Variable Stars - EPIC 204278916
Type T Tauri (TTS/ROT) Click for lightcurve TTS: when their properties are well-known, they are classified in two sub-groups: CTTS (Classical) and WTTS (Weak-lined).  GCVS types IT and INT. ROT: 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 Notice 574:  25 April 2017 Dr. Carlo Manara (ESA Science and Technology SCI-S, the Netherlands) and colleagues have requested AAVSO assistance in monitoring the young, disk-bearing low- mass (M type) pre-main-sequence star EPIC 204278916 (2MASS J16020757-2257467). Dr. Manara reports that this star showed "a very interesting dimming event in August-September 2014 which may be caused by transiting material (exo-comets like), as we discussed in: https://ui.adsabs.harvard.edu/#abs/2016MNRAS.tmp.1267S/abstract. It would be very useful to know whether this event has any periodicity in order to constrain the possible scenario.  The major dimming (up to 65%) we see is ~1.2 mag in V, others are ~0.5-0.8 mag" in V. He also notes that "the dimming event we saw lasted for some ~25 days, although the most extreme event was ~1 day long. Based on the noisy WASP data we have there are some suggestions that the event happens every ~100 days, but we are not sure about it." Dr. Manara requests ongoing monitoring of this system to look for additional dimming events and to observe any that are seen, so that he and his colleagues may determine if periodicity exists in these events and to study its nature. Beginning now and continuing until further notice, nightly observations - one to a few observations per night - in V are requested. Weekly observations in B are also requested. If a dimming event occurs, observations in V and B at a higher cadence are requested.
Hills Observatory: 1 January 2013 to 6 May 2018
COMETS COMETS
DEEP SKY DEEP SKY