Hi all!
I’m an independent researcher in Romania working on TESS light-curve analysis. I’ve been investigating an anomaly at TIC 427154884 (Tmag 12.1, catalogued cool giant, Teff ~4017 K, R ~30 R☉, ~4 kpc, crowded/reddened field), and I’d appreciate advice on whether it’s worth a spectrum.
QLP light curves across sectors 16, 17, 24, 56, 76, 77, 83 (2019–2024) show a clean ~14% peak-to-peak variation at P = 0.2479071 d (orbital 0.4958142 d if binary). A single ephemeris fits all seven sectors to ~0.001 cycle across both the 1800 s and 200 s cadences, and a per-pixel Lomb–Scargle map on the raw TESScut FFI localizes the signal to the target pixel, so it’s astrophysical, not a pipeline artifact. The period is far too short for the catalogued giant. Independent optical photometry does not detect the signal at the target: ZTF (~2″, injection-validated in g) and ATLAS forced photometry (o-band, 3023 epochs, the red band matched to TESS) both show no power at the period, and a 2MASS / AllWISE / Gaia search finds no resolved hidden source.
The evidence points to an unresolved (within ~0.7″), very-red, short-period variable blended with the giant, plausibly a foreground red-dwarf eclipsing/contact binary, though a genuinely single anomalous star can’t be excluded from photometry alone.
What would settle it is a single spectrum (composite / two-lined signature, or RV variation on the 0.2479 / 0.4958 d cycle), or sub-arcsecond near-IR imaging. Full analysis, figures, and methods are in the attached report and on ExoFOP-TESS (data tag 477311,(https://exofop.ipac.caltech.edu/tess/target.php?id=427154884).
Happy to answer questions or share the light curves. Any thoughts on feasibility for a small-telescope spectrograph, or pointers to who might be a good match
Thanks,
Munteanu Sabin.