TypeT Tauri StarWhen their properties are well-known, T Tauri stars are classified in two sub-groups: CTTS (Classical) and WTTS (Weak-lined). GCVS types IT and INT.T Tauri stars showing periodic variability due to spots. For those members of this class where special features are well known, the subtype classifications of CTTS/ROT or WTTS/ROT may be applied. Where not precisely known, the subtype of TTS/ROT is used.AAVSO Alert 494: December 19, 2013Darryl Sergison (University of Exeter) has requested AAVSO assistance with a campaign he is carrying out on five T Tauri stars. This study is the one for which AAVSO observers carried out a preliminary campaign last year (see Alert Notice 473 and Special Notice #306). The star list is revised and expanded from last year's list of targets. This campaign will run from now at least through the end of the 2013-2014 observing season.This is part of an on-going study into the nature of pre-main-sequence low mass stars, using time series optical spectroscopy and UV-Visual-IR photometry and offers a great opportunity for professional-amateur collaboration as the objects (with V magnitudes of 10 - 13) are well within the reach of photometry by small telescopes. Amateur observations are uniquely useful in the study of chaotically variable young stars as they offer crucial datapoints in the light curve between observations made by professional telescopes.