1997A&A...326..647F


Query : 1997A&A...326..647F

1997A&A...326..647F - Astronomy and Astrophysics, volume 326, 647-654 (1997/10-2)

On the widespread weak-line T-Tauri population detected in the ROSAT All-Sky Survey.

FAVATA F., MICELA G. and SCIORTINO S.

Abstract (from CDS):

We discuss the apparent widespread presence of Weak-Line T-Tauri stars (WTTS) among stellar coronal sources detected in the ROSAT All-Sky Survey (RASS), and their relative number with respect to young main-sequence stars in the same samples. The approach taken in most of the current literature for identifying and classifying WTT stars among RASS X-ray sources is based on the usage of low-resolution optical spectra only and on simple, mass-independent thresholds on the equivalent width of the LiI 6707.8Å doublet. We show that this approach is likely to lead to putative WTTS samples which contain a large number of normal, young main-sequence stars masquerading as WTTS sources. Young main-sequence stars are known to be the dominant contributor in stellar X-ray selected samples at the limiting flux levels of the RASS, yet they appear to be very rare in the RASS samples discussed here. We argue that many of the putative WTTS sources are actually mis-classified young main-sequence stars, and that thus there is likely not a true ``WTTS question'' in the RASS samples.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: late-type - stars: pre-main sequence - X-rays: stars

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 17925 RS* 02 52 32.1281856011 -12 46 10.968056223 7.48 6.91 6.05 5.34 4.89 K1V 486 0
2 V* AK For EB* 03 29 22.8752567640 -24 06 03.098788272   10.46 9.36     K3VkFe+0.4 38 0
3 HD 25300 * 03 59 36.7302091392 -39 53 14.875717992   11.21 10.02     K0 19 0
4 HD 26913 BY* 04 15 25.7871375264 +06 11 58.751401236 7.790 7.580 6.920 6.554 6.195 G8V 210 0
5 HD 26923 PM* 04 15 28.8004060272 +06 11 12.698572488 6.910 6.860   5.9   G0IV 200 0
6 V* V1005 Ori BY* 04 59 34.8342878424 +01 47 00.669818328   11.48 10.107 9.603 8.239 M0Ve 322 0
7 V* V1402 Ori Er* 05 40 16.0930339920 +12 39 00.622253052   12.61 11.354 10.963 9.207 M1.5V 44 0
8 HD 47875 Ce* 06 34 40.9887640488 -69 53 06.152733708   9.84 9.17     G4V 29 0
9 HD 48189 BY* 06 38 00.3532489704 -61 32 00.114167796   6.747 6.182   5.46 G1/2V 133 0
10 * mu. Vel ** 10 46 46.17877 -49 25 12.9244 4.16 3.59 2.69 2.01 1.52 G6III 177 0
11 V* V1150 Sco Ro* 15 59 59.9527097064 -22 20 36.759121188     11.99   10.90 M1V 29 0
12 V* V1151 Sco BY* 16 01 05.1852470424 -22 27 31.320270432   15.23 13.69 13.38 11.14 M3Ve 31 0

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2022.05.22-21:23:48

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