TIC 40208362
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 0.6908-day period, a 2.75% primary eclipse, a 2.45% secondary eclipse at phase 0.598. Automated cross-checks question this period - see below.
TIC 40208362 is a candidate eclipsing binary star with an orbital period of 0.6908 days. The primary eclipse produces a 1.63% dimming of the star's light, detected with a signal-to-noise ratio of 240.1 in automated TESS photometry. Pixel-level analysis shows a difference-imaging peak signal-to-noise of 15.9, though the centroid offset of 7.2 arcsec from the target warrants further investigation. No secondary eclipse was detected in the available data. The candidate does not appear in six major variable-star catalogs, making it a potentially new addition to the known population. The machine-learning screening score of 0.92 indicates strong agreement with the pipeline's model for authentic eclipsing systems, and the data passed all quality checks without flagged issues.
This light curve is smooth and sinusoidal rather than eclipse-shaped - typical of a close pair distorted by each other's gravity, or of a signal that is not an eclipse - so the eclipse-geometry estimates do not apply. The drawing is generic; the glow still follows the real light curve.
Not to scale. 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 follow temperature on a stellar colour scale, saturated so the differences show; the star's is its catalogue value (6,375 K). Only the relative orbit is shown; both stars really circle their common centre of mass. Animated about 2,487x 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 08:53 UTC
- Primary2026-10-19 15:32 UTC
- Secondary2026-10-20 01:28 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 0.297% (observed minus binned median).
Automated cross-checks question this period - see Caveats below.
- Period
- 0.69082 d
- Primary depth
- 2.75%
- Secondary depth
- 2.45%
- Epoch (T0)
- 1711.502 BTJD
- Duration
- 0.96 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 41.
- 15.9
- 0.34 px7"
- 0.2000 phase
- TIC 402083481.33 px, dT 4.3
- 0.82
- 41
The dimming is centred on the target star. No nearby contaminant detected.
- Centroid offset
- 0.34 px
- Difference SNR
- 15.9
- Capable neighbour
- TIC 40208348
- TESS sector
- 41
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
- 0.69082 d
- BLS period
- 0.69082 d
- Odd/even z
- 1.22
Caveats
Known limitations and things to check.
Cross-check:The light curve is dominated by a smooth sinusoid with period 0.13819 d (Lomb-Scargle power 0.88); the adopted 0.69082 d is 5.00 x that. The true period is more likely 0.13819 d (pulsation or spots) or 0.27638 d (contact binary), and the 'eclipses' may not be eclipses.
VIIIInstrument
Raw values, fits and technical details.
Instrument
Raw values, fits and technical details.
Full statistics
- 0.69082 d
- 0.69082 dsame
- 2.75% +/- 0.04%seen 36/36
- ML screening score
- 0.919logistic_regression
- 2.45% +/- 0.07%phase 0.598, 34 sigma
- 1.22< 3
- 0.1382 dpower 0.88 - FLAG
- 1.0 h
- Distance (TIC, Gaia-based)
- 697 pc+/- 48
- 11.56 / 11.16
- 6375 K / 2.66 Rsun
- RA / Dec (J2000)
- 20h 01m 50.0s +38d 23m 22s
- 240.1 / 15.9
- 4,384 ptsover 735 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 = 1.22 (gate 3.0): alternate eclipses match, so the BLS period stands.
O - C timing
36 eclipses timed, rms 0.73 min, reduced chi-square 1.74 (34 dof): consistent with a constant period.
Each eclipse timed by fitting the star's own mean eclipse profile; fitted P = 0.690966 +/- 0.000006 d.