Skip to main content


Alert Notice 574: Monitoring of EPIC 204278916 requested

April 25, 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).

The YSO Zoo

...and welcome to the Zoo!

Part of the reason why a YSO section is needed is to try and make some sense of how the different types of variable star fit into some sort of scheme. Should we view the various types as distinct, or should we look at behaviour instead? Pursuing the zoo theme for a while, how do the various types of YSO fit into the interstellar ecosystem?

The What and Why of YSO's!

This page will present a brief introduction to Young Stellar Objects and Star Formation. What it is and why we are so darn interested by the whole thing - and what we, as amateur astronomers, can do in helping to discover more about the amazing, violent processes that are going on, as you read this, in deepest space (at least that's what most of us are; apologies to you lucky visitors who actually get paid for doing astronomy)

Special Notice #209: Nightly monitoring of TW Hya in support of HST observations

May 17, 2010: Dr. Michael Sitko (U. Cincinnati) requests observations of the young stellar object TW Hya in support of upcoming Hubble Space Telescope observations. TW Hya is believed to be a T Tauri star that varies between magnitudes 10.5 and 12.2. TW Hya will be observed with the HST STIS instrument as part of a larger program to study the properties of potentially planet-forming disks around young stars. The star will be observed in the ultraviolet to search for time-variability in the gas in the inner accretion disk.

Alert Notice 488: Observations of AA Tau requested to schedule XMM-Newton

August 1, 2013: Dr. Hans Moritz Guenther (Harvard-Smithsonian Center for Astrophysics) has requested nightly observations of the classical T Tauri star AA Tau in order to schedule x-ray observations with XMM-Newton that have been planned for between 2013 August 15 and September 15.

Alert Notice 478: Transformed photometry of young stars in Cha requested

January 16, 2013: Dr. Péter Ábrahám (Konkoly Observatory, Budapest, Hungary) has requested the assistance of AAVSO observers in monitoring eight young stars in Chamaeleon in support of photometry he and his colleagues will be obtaining with the VLT/ISAAC (infrared) and Herschel Space Observatory (far-infrared) during January-February 2013.

Special Notice #235: Request for archival data: V1647 Ori and McNeil's Nebula

February 15, 2011: Dr. Colin Aspin (U. Hawaii) has requested archival images and other observations of the FU Orionis variable V1647 Ori and the surrounding field over the previous 10 years in support of a study of this star.  Aspin writes that he is hoping to obtain more data with which to create a multi-year light curve of this star to put present-day observations in context of its past behavior.

Alert Notice 427: Observing campaign on BM Ori and the Trapezium region

November 23, 2010: The AAVSO requests ground-based observations of the Trapezium region of the Orion Nebula (M42), along with surrounding regions in Orion, in conjunction with upcoming observations with the MOST Satellite.  All AAVSO observers are encouraged to participate in this project, and we are requesting observations for a number of different targets from both instrumental and visual observers.


AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484