Three active M dwarfs within 8 pc: L 449-1, L 43-72, and LP 949-15

¹ Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany e-mail: [rdscholz;vhambaryan;aschwope]@aip.de
² European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago 19, Chile e-mail: glocurto@eso.org
³ Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile e-mail: [rmendez;costa]@das.uchile.cl
⁴ Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302-4106, USA e-mail: thenry@chara.gsu.edu

Received: 29 March 2005
Accepted: 11 May 2005

Abstract

Three nearby star candidates were selected as bright 2MASS point sources without associated optical sources, i.e. with potentially large proper motions, subsequently confirmed by multi-epoch optical data from the SuperCOSMOS Sky Surveys. All three objects are listed in the NLTT catalogue of high proper motion stars. Follow-up spectroscopic observations allowed us to classify L 449-1 as M 4.0e dwarf at 5.7 pc, L 43-72 as M 4.5e dwarf at 7.2 pc, and LP 949-15 as M 5.0e dwarf at 6.1 pc, using known absolute JHK_s magnitudes of dwarfs with corresponding spectral types, respectively. All three stars exhibit Hα emission lines, and all three can be identified with bright X-ray sources. The available ROSAT light curves of two of the objects show typical flare-like variability. Thus, all three stars are active, very close potential neighbours of the Sun, previously not mentioned as such, certainly deserving further attention. In particular, these are very promising candidates for trigonometric parallax programs.