WISE 0855−0714
.gif) Time-lapsed photo sequence of WISE 0855−0714's movement in the sky using captured images from the WISE and the Spitzer telescopes.[1] | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 55m 10.83s |
| Declination | −07° 14′ 42.5″ |
| Characteristics | |
| Evolutionary stage | Sub-brown dwarf |
| Spectral type | Class Y2 |
| Apparent magnitude (J) | 25.00±0.53[2] |
| Astrometry | |
| Proper motion (μ) | RA: −8118±8[3] mas/yr Dec.: 680±7[3] mas/yr |
| Parallax (π) | 449 ± 8 mas[3] |
| Distance | 7.27±0.13 ly (2.23±0.04 pc) |
| Details | |
| Mass | ~3–10 MJup |
| Temperature | 225-260 K |
| Other designations | |
WISEA J085510.74-071442.5 | |
| Database references | |
| SIMBAD | data |
WISE 0855−0714 (full designation WISE J085510.83−071442.5[4]) is a sub-brown dwarf 2.23±0.04 parsecs (7.27±0.13 light-years)[3] from Earth, the discovery of which was announced in April 2014 by Kevin Luhman using data from the Wide-field Infrared Survey Explorer (WISE).[1] As of 2014[update], WISE 0855−0714 has the third-highest proper motion (8118±8 mas/yr)[3] after Barnard's Star (10300 mas/yr) and Kapteyn's Star (8600 mas/yr)[4] and the fourth-largest parallax (449±8 mas)[3] of any known star or brown dwarf, meaning it is the fourth-closest extrasolar system to the Sun.[1] It is also the coldest object of its type found in interstellar space, having a temperature in the range 225 to 260 K (−48 to −13 °C; −55 to 8 °F).[1]
Characterization
Observations
The WISE object was detected in March 2013, and follow-up observations were taken by the Spitzer Space Telescope and the Gemini North telescope.[1] The name WISE J085510.83−071442.5 includes the coordinates and indicates that the object is located in the constellation Hydra.
Distance and proper motion
Based on direct observations, WISE 0855−0714 has a large parallax, which specifically relates to its distance from the Solar System. This phenomenon results in a distance of around 7.27±0.13 light-years,[3] with a small margin of error due to the strength of the parallax effect and the clarity of observations. WISE 0855−0714's proper motion across the sky is also directly observed over time, causing it to stand out in the observations, but the proper motion is itself a combination of its speed in the galactic neighborhood relative to the Solar System as well as its proximity to the Solar System. If it were moving exactly as fast but farther away, if it were moving more slowly but closer, or if it were moving more quickly near to the Sun but moving at a high angle towards or away from the Sun, it would have a smaller proper motion.
Spectrometry
Its luminosity in different bands of the thermal infrared in combination with its absolute magnitude—because of its known distance—was used to place it in context of different models; the best characterization of its brightness was in the W2 band of 4.6 μm at an apparent magnitude of 13.89±0.05, though it was brighter into the deeper infrared.[4] Infrared images taken with the Magellan Baade Telescope suggest evidence of water clouds.[5]
Model-derived understanding
Based on models of brown dwarfs WISE 0855−0714's is estimated to have a mass of 3 to 10 MJup.[1] This mass is in the range of a sub-brown dwarf or other planetary-mass object.
As of 2003, the International Astronomical Union considers an object with a mass above 13 MJup, capable of fusing deuterium, to be a brown dwarf. A lighter object and one orbiting another object is considered a planet.[6] So far this WISE object is alone, though it could be a rogue planet, something first identified in 2004 in the case of Cha 110913-773444.[7]
Combining its luminosity, distance, and mass it is estimated to be the coldest-known brown dwarf, with a modeled effective temperature of 225 to 260 K (−48 to −13 °C; −55 to 8 °F), depending on the model.[1]
See also
- CFBDSIR 2149-0403, the first free-floating object with a confirmed mass below 13 MJup.
- List of nearest stars and brown dwarfs
- Luhman 16
- PSO J318.5-22
References
- ^ a b c d e f g h Clavin, Whitney; Harrington, J. D. (25 April 2014). "NASA's Spitzer and WISE Telescopes Find Close, Cold Neighbor of Sun". NASA.gov. Archived from the original on 26 April 2014.
- ^ "WISEA J085510.74-071442.5". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 15 May 2017.
- ^ a b c d e f g Luhman, Kevin L.; Esplin, Taran L. (September 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (2). 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b c Luhman, Kevin L. (21 April 2014). "Discovery of a ~250 K Brown Dwarf at 2 pc from the Sun". The Astrophysical Journal Letters. 786 (2): L18. arXiv:1404.6501. Bibcode:2014ApJ...786L..18L. doi:10.1088/2041-8205/786/2/L18.
- ^ Faherty, Jacqueline K.; Tinney, C. G.; Skemer, Andrew; Monson, Andrew J. (August 2014). "Indications of Water Clouds in the Coldest Known Brown Dwarf". Astrophysical Journal Letters. arXiv:1408.4671. Bibcode:2014ApJ...793L..16F. doi:10.1088/2041-8205/793/1/L16.
- ^ "Working Group on Extrasolar Planets: Definition of a "Planet"". Working Group on Extrasolar Planets of the International Astronomical Union. 28 February 2003. Retrieved 28 April 2014.
- ^ Papadopoulos, Leonidas (28 April 2014). "Between the Planet and the Star: A New Ultra-Cold, Sub-Stellar Object Discovered Close to Sun". AmericaSpace.com. Retrieved 28 April 2014.
Further reading
- Beichman, C.; Gelino, Christopher R.; et al. (2014). "WISE Y Dwarfs As Probes of the Brown Dwarf-Exoplanet Connection". The Astrophysical Journal. 783 (2): 68. arXiv:1401.1194. Bibcode:2014ApJ...783...68B. doi:10.1088/0004-637X/783/2/68. (Note: WISE 0855−0714 is not mentioned in this paper; it is about other Y-type objects discovered by WISE.)
- Luhman, Kevin L.; Esplin, Taran L. (2014). "A New Parallax Measurement for the Coldest Known Brown Dwarf". The Astrophysical Journal. 796 (1): 6. arXiv:1409.5899. Bibcode:2014ApJ...796....6L. doi:10.1088/0004-637X/796/1/6.
- Wright, Edward L.; Mainzer, Amy; et al. (2014). "NEOWISE-R Observation of the Coolest Known Brown Dwarf". The Astronomical Journal. 148 (5): 82. arXiv:1405.7350. Bibcode:2014AJ....148...82W. doi:10.1088/0004-6256/148/5/82.
External links
- WISE J0855-0714 at Solstation.com