J/A+A/320/185 J/A+A/320/185 UBVRIcJHKL photometry in Lup R Wichmann J Krautter E Covino J M Alcala R Neuhaeuser J H M M Schmitt Astron. Astrophys. 320 185 1997 1997A&A...320..185W Photometry, UBVRIJKLMNH Stars, pre-main sequence stars: formation stars: late-type stars: pre-main sequence X-rays: stars In a recent study, some 130 new weak-line T Tauri stars (WTTS) have been discovered in the Lupus star forming region (SFR). Some of these stars are seen projected onto regions of high obscuration, while others are located far from the Lupus dark clouds. In this paper we present photometric observations of a large sample of these WTTS. We estimate effective temperatures and luminosities for the stars observed, and derive masses and ages by comparison with theoretical evolutionary tracks. The mean age of WTTS seen in projection against the dark clouds is found to be lower than the mean age of WTTS discovered far from regions of high obscuration, and yet higher than the mean age of the classical T Tauri stars (CTTS) in Lupus. Moreover, while the CTTS in Lupus show an unusual predominance of very low-mass stars, the WTTS population in Lupus contains many stars with comparatively higher masses. Correlations between the X-ray emission and other stellar parameters, like bolometric luminosity, radius, mass, and age, are studied, and the results are discussed. For a description of the UBV, (RI)c and JHKL photometric systems, see e.g. <GCPD/01>, <GCPD/54> and <GCPD/09>

Star Identifier of star from ROSAT --- Vmag V magnitude mag B-V B-V color index mag U-B U-B color index mag V-Rc V-R(Cousin) color index mag V-Ic V-I(Cousin) color index mag Jmag J magnitude mag e_Jmag Error of J magnitude 0.01mag Hmag H magnitude mag e_Hmag Error of H magnitude 0.01mag Kmag K magnitude mag e_Kmag Error of K magnitude 0.01mag Lmag L magnitude mag e_Lmag Error of L magnitude 0.01mag Star Identifier of star --- SpType Spectral type --- Teff Effective temperature K log(L) Log(L_bol) solLum AV Extinction A(V) mag Rad Radius Sun Mass Mass number=1 Masses and ages are from evolutionary tracks by D'Antona and Mazzitelli (1994ApJS...90..467D) solMass l_log(age) Lower limit indicator number=2 U indicates that age is lower limit, otherwise blank --- log(age) Log(age) number=1 Masses and ages are from evolutionary tracks by D'Antona and Mazzitelli (1994ApJS...90..467D) yr D(H-K) Delta (H-K) mag Patricia Bauer CDS 1996Oct09Rainer Wichmann <R.Wichmann@lsw.uni-heidelberg.de> J_A+A_320_185.xml