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Observations of T Tauri Disks at Sub-AU Radii: Implications for Magnetospheric Accretion and Planet Formation
We determine inner disk sizes and temperatures for four solar-type (1-2Msolar) classical T Tauri stars, AS 207A, V2508 Oph, AS 205A,and PX Vul, using 2.2 μm observations from the Keck Interferometer.Nearly contemporaneous near-IR adaptive optics imaging photometry,optical photometry, and high-dispersion optical spectroscopy are used todistinguish contributions from the inner disks and central stars in theinterferometric observations. In addition, the spectroscopic andphotometric data provide estimates of stellar properties, mass accretionrates, and disk corotation radii. We model our interferometric andphotometric data in the context of geometrically flat accretion diskmodels with inner holes, and flared disks with puffed-up inner walls.Models incorporating puffed-up inner disk walls generally provide betterfits to the data, similar to previous results for higher mass Herbig Aestars. Our measured inner disk sizes are larger than disk truncationradii predicted by magnetospheric accretion models, with largerdiscrepancies for sources with higher mass accretion rates. We suggestthat our measured sizes correspond to dust sublimation radii, and thatoptically thin gaseous material may extend farther inward to themagnetospheric truncation radii. Finally, our inner disk measurementsconstrain the location of terrestrial planet formation as well aspotential mechanisms for halting giant planet migration.
| Radial velocities in selected B-G stars
Spectroscopic observations of a sample of nearby B-G stars are reported.The observations were obtained at resolution 19 km/s in the spectralregion near the 448.1228-nm line of Mg II using a CCD-detectorspectrograph on the coude-feed telescope at KPNO on April 16-20, 1986.The data are presented in extensive tables and briefly characterized.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Yilanci |
| Sað Açýklýk: | 16h32m08.08s |
| Yükselim: | -12°25'53.9" |
| Görünürdeki Parlaklýk: | 6.985 |
| Uzaklýk: | 145.985 parsek |
| özdevim Sað Açýklýk: | -22.1 |
| özdevim Yükselim: | -8.2 |
| B-T magnitude: | 7.133 |
| V-T magnitude: | 6.998 |
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