TIC 330901906
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 3.7321-day period, a 0.68% primary eclipse, no significant secondary eclipse.
- Surface brightness ratio
- companion faint - no secondary eclipse
- Companion / star radius
- ~0.08
- Face hidden at primary eclipse
- ~1%
- Separation
- ~5.3 x the star's radius
- Eccentricity
- consistent with circular
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 13,435x 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 08:04 UTC
- Primary2026-10-21 04:51 UTC
- Secondary2026-10-23 01:38 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 0.588% (observed minus binned median).
Clear, repeating eclipses with a consistent period and depth.
- Period
- 3.73207 d
- Primary depth
- 0.68%
- Epoch (T0)
- 1740.915 BTJD
- Duration
- 5.86 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 56.
- 87.2
- 0.18 px4"
- 0.0075 phase
- TIC 20091255290.25 px, dT 4.3
- 0.77
- 56
The dimming centroid sits almost as close to a bright neighbour as to the target.
- Centroid offset
- 0.18 px
- Difference SNR
- 87.2
- Capable neighbour
- TIC 2009125529
- TESS sector
- 56
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 2,426 light years away: the light TESS recorded left it around 2,426 years ago.
Together the two stars give off about 3.8 times the Sun's light in Gaia's band - before correcting for interstellar dust, which only makes distant stars look fainter.
Its colour is close to the Sun's.
Source: ESA Gaia DR3, source 1973346123131237376.
Gaia's position measurements fit this source poorly (RUWE 16.02, above the usual 1.4). That often means more than one star is there - most likely a wider third star or an unresolved neighbour, since a tight eclipsing pair barely moves Gaia's image. Context, not confirmation.
- Distance
- 744 +/- 99 pc
- Light-travel time
- ~2,426 years
- Apparent G
- 12.56
- Absolute G
- 3.21
- Colour BP-RP
- 0.79
- RUWE
- 16.02
- Match offset
- 0.33 arcsec
The ground-survey check
An independent instrument, different years: does real ZTF photometry show the eclipse at the period TESS measured?
- ZTF g (744 pts, 0 outliers)Too few outliers to test
- ZTF r (553 pts, 3 outliers)Not significant (p=0.04)
Folded at the TESS-measured period of 3.73207 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
- 3.73207 d
- BLS period
- 3.73207 d
- Odd/even z
- 0.36
Caveats
Known limitations and things to check.
- Thin margin:The ON_TARGET call rests on a neighbour-competition margin of just 0.066 px (dimming centroid 0.182 px from target vs 0.248 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
- 3.73207 d
- 3.73207 dsame
- 0.68% +/- 0.06%seen 22/29
- ML screening score
- 0.512logistic_regression
- < 0.11%none at 5 sigma
- 0.36< 3
- 0.6219 dpower 0.01
- 5.9 h
- Distance (TIC, Gaia-based)
- 692 pc
- 12.57 / 12.15
- - / -
- RA / Dec (J2000)
- 21h 59m 6.8s +45d 15m 16s
- 60.1 / 87.2
- 34,792 ptsover 1846 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
22 eclipses timed, rms 19.38 min, reduced chi-square 196.41 (20 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 = 3.731581 +/- 0.000003 d.