APOD: 2026 September 9 – Witness XZ Andromedae Wink
The post APOD: 2026 September 9 – Witness XZ Andromedae Wink appeared first on NASA Science .
Today's Astronomy Picture of the Day (APOD) features an animation of the star system XZ Andromedae. This system comprises two stars, with the central object highlighted by bold lines. XZ Andromedae is an Algol-type eclipsing binary, meaning its nearly edge-on orbit allows us to observe it from Earth. As the cooler star passes in front of its hotter, brighter companion, the light from the system dims and brightens, which is evident in the bottom light curve of the animation.
Analysis of multiple light curves of XZ Andromedae suggests the possibility of two additional stars orbiting this system. The animations were created using Citizen Astronomy, an open-source software that aids in differential photometry. This technique helps minimize variations caused by the instrument and Earth's atmosphere by comparing the brightness of the target star with a comparison star.
Apart from eclipsing binaries, this analysis is beneficial for studying various astronomical phenomena, including transiting exoplanets, accreting black holes, supernovae, and more. Astrophotographers are encouraged to experiment with this software on their own data.
The main NASA website for APOD has recently shifted from apod.nasa.gov to science.nasa.gov/apod. The animation showcasing XZ Andromedae is set to be featured on the APOD website tomorrow, with the potential image being a giraffe.
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