Researchers have detected a mysterious signal with the Mercator Telescope on La palma.
This unexpected signal indicates that the star Delta Cephei has a hidden companion. And this is pretty much a problem since this star is actually used to determine distances in the nearby universe.
Delta Cephei is one of the most studied star. It is known since more than 100 years and used to calibrate the cosmic distance scale. So it is really disturbing to find a hidden companion!
The strange space signal has been detected during precise and long-term measurements with the Hermes spectrograph on the Mercator telescope on the Canary island of La Palma.
Why is Delta Cephei so important?
Delta Cephei is a so-called “variable star”. The brightness of these stars varies in a short period of time – 5.4 days for Delta Cephei. For over 100 years, astronomers use this characteristic to calibrate the cosmic distance scale. Delta Cephei is even a prototype for a class of similar stars dubbed Cepheids.
This is an amazing space discovery which may influence existing cosmic distance models.