TIC 446502638
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 1.1080-day period, a 0.70% primary eclipse, a 0.25% secondary eclipse at phase 0.505. Automated cross-checks question this period - see below.
- Surface brightness ratio
- 0.36
- Companion temperature
- ~2,702 K
- Companion / star radius
- ~0.08
- Face hidden at primary eclipse
- ~1%
- Separation
- ~3.2 x the star's radius
- Eccentricity
- consistent with circular
- Secondary eclipse phase
- 0.505 measured, 0.500 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 follow temperature on a stellar colour scale, saturated so the differences show; the star's is its catalogue value (3,188 K). 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 3,989x 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 17:33 UTC
- Primary2026-10-20 06:42 UTC
- Secondary2026-10-20 20:08 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 0.815% (observed minus binned median).
Automated cross-checks question this period - see Caveats below.
- Period
- 1.10796 d
- Primary depth
- 0.70%
- Secondary depth
- 0.25%
- Epoch (T0)
- 3480.652 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 80.
- 6.1
- 0.16 px3"
- 0.0300 phase
- TIC 17489771770.25 px, dT 6.6
- 0.56
- 80
The dimming centroid sits almost as close to a bright neighbour as to the target.
- Centroid offset
- 0.16 px
- Difference SNR
- 6.1
- Capable neighbour
- TIC 1748977177
- TESS sector
- 80
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.
It is about 88 light years away: the light TESS recorded left it around 88 years ago.
Together the two stars give off about 539.0 times less light than the Sun in Gaia's band, before correcting for interstellar dust.
Its colour is redder than the Sun's, which usually means cooler - though dust along the way also reddens light.
Source: ESA Gaia DR3, source 4197552906559966848.
Gaia's measurements fit a single point of light well (RUWE 1.17), as expected for a pair too close for Gaia to separate.
- Distance
- 27 +/- 0 pc
- Light-travel time
- ~88 years
- Apparent G
- 13.66
- Absolute G
- 11.50
- Colour BP-RP
- 2.98
- RUWE
- 1.17
- Match offset
- 1.65 arcsec
The ground-survey check
An independent instrument, different years: does real ZTF photometry show the eclipse at the period TESS measured?
- ZTF g (394 pts, 83 outliers)Not significant (p=0.33)
- ZTF i (38 pts, 0 outliers)Too few outliers to test
- ZTF r (635 pts, 33 outliers)Not significant (p=0.17)
Folded at the TESS-measured period of 1.10796 d, no band shows a phase cluster tight enough to rule out chance. Ground-survey cadence is sparse - a handful of epochs per orbit - so this is the expected outcome for most real eclipses, not evidence against this one.
Source: ZTF public light-curve archive (IRSA), independent of the TESS data used to detect this candidate.
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
- 1.10796 d
- BLS period
- 1.10796 d
- Odd/even z
- 0.18
Caveats
Known limitations and things to check.
Cross-check:No eclipse at 7 of 16 covered epochs where the 1.10796 d period predicts one (each under half the typical depth, > 5 sigma below it). The period is probably wrong - the dips seen may be separate eclipses of a longer-period system.
- Thin margin:The ON_TARGET call rests on a neighbour-competition margin of just 0.090 px (dimming centroid 0.158 px from target vs 0.247 px from the nearest bright-enough neighbour) - inside diag_pixel.py's own stated centroid systematic of 0.10-0.3 px. TESS's resolution cannot confidently separate this star from that neighbour.
VIIIInstrument
Raw values, fits and technical details.
Instrument
Raw values, fits and technical details.
Full statistics
- 1.10796 d
- 1.10796 dsame
- 0.70% +/- 0.10%seen 1/16
- ML screening score
- 0.487logistic_regression
- 0.25% +/- 0.03%phase 0.505, 9 sigma
- 0.18< 3
- 0.5545 dpower 0.01
- 2.9 h
- Distance (TIC, Gaia-based)
- 27 pc+/- 0
- 13.69 / 12.33
- 3188 K / 0.24 Rsun
- RA / Dec (J2000)
- 19h 10m 45.6s -13d 18m 4s
- 12.5 / 6.1
- 12,137 ptsover 26 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 = 0.18 (gate 3.0): alternate eclipses match, so the BLS period stands.