Thegalaxy is a satellite of theMilky Way and contains sixglobular clusters, an unusually high number for its size;[5] the largest,NGC 1049, was discovered before the galaxy itself. The galaxy is also receding from theMilky Way at 53 km/s. It mostly containspopulation II stars, but also has populations of young and intermediate age.[2]
Using theHubble Space Telescope, scientists derived acolor-magnitude diagram forFornax 4, a globular cluster within this galaxy. Unlike theglobular clusters Fornax 1, 2, 3, and 5, which havehorizontal branches across a wide range of colors and includeRR Lyrae variables, Fornax 4 is found to have only red in its horizontal branch. Fornax 4 is also ~3 Gyr younger than the other globular clusters. The color-magnitude diagram of Fornax 4 has a strong similarity to "young" galactic globularRuprecht 106.[6]
It has been debated for some time whether the globular cluster Fornax 6 is a true member of the Fornax Dwarf, or merely a chance alignment of stars and/or galaxies.[5] A 2021 study found it to be a true cluster and a member, but it is notably moremetal-rich and therefore likely younger than the other clusters. It is estimated to be about 2 billion years old.[5]
It is not known why spheroidals allow the formation of globular clusters like Fornax 4 andTerzan 7 (ofSagittarius dwarf) long after globular clusters ceased to form in the main body of the Galactic halo. Another possibility is that "young" globular clusters of the outer halo like Ruprecht 106 were originally formed in now defunct dwarf spheroidals.[7]
Media related toFornax dwarf at Wikimedia Commons
