The First Ultra-Cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer

TL;DR

This paper reports the discovery of the first ultra-cool brown dwarf by WISE, demonstrating WISE's capability to find the coolest, nearest substellar objects suitable for detailed follow-up observations.

Contribution

It presents the discovery and characterization of a new ultra-cool brown dwarf, the first identified by WISE, highlighting WISE's effectiveness in finding nearby, cool substellar objects.

Findings

Discovered a T9 brown dwarf at 6-10 pc distance.

Spectroscopic analysis indicates an effective temperature of ~600 K.

Demonstrates WISE's capability to find the coolest, nearest brown dwarfs.

Abstract

We report the discovery of the first new ultra-cool brown dwarf found with the Wide-field Infrared Survey Explorer (WISE). The object's preliminary designation is WISEPC J045853.90+643451.9. Follow-up spectroscopy with the LUCIFER instrument on the Large Binocular Telescope indicates that it is a very late-type T dwarf with a spectral type approximately equal to T9. Fits to an IRTF/SpeX 0.8-2.5 micron spectrum to the model atmospheres of Marley and Saumon indicate an effective temperature of approximately 600 K as well as the presence of vertical mixing in its atmosphere. The new brown dwarf is easily detected by WISE, with a signal-to-noise ratio of ~36 at 4.6 microns. Current estimates place it at a distance of 6 to 10 pc. This object represents the first in what will likely be hundreds of nearby brown dwarfs found by WISE that will be suitable for follow up observations, including those with the James Webb Space Telescope. One of the two primary scientific goals of the WISE mission is to find the coolest, closest stars to our Sun; the discovery of this new brown dwarf proves that WISE is capable of fulfilling this objective.