TIC 378434189
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 0.8113-day period, a 8.92% primary eclipse, a 7.70% secondary eclipse at phase 0.493.
TIC 378434189 is a candidate eclipsing binary star with an orbital period of 0.8113 days. The TESS photometry shows a primary eclipse with a depth of 5.96 percent dimming, detected with a signal-to-noise ratio of 96.2 using the box least-squares method. Pixel-level image analysis confirms the signal at the target location, with a peak difference-imaging signal-to-noise of 46.7 and a centroid offset of 1.3 arcseconds from the target. No secondary eclipse was detected. The candidate does not appear in six major variable-star catalogs, making it a novel find. The machine learning screening score of 0.37 indicates moderate confidence that this is a real stellar system rather than an artifact. No data quality issues were flagged during automated processing.
- Surface brightness ratio
- 0.86
- Companion / star radius
- ~0.31
- Face hidden at primary eclipse
- ~10%
- Separation
- ~2.9 x the star's radius
- Eccentricity
- at least 0.011
- Secondary eclipse phase
- 0.493 measured, 0.493 in this orbit
Zoomed: both stars drawn about 1x larger than their real size relative to the orbit, so they overlap for longer than the real eclipse lasts. A star's surface never gets dimmer during an eclipse - part of it is simply hidden. What drops is the total light we receive, shown exactly by the readout and bar below from the real light curve; the glow dims with it, exaggerated so small dips show. Colours are illustrative. The companion's colour, sizes and orbit shape are estimates from the eclipse depths, duration and timing, assuming central eclipses and spherical stars - good to perhaps tens of percent. Only the relative orbit is shown; both stars really circle their common centre of mass. Animated about 2,921x faster than real on average, slowing down through each eclipse, and starting from where the system is in its orbit right now. Hover to pause.
- Secondary2026-10-19 13:48 UTC
- Primary2026-10-19 23:40 UTC
- Secondary2026-10-20 09:16 UTC
Computed from the fitted ephemeris. Approximate - not corrected for your location or for light-travel time across Earth's orbit.
The signal
A repeating, consistent dip in brightness.
Residual scatter 4.197% (observed minus binned median).
Clear, repeating eclipses with a consistent period and depth.
- Period
- 0.81129 d
- Primary depth
- 8.92%
- Secondary depth
- 7.70%
- Epoch (T0)
- 1683.803 BTJD
- Duration
- 2.88 h
The catalog check
Cross-matched against known variable-star catalogs to rule out anything already listed.
- VSXNot found
- ASAS-SNNot found
- Gaia eclipsing-binary tableNot found
- Gaia variable classificationNot found
- TESS EB catalog (Prsa+2022)Not found
- ExoFOP TOI listNot found
0/6 catalogs list a known variable at this position.
No known variable star or catalogued match at this position.
- Catalogs checked
- 6
- Matches
- 0
The pixel check
Confirms the dimming is on the target star, not a nearby source.
Out/in share one sqrt colour scale; in-eclipse = out-of-eclipse minus difference. TESS sector 81.
- 46.7
- 0.06 px1"
- 0.0200 phase
- TIC 3784342010.23 px, dT -1.1
- 0.91
- 81
The dimming is centred on the target star. No nearby contaminant detected.
- Centroid offset
- 0.06 px
- Difference SNR
- 46.7
- Capable neighbour
- TIC 378434201
- TESS sector
- 81
The Gaia view
A second spacecraft's measurements: how far away the star is, how bright and what colour, and whether its position fits a single star.
The latest Gaia context file does not include this candidate yet, so there is no Gaia view to show.
The ground-survey check
An independent instrument, different years: does real ZTF photometry show the eclipse at the period TESS measured?
The latest ground-survey file does not include this candidate yet, so there is no independent ZTF check to show.
Fold it yourself
Adjust the period and watch the eclipse appear.
Shown at the true period. The raw light curve needed to re-fold at other periods has not been exported yet - this slider unlocks automatically once it is.
The period the pipeline measured. Drag the slider away from it and the eclipse smears out.
- True period
- 0.81129 d
- BLS period
- 0.81129 d
- Odd/even z
- 0.36
Caveats
Known limitations and things to check.
No caveats flagged: this candidate cleared every gate with no named exception. Follow-up observations would still be needed to confirm the stellar parameters.
VIIIInstrument
Raw values, fits and technical details.
Instrument
Raw values, fits and technical details.
Full statistics
- 0.81129 d
- 0.81129 dsame
- 8.92% +/- 0.07%seen 128/130
- ML screening score
- 0.368logistic_regression
- 7.70% +/- 0.04%phase 0.493, 208 sigma
- 0.36< 3
- 0.4057 dpower 0.36
- 2.9 h
- Distance (TIC, Gaia-based)
- 633 pc
- 13.55 / 12.89
- - / -
- RA / Dec (J2000)
- 19h 41m 26.9s +20d 56m 60s
- 96.2 / 46.7
- 23,440 ptsover 1850 d
Eclipse close-ups
Same flux scale on both panels. Line: binned median. Shown in place of an orbit animation - this pipeline measures eclipses, it does not fit an orbit.
Period alias analysis
Odd/even depth z = 0.36 (gate 3.0): alternate eclipses match, so the BLS period stands.
O - C timing
127 eclipses timed, rms 6.78 min, reduced chi-square 7.87 (125 dof): more scatter than the timing errors explain - worth a closer look.
Each eclipse timed by fitting the star's own mean eclipse profile; fitted P = 0.811320 +/- 0.000000 d.