I'm an amateur astronomer working on a project to analyze public data from the TESS mission, and I think I've identified a potential transit signal from a candidate exoplanet around a faint M-dwarf star. My light curve analysis shows a periodic dip, but I'm struggling to rule out instrumental artifacts or stellar variability with the tools I have. I'd love to get a second opinion on my methodology and learn what the next steps would be to contribute this finding to a citizen science database or even for professional follow-up.
Nice catch. A solid next step is to rule out artifacts and stellar variability. Check if the dip repeats in multiple sectors with the same depth and epoch, and run a centroid analysis to confirm the transit comes from your target star rather than a background source. Do an odd-even test: if those depths differ, that points to an eclipsing binary rather than a planet. Look for a secondary eclipse at phase 0.5 as another red flag.
Here’s a practical workflow you can try: pull the light curves for all sectors containing the star (TESS data, ideally in the same aperture). Detrend with cotrending basis vectors, fold on the candidate period, and fit a Mandel-Agol transit with BATMAN to get depth, duration, and t0. Compare the transit depth stability across sectors and check for centroid motion tied to the transit phase. Cross-match the target with Gaia DR3 to rule out a nearby star within the TESS pixel. If you can, quantify the false-positive probability with a simple model comparison (planet vs EB vs noise).
To push validation, plan some follow-up: ground-based transit photometry at predicted times (in multiple bands if possible), high-resolution imaging to search for close companions, and, if feasible, a spectroscopic constraint to rule out a stellar companion (or at least a velocity constraint). Multi-band transit depth consistency helps; EB scenarios often show color dependence. If a neighbor is found, use centroid shifts to confirm the source.
Citizen-science path and professional workflow: you can submit to Planet Hunters TESS (Zooniverse) to crowd-test the light curve, or submit to the Exoplanet Archive as a candidate with all your validation tests documented. For professional follow-up, prepare a concise evidence package: stellar parameters, period and epoch, transit depth and duration, SNR, validation tests (odd-even, centroid, multi-sector consistency), data provenance, and accessibility of data.
Could you share a few details so I can tailor a plan? What is the star's TIC ID and magnitude? How many transits have you seen, and in which sectors? Do you have centroid results or Gaia neighbors within the aperture? Are you seeing any wavelength-dependent depth if you have multi-band data? Do you have ground-based observatories or collaborators who could do follow-up?