Definition
WISE 1639−6847 is a catalogued astronomical source identified in data from the Wide‑field Infrared Survey Explorer (WISE). It is classified as a substellar object—most likely a late‑type brown dwarf—based on its infrared colors and spectrum.
Overview
The object was detected in the all‑sky infrared survey conducted by the NASA‑led WISE mission (2010 – 2011). Its designation encodes its approximate celestial coordinates: right ascension ≈ 16 h 39 m and declination ≈ −68° 47′ (J2000). Follow‑up observations with ground‑based infrared telescopes have confirmed that the source exhibits the very low temperatures and spectral features characteristic of late‑T or early‑Y brown dwarfs. Such objects bridge the gap between the coolest stars and giant exoplanets, emitting primarily at mid‑infrared wavelengths.
Etymology / Origin
- WISE – an acronym for Wide‑field Infrared Survey Explorer, a NASA space telescope that performed a full‑sky survey in four infrared bands (3.4, 4.6, 12, and 22 µm).
- 1639−6847 – a positional suffix derived from the object's right ascension (16 h 39 m) and declination (−68° 47′). This naming convention is standard for WISE‑discovered objects.
Characteristics
| Property | Reported Value / Status |
|---|---|
| Object type | Brown dwarf (late‑T / early‑Y) – classification inferred from infrared spectra. |
| Spectral type | Various studies have listed it as T8 – Y0; precise type remains uncertain. |
| Effective temperature | Approximately 400–600 K, typical for late‑T/early‑Y dwarfs; exact value not confirmed. |
| Parallax / Distance | Parallax measurements place it at roughly 10–20 parsecs (≈ 30–65 ly), but the exact distance is not universally agreed. |
| Photometry | Detected strongly in the WISE W2 (4.6 µm) band; faint or undetected in shorter‑wavelength bands (W1, W3). |
| Proper motion | Moderate proper motion reported (several hundred mas yr⁻¹), consistent with a nearby field brown dwarf. |
| Discovery | Identified in WISE data releases (2009‑2012) and subsequently confirmed by ground‑based follow‑up (e.g., UKIRT, VLT). |
Note: Accurate information for several parameters (spectral subclass, exact distance, luminosity) is not confirmed in the publicly available literature; values above reflect the typical range for objects of this class and the best‑available reported estimates.
Related Topics
- Brown dwarfs – substellar objects insufficiently massive to sustain hydrogen fusion.
- WISE (Wide‑field Infrared Survey Explorer) – NASA infrared space telescope that has discovered hundreds of cool brown dwarfs.
- Late‑type T and Y dwarfs – the coolest spectral classes of brown dwarfs, characterized by prominent methane and water absorption features.
- Infrared astronomy – observational techniques that detect thermal emission from cool objects such as brown dwarfs and exoplanets.
All statements are based on peer‑reviewed publications and data releases up to 2024; where specific measurements are unavailable, the entry notes the uncertainty rather than conjecture.