Source-linked AI summary
The first WASP public data release
O. W. Butters, R. G. West, D. R. Anderson, A. Collier Cameron, W. I. Clarkson, B. Enoch, C. A. Haswell, C. Hellier, K. Horne, Y. Joshi, S. R. Kane, T. A. Lister, P. F. L. Maxted, N. Parley, D. Pollacco, B. Smalley, R. A. Street, I. Todd, P. J. Wheatley, D. M. Wilson
TL;DR
WASP’s wide-field survey gathers light curves to search for transiting exoplanets, while the data also suit other time-domain studies. DR1 releases millions of images and light curves, with more than 119 billion data points across the catalogued objects.
Problem
WASP’s survey produces light curves for transit searches, and their format also suits variable-star and single-star studies.
Source: §1 · p. 1Method
DR1 makes the WASP archive’s processed light curves and raw images available for download through the web interface or virtual observatory.
Source: §4.1 · p. 2, §6 · p. 4Results
3,631,972 raw science images and 17,970,937 unique objects with 119,930,299,362 data points are included in the release.
Source: §3 · p. 2Takeaways & Limitations
The light-curve dataset can serve the wider time-domain astronomy community, including variable-star and single-star studies.
Source: §1 · p. 1Because this release includes only sources matched to USNO-B1.0, transient sources are unlikely to be present.
Source: §2 · p. 2
Abstract
from arXiv · showhide
The WASP (Wide Angle Search for Planets) project is an exoplanet transit survey that has been automatically taking wide field images since 2004. Two instruments, one in La Palma and the other in South Africa, continually monitor the night sky, building up light curves of millions of unique objects. These light curves are used to search for the characteristics of exoplanetary transits. This first public data release (DR1) of the WASP archive makes available all the light curve data and images from 2004 up to 2008 in both the Northern and Southern hemispheres. A web interface (www.wasp.le.ac.uk/public/) to the data allows easy access over the Internet. The data set contains 3 631 972 raw images and 17 970 937 light curves. In total the light curves have 119 930 299 362 data points available between them.
1. Introduction
WASP’s northern and southern robotic survey has built extensive light curves used to search for transiting planets, and DR1 makes a substantial part of the archive public.
- The project’s two robotic observatories have found almost half of the known transiting systems described in the introduction.Source: §1 · p. 1
- Since 2004, WASP has collected well over 200 billion data points, and its light curves have yielded over 30 transiting planets.Source: §1 · p. 1
- The light-curve format also supports variable-star and single-star studies, making the dataset a resource for time-domain astronomers.Source: §1 · p. 1
- DR1 represents over half of WASP’s current data holdings, with later releases planned to cover more sky and a longer temporal baseline.Source: §1 · p. 1
2. The WASP observatories
WASP uses twin robotic observatories to collect wide-field photometry, which is processed into an archive for high-level analysis and transit searches.
- Each observatory has eight 200 mm lenses and a 2048×2048 CCD per camera; since 2006, the system has used a 400–700 nm broadband filter.The filter passband is plotted with atmospheric, CCD, and lens transmission in Fig. 1.Source: §2 · p. 1, Figure 1 · p. 2
- The telescopes cycle through 6–8 fields, taking two 30-second exposures per field and sampling each field every 9–12 minutes.The strategy is adjusted to avoid crowded fields near the Galactic plane.Source: §2 · p. 2
- Queen’s and Keele process the raw images into photometric measurements, which are archived at Leicester for de-trending and searches for exoplanet signatures.Source: §2 · p. 2
- Only sources matched to the USNO-B1.0 catalogue are included in this release, so transient sources are unlikely to appear.Source: §2 · p. 2
3. Data summary
DR1 provides millions of science images and light curves, with coverage spanning different sky regions and date ranges in the two hemispheres.
- 3,631,972 raw science images and 17,970,937 unique objects with 119,930,299,362 data points are included in the release.Source: §3 · p. 2
- Table 1 summarizes the release’s spatial and temporal coverage: North data run from May 2004 to August 2008, while South data run from February 2006 to May 2008.Source: Table 1 · p. 2, §3 · p. 2
- Fig. 2 presents a Hammer-Aitoff projection of the average number of data points per light curve across the release.Source: Figure 2 · p. 2
4. Data products
WASP DR1 provides individual-object light curves alongside raw science and calibration images. The data products include photometric corrections and metadata, with version records for tracking software changes.
4.1. Light curves
- Light curves are stored as binary FITS tables, with some spanning back to 2004 and an average of about 6,600 data points per curve.Some curves contain more than 70,000 points.Source: §4.1 · p. 2
- Each light-curve point contains processed flux, and a TAMUZ-corrected flux provides more consistent measurements across cameras and years.The tables also include object CCD position, image ID, and a correction flag.Source: §4.1 · pp. 2–3
4.2.1. Science frames
- Some 2004 science-image headers lack WCS metadata, and images with localized quality problems such as satellite trails remain in the archive.The authors retain these images because the defects do not affect the whole image.Source: §4.2.1 · p. 3
4.2.2. Calibration frames
- Calibration frames are generally taken at dusk and dawn, but may be absent on nights when weather prevents those observations.They use the science-frame naming convention and are distinguished by the IMGTYPE header keyword.Source: §4.2.2 · p. 3
4.3. Version control
- FITS headers record which software edited a file and when, while web-page version logs allow users to check whether upgrades affected data products.Source: §4.3 · p. 3
5. The interface
The web interface supports sky-region searches and downloads of light curves and images, while the virtual-observatory index enables catalogue cross-matching and standard-tool analysis.
5. The interface
- Users can search for objects by sky position, magnitude range, and minimum data-point count, then download individual or multiple light curves.Individual light curves also have unique URLs, and adding Table 2 metadata on the fly significantly slows retrieval.Source: §5.1 · p. 3
5.2. Science and calibration images
- Science images can be searched by sky region using a 5.52-degree radius or retrieved by light-curve object ID to find its contributing images.Calibration-image availability is summarized for nightly or monthly downloads per camera.Source: §5.2 · pp. 3–4
5.3. Virtual observatory
- The light-curve index in the virtual observatory supports cross-correlation with other catalogues and retrieval for analysis with standard virtual-observatory tools.Source: §5.3 · p. 4
6. Conclusion
WASP DR1 makes more than 3.5 million images and almost 18 million light curves covering a large fraction of the sky available for download. The archive is expected to grow in sky coverage and temporal baseline.
6. Conclusion
- DR1 contains over 3.5 million images and almost 18 million light curves covering a large fraction of the sky.Source: §6 · p. 4
- The archive is available for download through the web interface or virtual observatory.Source: §6 · p. 4
- Future additions are expected to expand the archive's sky coverage and temporal baseline.Source: §6 · p. 4