Centimeter Radio Emission from Low-Mass Weak T Tauri Stars in Taurus-Auriga
Session 48 -- Young Stars
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

## [48.08] Centimeter Radio Emission from Low-Mass Weak T Tauri Stars in Taurus-Auriga

Eugene Chiang (MIT), R.B.Phillips (MIT Haystack Observatory)

We report on the results of a sensitive survey for $\lambda$3.6 cm radio emission from low-mass, weak T Tauri (WTT) stars in the Taurus-Auriga cloud complex. The target population consists of stars in the Herbig and Bell Catalog of spectral type K7 or later, and $W$(H$\alpha$) $\leq$ 10 $\rm \AA$. Of the 28 such stars surveyed using the Very Large Array down to detection thresholds of $\sim$0.1 mJy, 7 (possibly 8) are observed to emit at strengths ranging from 0.1 to 2 mJy. Five of these young radio stars are newly discovered in our survey: V827 Tau and V710 Tau B are discovered to be relatively strong sources of mJy emission, while IW Tau, UX Tau B, and the possible detection LkHa 332-G1 form a new population of relatively weak emitters.

Our radio survey and complementary surveys are pooled, and of 43 WTT stars K7 or later in Tau-Aur, 14 are now known to be radio emitters at $\lambda$6 and $\lambda$3.6 cm. Correlations between radio luminosity and other stellar parameters have been attempted but generally yield null results. Wide binarity (component separations in excess of 0$''.$13, 20 AU) appears unrelated to radio emission, as does spectral type. Furthermore, we find no convincing evidence for the extreme youth of radio stars, contrary to claims in the literature over the past decade. While we do find that radio-loud stars in our sample are formally younger than the radio-quiet stars by about 0.5 Myr, the reality of this relatively small age difference is highly suspect given uncertainties in the placement of these stars on the HR diagram. Moreover, Monte Carlo-type calculations involving distributing the stars on both the HR diagram and local CO gas density cast doubts on any differences between the radio stars and the general WTT population. We conclude that the age effect for low-mass radio WTT stars in Tau-Aur, if real, is much smaller than previous estimations by factors of 4-10.

It is also possible centimeter wavelength surveys to date have still not properly described the radio luminosity function of low-mass WTT stars in Tau-Aur, and we urge future observations of these young stars with denser temporal coverage.