AAVSO: American Association of Variable Star Observers

Contributions of the AAVSO to Year 1 of TESS (Abstract)

Volume 47 number 2 (2019)

Dennis Conti
AAVSO, 49 Bay State Road, Cambridge, MA 02138
Stella Kafka
AAVSO, 49 Bay State Road, Cambridge, MA 02138


(Abstract only) This poster depicts contributions that the American Association of Variable Star Observers (AAVSO) and its members have made during the first year of TESS’ operation. With its well-known legacy and contributions in the area of variable star observing, the AAVSO added in early 1996 an additional focus, that of exoplanet observing. This was done in recognition of the valuable data such amateur astronomers were providing in helping to candidate exoplanets, as well as in the refinement of the ephemerides of known exoplanets. An AAVSO Exoplanet Section was thus established at that time to provide a “home” for such observers where they could be trained in “best practices,” share ideas, and foster communication with the professional community. Over 125 AAVSO members have since completed an Exoplanet Observing Course that covers such best practices, as well as an introduction to the astroimagej (aij) software. When TESS began its science operation this past year, a cadre of AAVSO members were then well-trained to participate in TESS’ Follow-up Program (TFOP) Subgroup-1 (SG1), the “Seeing Limited Subgroup.” With SG1’s primary objective being to help in the confirmation of candidate exoplanets, especially by ruling out false positives, AAVSO members have and continue to contribute to this objective. This poster depicts where in the TESS pipeline these observations are made, as well as examples of some of the methods used to identify true exoplanet transits from false positives. Because systems such as near-by eclipsing binaries (NEBs) can contaminate TESS’ relatively large aperture, a means was needed to reliably eliminate stars near a TESS target that, when blended with the target, could mimic an exoplanet transit. For example, it was found that for some targets, there could potentially be hundreds of near-by stars that needed to be cleared as potential false positives. In order to automate what was a manual process that could take an hour or more and to provide a more comprehensive analysis using Gaia’s Data Release 2 data, the AAVSO liaison to SG1, Dennis Conti, developed an add-on to aij that completed this evaluation in minutes. This poster then also displays this automated “NEB clearing” process.