Discovery of An Unusually Blue L Dwarf Within 10 pc of the Sun

TL;DR

This paper reports the discovery of an unusually blue L5 dwarf within 10 parsecs of the Sun, which was overlooked in previous infrared surveys due to its color, and discusses its implications for the local L dwarf population.

Contribution

The discovery of a nearby blue L dwarf that was missed by infrared color searches, highlighting potential incompleteness in the L dwarf luminosity function.

Findings

SDSS J141624.08+134826.7 is within 10 pc of the Sun.

It is the nearest blue L dwarf and increases known L5 dwarfs by 20%.

Its properties suggest the L dwarf luminosity function may be incomplete.

Abstract

We report the discovery of an unusually blue L5 dwarf within 10 pc of the Sun from a search of Sloan Digital Sky Survey (SDSS) spectra. A spectrophotometric distance estimate of 8.0+/-1.6 pc places SDSS J141624.08+134826.7 among the six closest known L dwarfs. SDSS 1416+13 was overlooked in infrared color-based searches because of its unusually blue J-K_S color, which also identifies it as the nearest member of the blue L dwarf subclass. We present additional infrared and optical spectroscopy from the IRTF/SpeX and Magellan/MagE spectrographs and determine UVW motions that indicate thin disk kinematics. The inclusion of SDSS 1416+13 in the 20 pc sample of L dwarfs increases the number of L5 dwarfs by 20% suggesting that the L dwarf luminosity function may be far from complete.