JohnGavin/tess-qlp-s0098-prototype

TESS QLP Sector 98 prototype

This is a prototype. It is a random sample of 1,000 stars from TESS (Transiting Exoplanet Survey Satellite) Sector 98, taken from the Quick-Look Pipeline (QLP) full-frame-image light curves, run through a transit search to test how a whole sector's results can be hosted and read. It makes no claim of planet detections: the search peaks (signals) are candidates from an automated search and are not vetted. The threshold and calibration tables show how noisy that search is.

What is in it

Only cadences with QUALITY == 0 and finite time, flux and flux error are kept. 821 of the 1,000 stars were searched; 179 had no usable rows and appear in stars and manifest only. Flux is the detrended DET_FLUX column, not normalised. Row groups are 98,304 rows, zstd-compressed, so a reader can fetch one star's rows without the whole file.

File	Rows	Row groups	Meaning
stars.parquet	1,000	1	one row per sampled star: TIC id, TESS magnitude, radius, temperature, camera, CCD, position, search status, noise level, best signal-to-noise ratio (SNR), number of signals
signals.parquet	2,463	1	one row per star and BLS peak (top peaks of the box least squares search): period, mid-transit time, duration, depth, SNR, power, odd and even depths
events.parquet	28,392	1	one row per single transit of a signal: time, depth, points in transit, SNR
manifest.parquet	1,000	1	one row per sampled star: download and parse status, rows read and kept, timings
calibration.parquet	1,123	1	positive and negative controls and injection-recovery trials (synthetic transits added to real light curves)
threshold.parquet	14	1	summary of the best SNR found in inverted (flipped) light curves, where any dip is noise
quality_bits.parquet	36,318	1	rows per star, orbit and QUALITY flag bit (counts only; bit meanings are not stated)
cadences.parquet	9,908,365	101	full-resolution light curves of the stars with usable rows (200 s cadence), sorted by tic_id then time
cadences_10min.parquet	3,463,467	36	the same light curves averaged into 10-minute bins (n_points = cadences averaged), same ordering

No column held a local file path, so none was removed. MANIFEST.csv lists each file with its bytes, rows, row groups, SHA-256 and the sum of each numeric column (col_sums).

Schema

Column types are read from the files in this repository, not typed by hand. Times are BTJD (BJD - 2457000, days). "Empty" means a missing value.

stars.parquet

Column	Type	Meaning
tic_id	DOUBLE	TESS Input Catalog (TIC) identifier of the star
status	VARCHAR	download and parse status of the star's light-curve file (ok = read)
tessmag	DOUBLE	TESS magnitude (brightness in the TESS band; smaller is brighter)
radius	DOUBLE	stellar radius in solar radii, from the QLP file header (empty when unknown)
teff	DOUBLE	effective temperature in kelvin, from the QLP file header (empty when unknown)
camera	DOUBLE	TESS camera (1 to 4) that observed the star
ccd	DOUBLE	detector (1 to 4) within the camera
ra	DOUBLE	right ascension in degrees
dec	DOUBLE	declination in degrees
search_status	VARCHAR	outcome of the transit search: ok, no_good_rows (no usable rows), or the reason it was skipped
n_binned	INTEGER	number of binned points the search used (empty when not searched)
noise_ppm	DOUBLE	scatter of the binned flux in parts per million (robust standard deviation; empty when not searched)
flipped_best_snr	DOUBLE	best SNR found on the flipped (inverted) light curve, where any dip is noise
best_snr	DOUBLE	SNR of the strongest search peak (empty when no peak)
n_signals	INTEGER	number of search peaks kept for the star (rows in signals; 0 when none)
cad_offset	DOUBLE	byte position where the star's file starts in cadences_by_star.bin (empty when it has none)
cad_bytes	DOUBLE	length in bytes of the star's file in cadences_by_star.bin (empty when it has none)
cad_rows	DOUBLE	number of rows (cadences) in the star's file in cadences_by_star.bin (empty when it has none)

signals.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
rank	INTEGER	peak rank within the star, 1 = strongest
period	DOUBLE	orbital period of the peak in days
t0	DOUBLE	mid-time of a transit, in BTJD (BJD - 2457000, days)
duration	DOUBLE	transit duration in days
depth	DOUBLE	fractional dip in flux during transit
depth_err	DOUBLE	uncertainty of depth
snr	DOUBLE	signal-to-noise ratio (SNR) of the depth
power	DOUBLE	box least squares (BLS) power at the peak
depth_odd	DOUBLE	depth from odd-numbered transits only
depth_even	DOUBLE	depth from even-numbered transits only
odd_even_sigma	DOUBLE	difference of odd and even depths in standard errors (empty when either is undefined)

events.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
rank	INTEGER	rank of the signal this transit belongs to (matches signals.rank)
time	DOUBLE	predicted mid-time of the single transit, in BTJD (days)
depth	DOUBLE	fractional dip in flux measured in that transit (empty when no data fall in it)
n_in	INTEGER	number of binned points inside the transit window
snr	DOUBLE	SNR of that single transit's depth (empty when no data fall in it)

manifest.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
status	VARCHAR	ok, download_failed or parse_failed
bytes	DOUBLE	size in bytes of the downloaded light-curve file
rows_total	INTEGER	rows in the light-curve file
rows_kept	INTEGER	rows kept (QUALITY == 0 and finite time, flux and flux error)
seconds	DOUBLE	total seconds spent on the star
download_seconds	DOUBLE	seconds spent downloading
reduce_seconds	DOUBLE	seconds spent reading and reducing
tessmag	DOUBLE	TESS magnitude
radius	DOUBLE	stellar radius in solar radii (empty when unknown)
teff	DOUBLE	effective temperature in kelvin (empty when unknown)
camera	DOUBLE	TESS camera (1 to 4)
ccd	DOUBLE	detector (1 to 4) within the camera
message	VARCHAR	error text when the download or parse failed

calibration.parquet

Column	Type	Meaning
kind	VARCHAR	positive_control, negative_control, injection_recovery (synthetic transits added to a real light curve) or flipped (search on the inverted light curve)
tic_id	DOUBLE	TIC identifier of the star
inj_period	DOUBLE	period of the injected transit in days (empty for flipped rows)
inj_depth	DOUBLE	fractional depth of the injected transit (empty for flipped rows)
best_period	DOUBLE	period of the strongest peak the search then found, in days
best_snr	DOUBLE	SNR of that peak
recovered	BOOLEAN	TRUE when the found period matched the injected one within tolerance (empty for flipped rows)
seconds	DOUBLE	seconds the search took

threshold.parquet

Column	Type	Meaning
metric	VARCHAR	name of the summary statistic (counts, quantiles and maxima of best SNR)
value	DOUBLE	value of the statistic

quality_bits.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
orbit_id	INTEGER	orbit of the spacecraft the rows belong to
orbit_source	VARCHAR	where the orbit came from: ORBITID (file column) or time_gap (derived from gaps in time)
kind	VARCHAR	what is counted: rows_total, bit (one QUALITY flag bit), or another dropped-row category
bit	INTEGER	QUALITY flag bit number (empty unless kind is bit)
n_rows_with	INTEGER	rows in the orbit counted under this kind (for a bit: rows with that bit set)
n_rows_only	INTEGER	for a bit: rows where it is the only bit set (empty otherwise)
bit_meaning	VARCHAR	meaning of the bit (empty: the QLP file does not state one)
meaning_source	VARCHAR	source of the stated meaning (empty when none)

cadences.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
time	DOUBLE	time of the observation in BTJD (BJD - 2457000, days)
flux	DOUBLE	detrended QLP flux (DET_FLUX column) as delivered, not re-normalised
flux_err	DOUBLE	uncertainty of flux (DET_FLUX_ERR column)
quality	INTEGER	QLP QUALITY flag; always 0 here, because only QUALITY == 0 rows are kept

cadences_10min.parquet

Column	Type	Meaning
tic_id	DOUBLE	TIC identifier of the star
time	DOUBLE	mean time of the cadences in the bin, in BTJD (days)
flux	DOUBLE	mean flux of the cadences in the bin
flux_err	DOUBLE	uncertainty of the binned flux
n_points	INTEGER	number of cadences averaged into the bin

cadences_by_star.bin

Not a parquet file itself: each star is its own zstd-compressed parquet file with the columns time, flux, flux_err (same meaning as in cadences.parquet), laid end to end in ascending tic_id order. In stars.parquet, cad_offset, cad_bytes and cad_rows give a star's byte range and row count; the 179 stars with search_status no_good_rows have no range (those three columns are empty). Rows within a star are ordered by time.

Column	Type	Meaning
time	DOUBLE	time of the observation in BTJD (BJD - 2457000, days)
flux	DOUBLE	detrended QLP flux (DET_FLUX column) as delivered, not re-normalised
flux_err	DOUBLE	uncertainty of flux (DET_FLUX_ERR column)

Read one star

-- DuckDB
SELECT time, flux, flux_err
FROM 'hf://datasets/JohnGavin/tess-qlp-s0098-prototype/cadences.parquet'
WHERE tic_id = 201374538
ORDER BY time;

Read one star in a single request

cadences_by_star.bin holds each of the 821 stars' light curves (time, flux, flux_err) as its own small parquet file, laid end to end in tic_id order. In stars.parquet, cad_offset is where a star's file starts, cad_bytes its length in bytes and cad_rows its row count (all three are empty for a star with no usable rows). A reader takes those two numbers from the stars table it already has and sends one HTTP request, Range: bytes=<cad_offset>-<cad_offset + cad_bytes - 1>, then opens the returned bytes as a parquet file. It saves the several round trips a reader needs to find one star inside cadences.parquet. The rows are the same as in cadences.parquet; the file is 80,988,209 bytes.

Sources and credit

• QLP target list: https://archive.stsci.edu/hlsps/qlp/target_lists/s0098.csv
• QLP light curves (MAST High Level Science Product): https://archive.stsci.edu/hlsp/qlp
• Cite the QLP data as the MAST HLSP page asks: DOI 10.17909/t9-r086-e880 (https://doi.org/10.17909/t9-r086-e880); the page lists the QLP papers (Huang et al. 2020a, 2020b; Kunimoto et al. 2021, 2022).

License

The source light curves are public data from NASA's Mikulski Archive for Space Telescopes (MAST). This derived prototype adds no restriction of its own; follow the citation request on the MAST page above.