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 Y |
| Astrometry | |
| Parallax (π) | 454 ± 45 mas |
| Distance | 7.175 ly (2.2 pc) |
| Details | |
| Mass | 3-10 MJup |
| Temperature | 225-260 K |
WISE 0855–0714 (full designation WISE J085510.83–071442.5[2]) is a (sub-)brown dwarf 7.175+0.783
−0.652 light-years (2.2+0.24
−0.2 parsecs) from Earth announced in 2014 by Kevin Luhman using data from the Wide-field Infrared Survey Explorer (WISE).[1] As of April 2014[update] it has the third-highest proper motion (8.1±0.1″ yr–1) and the fourth-largest parallax (454±45 mas) 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 between 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.
Based on direct observations the object has a large parallax which specifically relates to its distance from the solar system. This phenomena results in a distance of around 7.2±0.7 light years, with a small margin of error due to the strength of the parallax effect and the clarity of the observations. The object's proper motion across the sky is also directly observed over time which helped lead to its discovery as it "stood out" in the observations, but the proper motion is itself a combination of the speed of the object 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.
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.[2]
Model derived understanding
Based on models of brown dwarfs WISE 0855–0714's is estimated to have a mass of 3 to 10 MJ.[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 MJ, capable of fusing deuterium, to be a brown dwarf. A lighter object and orbiting another object is considered a planet.[3] 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.[4]
Combining its luminosity, distance, and mass it is estimated to be the coldest known brown dwarf so far detected, 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 MJ.
- 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 25 April 2014.
{{cite web}}:|archive-date=/|archive-url=timestamp mismatch; 26 April 2014 suggested (help); Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ a b Luhman, K. 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. doi:10.1088/2041-8205/786/2/L18.
- ^ "Working Group on Extrasolar Planets: Definition of a "Planet"". IAU position statement. 2003-02-28. Retrieved 2014-04-28.
- ^ Leonidas Papadopoulos (April 28, 2014). "Between the Planet and the Star: A New Ultra-Cold, Sub-Stellar Object Discovered Close to Sun". AmericaSpace.com. Retrieved April 28, 2014.
Further reading
- Beichman, C.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Cushing, Michael C.; Dodson-Robinson, Sally; Marley, Mark S.; Morley, Caroline V.; Wright, E. L. (2014). "WISE Y Dwarfs As Probes of the Brown Dwarf-Exoplanet Connection". The Astrophysical Journal. 783 (2): 68. arXiv:1401.1194v2. doi:10.1088/0004-637X/783/2/68.