Diffraction limited infrared images of the binary star T Tauri

Ghez, A. M.; Neugebauer, G.; Gorham, P. W.; Haniff, Christopher A.; Kulkarni, S. R.; Matthews, K.; Koresko, C.; Beckwith, S.

doi:10.1086/116030

Cited by 106 publications

(148 citation statements)

References 21 publications

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“…This requires one to assume that the IR flux ratio within the T Tau S system remains constant. Evidence for large variability in at least one of the two components of the system is growing, however (Ghez et al 1991;Beck et al 2004).…”

Section: Fitting Methodsmentioning

confidence: 99%

Accurate stellar masses in the multiple system T Tauri

Duchêne¹,

Beust²,

Adjali³

et al. 2006

A&A

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Aims. We obtain accurate estimates for the individual masses of the components of the tight binary system T Tau S to settle the ongoing debate on the nature of T Tau Sa, a so-called infrared companion. Methods. We take advantage of the fact that T Tau S belongs to a triple system composed of two hierarchical orbits to simultaneously analyze the motion of T Tau Sb in the rest frames of T Tau Sa and T Tau N. With this method, it is possible to pinpoint the location of the center of mass of T Tau S and, thereby, to determine individual masses for T Tau Sa and T Tau Sb with no prior assumption about the mass/flux ratio of the system. This improvement over previous studies of the system results in much better constraints on orbital parameters. Results. We find individual masses of 2.73 ± 0.31 M for T Tau Sa and of 0.61 ± 0.17 M for T Tau Sb (in agreement with its early-M spectral type), including the uncertainty on the distance to the system. These are among the most precise estimates of the mass of any Pre-Main Sequence star, a remarkable result since this is the first system in which individual masses of T Tauri stars can be determined from astrometry only. This model-independent analysis confirms that T Tau Sa is an intermediate-mass star, presumably a very young Herbig Ae star, that may possess an almost edge-on disk.

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Section: Fitting Methodsmentioning

confidence: 99%

Accurate stellar masses in the multiple system T Tauri

Duchêne¹,

Beust²,

Adjali³

et al. 2006

A&A

Self Cite

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“…High-resolution near-infrared observations ( Dyck et al 1982) revealed early that it had a companion (hereafter T Tau S) located 0.7 00 to its south, whose nature remains somewhat mysterious. T Tau S has about twice the bolometric luminosity of the optical star T Tau (which we will refer to as T Tau N in the rest of the paper) and is very significantly more obscured (e.g., Koresko et al 1997;Stapelfeldt et al 1998); indeed, its spectral energy distribution peaks around 3 m (Ghez et al 1991). The relative motion between T Tau N and T Tau S (Ghez et al 1991;Roddier et al 2000;Duchêne et al 2002Duchêne et al , 2005) strongly suggests that they are physically bound to each other.…”

Section: Optical and Infrared Observationsmentioning

confidence: 97%

“…T Tau S has about twice the bolometric luminosity of the optical star T Tau (which we will refer to as T Tau N in the rest of the paper) and is very significantly more obscured (e.g., Koresko et al 1997;Stapelfeldt et al 1998); indeed, its spectral energy distribution peaks around 3 m (Ghez et al 1991). The relative motion between T Tau N and T Tau S (Ghez et al 1991;Roddier et al 2000;Duchêne et al 2002Duchêne et al , 2005) strongly suggests that they are physically bound to each other. In addition, the comparison between the transverse ($5 km s À1 ; Beck et al 2004) and radial ($2.5 km s À1 ; Duchêne et al 2005) components of the relative orbital motion shows that the orbit is close to being in the plane of the sky (i 30 ) and is, therefore, very likely to be roughly coplanar with the circumstellar disk surrounding T Tau N.…”

Section: Optical and Infrared Observationsmentioning

confidence: 97%

On the Nature of the Extended Radio Emission Surrounding T Tauri South

Loinard¹,

Rodrı́guez²,

D’Alessio³

et al. 2007

ApJ

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At centimeter wavelengths, the young stellar system T Tauri is known to be composed of two sources, the northern one associated with the optical star T Tau itself, and the southern one related to the infrared companion T Tau S. Here we reexamine the origin of the radio emission from these two components using archival 2 cm, 3.6 cm, and 6 cm VLA observations. The emission from the northern member is confirmed to be largely dominated by free-free radiation from an ionized wind, while the southern radio source is confirmed to consist of a compact component of magnetic origin, surrounded by an extended halo. Only moderately variable, the extended structure associated with the southern source is most likely the result of free-free radiation related to stellar winds. However, its flat spectral energy distribution, its extent, and the lack of variation of its size with the frequency of observation are incompatible with the classical picture of a fully ionized wind with constant velocity and mass-loss rate leading to an electron density distribution of n e (r) / r À2 . Instead, we propose a model in which the ionization results from the impact of a supersonic wind driven by T Tau Sb onto dense surrounding material, possibly associated with the circumbinary disk recently identified around the T Tau Sa /T Tau Sb pair. The timescales for cooling and recombination in such a situation are in good agreement with the observed morphological changes undergone by the extended structure as its driving source moves through the environment.

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“…The northern optical source (hereafter T Tau N) was found to have an infrared companion, T Tau S, approximately 0.7 to the south (Dyck et al 1982;Ghez et al 1991). T Tau S has been found also to be binary, with a separation of approximately 100 mas (Koresko 2000;Köhler et al 2000).…”

Section: Introductionmentioning

confidence: 99%

VLBI observations of T Tauri South

Smith¹,

Pestalozzi²,

Güdel³

et al. 2003

A&A

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Abstract. We report observations of the T Tauri system at 8.4 GHz with a VLBI array comprising the VLBA, VLA and Effelsberg 100 m telescopes. We detected a compact source offset approximately 40 mas from the best infrared position of the T Tau Sb component. This source was unresolved, and constrained to be less than 0.5 mas in size, corresponding to 0.07 AU or 15 R at a distance of 140 pc. The other system components (T Tau Sa, T Tau N) were not detected in the VLBI data. The separate VLA map contains extended flux not accounted for by the compact VLBI source, indicating the presence of extended emission on arcsecond scales. The compact source shows rapid variability, which together with circular polarization and its compact nature indicate that the observed flux arises from a magnetically-dominated region. Brightness temperatures in the MK range point to gyrosynchrotron as the emission mechanism for the steady component. The rapid variations are accompanied by dramatic changes in polarization, and we record an at times 100% polarized component during outbursts. This strongly suggests a coherent emission process, most probably an electron cyclotron maser. With this assumption it is possible to estimate the strength of the local magnetic field to be 1.5−3 kilogauss.

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Diffraction limited infrared images of the binary star T Tauri

Cited by 106 publications

References 21 publications

Accurate stellar masses in the multiple system T Tauri

Accurate stellar masses in the multiple system T Tauri

On the Nature of the Extended Radio Emission Surrounding T Tauri South

VLBI observations of T Tauri South

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