TIC 313684677
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 3.3166-day period, a 1.00% primary eclipse, no significant secondary eclipse.
- Surface brightness ratio
- companion faint - no secondary eclipse
- Companion temperature
- below ~4,095 K
- Companion / star radius
- ~0.10
- Face hidden at primary eclipse
- ~1%
- Separation
- ~6.9 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 follow temperature on a stellar colour scale, saturated so the differences show; the star's is its catalogue value (6,650 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 11,940x 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.
- Primary2026-10-19 06:48 UTC
- Secondary2026-10-20 22:36 UTC
- Primary2026-10-22 14:24 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 46919152386132.445% (observed minus binned median).
Clear, repeating eclipses with a consistent period and depth.
- Period
- 3.31659 d
- Primary depth
- 1.00%
- Epoch (T0)
- 1599.913 BTJD
- Duration
- 4.08 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 11.
- 13.1
- 0.12 px3"
- 0.0050 phase
- TIC 3136846820.17 px, dT 1.6
- 1.00
- 11
The dimming centroid sits almost as close to a bright neighbour as to the target.
- Centroid offset
- 0.12 px
- Difference SNR
- 13.1
- Capable neighbour
- TIC 313684682
- TESS sector
- 11
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 4,318 light years away: the light TESS recorded left it around 4,318 years ago.
Together the two stars give off about 8.0 times the Sun's light in Gaia's band - before correcting for interstellar dust, which only makes distant stars look fainter.
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 5868723268372353920.
Gaia's measurements fit a single point of light well (RUWE 0.98), as expected for a pair too close for Gaia to separate.
- Distance
- 1,324 +/- 23 pc
- Light-travel time
- ~4,318 years
- Apparent G
- 13.02
- Absolute G
- 2.41
- Colour BP-RP
- 0.97
- RUWE
- 0.98
- Match offset
- 0.21 arcsec
The ground-survey check
An independent instrument, different years: does real ZTF photometry show the eclipse at the period TESS measured?
No ZTF observations at this position (declination -61.0 deg) - likely too far south for ZTF's footprint, which covers the sky north of roughly -31 deg. Not a mark against the candidate, just a gap in ground-survey coverage.
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
- 3.31659 d
- BLS period
- 3.31659 d
- Odd/even z
- 0.96
Caveats
Known limitations and things to check.
- Thin margin:The ON_TARGET call rests on a neighbour-competition margin of just 0.049 px (dimming centroid 0.121 px from target vs 0.169 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
- 3.31659 d
- 3.31659 dsame
- 1.00% +/- 0.05%seen 7/7
- ML screening score
- 0.505logistic_regression
- < 0.17%none at 5 sigma
- 0.96< 3
- 13.5313 dpower 0.01
- 4.1 h
- Distance (TIC, Gaia-based)
- 1373 pc+/- 37
- 13.03 / 12.52
- 6650 K / 3.27 Rsun
- RA / Dec (J2000)
- 13h 28m 12.1s -60d 58m 59s
- 83.1 / 13.1
- 1,081 ptsover 27 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 = 0.96 (gate 3.0): alternate eclipses match, so the BLS period stands.
O - C timing
6 eclipses timed, rms 3.34 min, reduced chi-square 1.70 (4 dof): consistent with a constant period.
Each eclipse timed by fitting the star's own mean eclipse profile; fitted P = 3.316769 +/- 0.000423 d.