…Data have been measured and reduced using software developed in Bordeaux (see Ducourant et al 2007). We have derived preliminary proper motions for 89 stars in the zone covered by our observations with an accuracy of σ μ = 1 − 3 mas yr −1 (Figure 2).…”

Section: Astrometrymentioning

confidence: 99%

The dynamics of an extremely young cluster probed for the first time

et al. 2009

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Abstract. We present a proper-motion program that we have developed at ESO to measure, for the first time, proper motions of members of the nearby (125 pc), very young (4 × 10 5 yr) infrared ρ Ophiuchi cluster. Repeated imaging over an extended period will allow us to measure the global proper motion of the cluster and its velocity dispersion and will provide access to the ∼ 1 km s −1 velocities for objects as faint as K = 15.7 mag. Access to the velocity field of such an extremely young cluster is of crucial importance to investigate the origin and early evolution of open cluster systems.

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An accurate distance to 2M1207Ab

Cited by 65 publications

References 39 publications

Kinematic analysis and membership status of TWA22 AB

Kinematic analysis and membership status of TWA22 AB

The TW Hydrae association: trigonometric parallaxes and kinematic analysis

The dynamics of an extremely young cluster probed for the first time

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