
science & techESA/Hubble1826
NGC 6861 is a lenticular galaxy, a halfway type between spirals and ellipticals
NGC 6861 was discovered in 1826 by the Scottish astronomer James Dunlop, and it is now known to be the second brightest member of the Telescopium Group, a cluster of at least a dozen galaxies. Its dark dust lanes show that it is seen partly tilted, and they are typical of spirals. Its smooth white oval of stars looks like an elliptical galaxy. It is a lenticular galaxy, a class that has features of both. Astronomers do not yet fully understand how the three types are related. A lenticular galaxy could be a spiral that ran out of gas and lost its arms, or the result of two galaxies merging, and a galaxy in a crowded group is more likely to merge.
Lenticular galaxies show that galaxies do not fall neatly into spiral and elliptical boxes. Working out whether they are faded spirals or merger remnants is a key question for understanding how galaxies change over time.
Lenticular galaxies are named for their lens-like shape.
