WD 1145 017

Stellar characteristics

The white dwarf has a mass of 0.6 M_☉, radius of 0.02 R_☉ (1.4 R_⊕) and a temperature of 15,900 K, typical for white dwarf stars. It has been a white dwarf for 175 million years. The star included strong absorption lines due to magnesium, aluminium, silicon, calcium iron and nickel. These elements commonly found in rocky planets are polluting the surface of the star, and would normally be expected to mix through the star and disappear from view after a million years.

Based on recent studies and its mass, the star was likely an early F-type main sequence star (spectral type F0) before it became a red giant.

The apparent magnitude of the star, or how bright it appears from Earth's perspective, is about 17. Therefore, it is too dim to be seen with the naked eye.

Planetary system

The supposed planetesimal, WD 1145+017 b, with a 4.5 hour orbit, is being ripped apart by the star and a remnant of the former planetary system that the star hosted before becoming a white dwarf. It is the first observation of a planetological object being shredded by a white dwarf. Several other large pieces have been seen in orbit as well. All the various larger pieces have orbits of 4.5 to 4.9 hours. Rocky material is raining down onto the star, and showing up in the star's spectrum. The system was detected by the Kepler space telescope in its extended K2 mission. Though the system was not a target of interest, it was within the field of view of observing sessions, and analysis of the observed data revealed the system.

An excess of infrared radiation indicates that there is a dusty disk with a temperature of 1,150 K (880 °C).