TIC 258151016
An uncatalogued eclipsing-binary candidate from TESS.
Eclipsing-binary candidate: 0.8940-day period, a 4.12% primary eclipse, no significant secondary eclipse. Automated cross-checks question this period - see below.
TIC 258151016 is a candidate eclipsing binary star with an orbital period of 0.8940 days. Automated analysis of TESS photometry detected a primary eclipse causing 3.87% dimming, with a detection significance of 114.5 in the box-least-squares search. Pixel-level image analysis confirmed the signal's location within 0.6 arcsec of the target star, with a peak signal-to-noise ratio of 73.4 in difference imaging. No secondary eclipse was detected. The candidate does not appear in six major variable-star catalogs, making it a novel target. The pipeline's machine-learning model assigned it a screening score of 0.29, and the photometric data passed all quality checks without flagged issues.
- Surface brightness ratio
- companion faint - no secondary eclipse
- Companion / star radius
- ~0.20
- Face hidden at primary eclipse
- ~4%
- Separation
- ~2.9 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 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 3,219x 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 07:51 UTC
- Secondary2026-10-19 18:35 UTC
- Primary2026-10-20 05:18 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 112.589% (observed minus binned median).
Automated cross-checks question this period - see Caveats below.
- Period
- 0.89405 d
- Primary depth
- 4.12%
- Epoch (T0)
- 1518.367 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 8.
- 73.4
- 0.03 px1"
- 0.0025 phase
- TIC 2581510311.41 px, dT 2.1
- 0.97
- 8
The dimming is centred on the target star. No nearby contaminant detected.
- Centroid offset
- 0.03 px
- Difference SNR
- 73.4
- Capable neighbour
- TIC 258151031
- TESS sector
- 8
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
- 0.89405 d
- BLS period
- 0.89405 d
- Odd/even z
- 0.24
Caveats
Known limitations and things to check.
Cross-check:No eclipse at 1 of 20 covered epochs where the 0.89405 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.
VIIIInstrument
Raw values, fits and technical details.
Instrument
Raw values, fits and technical details.
Full statistics
- 0.89405 d
- 0.89405 dsame
- 4.12% +/- 0.20%seen 18/20
- ML screening score
- 0.287logistic_regression
- < 0.41%none at 5 sigma
- 0.24< 3
- 12.2811 dpower 0.06
- 2.9 h
- Distance (TIC, Gaia-based)
- -
- 14.84 / 14.40
- - / -
- RA / Dec (J2000)
- 08h 27m 47.1s -26d 27m 10s
- 114.5 / 73.4
- 862 ptsover 25 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 = 0.24 (gate 3.0): alternate eclipses match, so the BLS period stands.
O - C timing
18 eclipses timed, rms 6.36 min, reduced chi-square 5.89 (16 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 = 0.894997 +/- 0.000039 d.