Astron. Astrophys. Suppl. Ser. 145, 187-195

Photometric observations of weak-line T Tauri stars

II. $\vec wtts$  in Taurus-Auriga, Orion and Scorpius OB2-2

C. Chavarría-K¹ - L. Terranegra² - M.A. Moreno-Corral¹ - E. de Lara¹

Send offprint request: e-mail: chavarri@astrosen.unam.mx

1 - Instituto de Astronomía, Carretera Tijuana Ensenada km 107, Ensenada B.C., CP. 22860, México
2 - Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli, Italy

Received March 25, 1999; accepted April 11, 2000

Abstract:

We present uvby-$\beta$ photometry of 116 X-ray flux-selected active stars in the directions of the Orion (40), Taurus-Auriga (58) and Scorpius OB2-2 (18) star forming regions. Additionally, we give near IR JHK  photometry of 20 active stars in the Taurus-Auriga direction. The program stars were selected from the ROSAT All Sky Survey and EINSTEIN X-ray surveys and are spectroscopically confirmed weak-line T Tauri stars and weak-line T Tauri star candidates. The photometry confirms the young nature of the program stars and also indicates that a significant fraction of the sample could be foreground objects. The data given here probably represent the largest homogeneous uvby-$\beta$ photometric sample of new WTTS and WTTS candidates. Many objects in the sample are observed photometrically for the first time.

Key words: stars: activity -- stars: evolution -- stars: pre-main sequence