Epoch MJD 55467.61 Equinox J2000
|Right ascension||18h 28m 31.10s|
|Declination||26° 50′ 37.79″|
|Apparent magnitude (J (MKO filter system))||23.57 ± 0.35|
|Apparent magnitude (H (MKO filter system))||22.45 ± 0.08|
|Proper motion (μ)||RA: 954 ± 11 mas/yr
Dec.: 153 ± 12.5 mas/yr
|Parallax (π)||90 ± 9.5 mas|
|Distance||approx. 36 ly
(approx. 11 pc)
|Mass||~ 3—6 (0.5—20) MJup|
|Age||~ 2—4 (0.1—10) Gyr|
WISEPA J182831.08+265037.8 (designation is abbreviated to WISE 1828+2650) is a brown dwarf or free-floating planet of spectral class >Y2, located in constellation Lyra at approximately 37 light-years from Earth. It is the "archetypal member" of the Y spectral class.
WISE 1828+2650 was discovered in 2011 from data, collected by Wide-field Infrared Survey Explorer (WISE) Earth-orbiting satellite — NASA infrared-wavelength 40 cm (16 in) space telescope, which mission lasted from December 2009 to February 2011. WISE 1828+2650 has two discovery papers: Kirkpatrick et al. (2011) and Cushing et al. (2011), however, basically with the same authors and published nearly simultaneously. Kirkpatrick et al. presented discovery of 98 new found by WISE brown dwarf systems with components of spectral types M, L, T and Y, among which also was WISE 1828+2650 — coolest of them.[note 1] Cushing et al. presented discovery of seven brown dwarfs — one of T9.5 type, and six of Y-type — first members of the Y spectral class, ever discovered and spectroscopically confirmed, including "archetypal member" of the Y spectral class — WISE 1828+2650. This seven objects are also the faintest seven of 98 brown dwarfs, presented in Kirkpatrick et al. (2011).
WISE 1828+2650 distance estimates
|Source||Parallax, mas||Distance, pc||Distance, ly||Ref.|
|Kirkpatrick et al. (2011)
|Beichman et al. (2013)
(according Kirkpatrick et al. (2012))
|122 ± 13||8.2+1.0
|Beichman et al. (2013)||90 ± 9.5||11.2+1.3
Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.
Proper motion 
WISE 1828+2650 has proper motion of about 966 milliarcseconds per year.
WISE 1828+2650 proper motion estimates
|Kirkpatrick et al. (2011)||1084||84||1078 ± 327||118 ± 409|||
|Beichman et al. (2013)||966||81||954 ± 11||153 ± 12.5|||
The most accurate estimates are marked in bold.
Physical properties 
WISE 1828+2650 may be the coolest currently known brown dwarf or the first example of free-floating planet (it is not currently known if it a brown dwarf or a free-floating planet). It has a temperature in the range 250—400 K (-23—127 °C / -10—260 °F) (initially was estimated below 300 K (about 27 °C / 80 °F)). It has been assigned the latest known spectral class (>Y2, initially estimated as >Y0).
WISE 1828+2650 is similar in appearance to the other Y-type object WD 0806-661 B. WD 0806-661 B could have formed as a planet close to its primary, WD 0806-661 A, and later, when the primary became a white dwarf and lost most of its mass, have migrated into a larger orbit of 2500 AU, and similarity between WD 0806-661 B and WISE 1828+2650 may indicate that WISE 1828+2650 had formed in the same way.
Comparison between WISE 1828+2650 and WD 0806-661 B may suggest that WISE 1828+2650 is a system of two equal-mass objects. Observations with Hubble Space Telescope (HST) and Keck-II LGS-AO system had not revealed binarity, suggesting that if any such companion exists, it would have an orbit less than 0.5 AU, and no evidence for binarity yet exists.
See also 
The other six discoveries of brown dwarfs, published by Cushing et al. in 2011:
- WISE 0148-7202 (T9.5)
- WISE 0410+1502 (Y0)
- WISE 1405+5534 (Y0 (pec?))
- WISE 1541-2250 (Y0.5)
- WISE 1738+2732 (Y0)
- WISE 2056+1459 (Y0)
- These 98 brown dwarf systems are only among first, not all brown dwarf systems, discovered from data, collected by WISE: six discoveries were published earlier (however, also listed in Kirkpatrick et al. (2011)) in Mainzer et al. (2011) and Burgasser et al. (2011), and the other discoveries were published later.
- This may indicate that WISE 1828+2650 is more likely a free-floating planet, not a brown dwarf, since it is below the lower mass limit for brown dwarfs (~13 MJup, see brown dwarf).
- Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Mainzer, A.; Eisenhardt, Peter R.; McLean, Ian S.; Thompson, Maggie A.; Bauer, James M.; Benford, Dominic J.; Bridge, Carrie R.; Lake, Sean E.; Petty, Sara M.; Stanford, S. A.; Tsai, Chao-Wei; Bailey, Vanessa; Beichman, Charles A.; Bloom, Joshua S.; Bochanski, John J.; Burgasser, Adam J.; Capak, Peter L.; Cruz, Kelle L.; Hinz, Philip M.; Kartaltepe, Jeyhan S.; Knox, Russell P.; Manohar, Swarnima; Masters, Daniel; Morales-Calderon, Maria; Prato, Lisa A.; Rodigas, Timothy J.; Salvato, Mara; Schurr, Steven D.; Scoville, Nicholas Z.; Simcoe, Robert A.; Stapelfeldt, Karl R.; Stern, Daniel; Stock, Nathan D.; Vacca, William D. (2011). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal Supplement 197 (2): 19. arXiv:1108.4677v1. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19.
- Beichman, Charles A.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Barman, Travis S.; Marsh, Kenneth A.; Cushing, Michael C.; Wright, E. L. (2013). "The Coldest Brown Dwarf (Or Free Floating Planet)?: The Y Dwarf WISE 1828+2650". arXiv:1301.1669v1 [astro-ph.SR]. Bibcode 2013arXiv1301.1669B.
- Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Mainzer, A.; Marsh, Kenneth A.; Beichman, Charles A.; Burgasser, Adam J.; Prato, Lisa A.; Simcoe, Robert A.; Marley, Mark S.; Saumon, D.; Freedman, Richard S.; Eisenhardt, Peter R.; Wright, Edward L. (2011). "The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)". arXiv:1108.4678v1 [astro-ph.SR]. Bibcode 2011ApJ...743...50C. doi:10.1088/0004-637X/743/1/50.
- Kirkpatrick, J. Davy; Gelino, Christopher R.; Cushing, Michael C.; Mace, Gregory N.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Eisenhardt, Peter R.; McLean, Ian S.; Mainzer, Amanda K.; Burgasser, Adam J.; Tinney, C. G.; Parker, Stephen; Salter, Graeme (2012). "Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function". The Astrophysical Journal 753 (2): 156. arXiv:1205.2122. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156.
- Choi, Charles Q. (August 26, 2011). "Y dwarf star? Because they're cool, that's Y!". Space.com. Retrieved August 31, 2011.
- NASA news release
- Science news
- Infrared image of WISE 1828+2650 at Astronomy Picture of the Day, 2011 August 30
- Solstation.com (New Objects within 20 light-years)
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