Classification of nearby cool white dwarfs and subdwarfs

• Applicant: Dr. Ralf-Dieter Scholz
• Subject Area: Astrophysics and Astronomy
• Term: Funded in 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 106925800

Surprisingly, about one third of the stellar systems within 10 pc and two thirds within 25 pchave not yet been identified. In recent years, many efforts have improved the situation andled e.g. to an increase of 20% in the number of M dwarfs in the 10 pc sample. Few whitedwarfs (WDs) have been discovered beyond the 1Ü pc horizon. There is a remarkable selectioneffect in the 10 pc sample: 17 of 18 known WDs have proper motions fj. > I arcsec/yr,but only 50% of all stars show such large proper motions. We propose to obtain classificationspectroscopy for a complete northern sky sample of ~400 colour and proper motion selectedWD candidates lacking spectral type information. Among them we expect to find 1) missingnearby WDs, 2) more distant high-velocity subdwarfs.

• DFG Programme: Research Grants