SDSS J141624.08+134826.7 (abbreviated SDSS J1416+1348) is a nearby wide binary system of two brown dwarfs, located in constellation Boötes. The system consists of L-type component A and T-type component B.
Component B was discovered in early 2010 from UKIDSS Large Area Survey (ULAS) Data Release 5[5] & 6,[4] an astronomical survey conducted on the United Kingdom Infrared Telescope (UKIRT) on Mauna Kea in Hawaii. It has also two discovery papers: Burningham et al., 2010[5] and Scholz, 2010.[4] Burningham et al. discovered the whole system (independently of Bowler et al. and Schmidt et al.[5]) by cross-matching the ULAS DR5 against SDSS DR7,[5] and Scholz discovered component B by inspecting the UKIDSS finding charts around already found component A.[4]
Distance
In 2012 was published the first relatively precise parallax of SDSS J1416+1348, measured at the Canada-France-Hawaii Telescope under The Hawaii Infrared Parallax Program: 109.9 ± 1.8 mas, corresponding to a distance 9.10 ± 0.15 pc (29.7 ± 0.5 ly).[7] (Although, two parallaxes with large errors was previously published by Bowler et al.[3] and Scholz[4]).
Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.
Space motion
SDSS J1416+1348 has proper motion 165 mas·yr−1 with position angle 32 degrees, indicating motion in north-east direction on the sky. Corresponding right ascension and declination components of proper motion are 88.0 ± 2.8 mas/yr and 139.9 ± 1.3 mas/yr, respectively.[6] At distance 29.7 ly (assuming parallax 109.0 ± 1.8 mas),[7] corresponding tangential velocity is 7.1 km/s. Radial velocity of SDSS J1416+1348 is -42.2 ± 5.1 km/s.[6] (Negative radial velocity value indicates that SDSS J1416+1348 is now approaching to us). Total velocity of SDSS J1416+1348 relatively to Solar system is 42.8 km/s.
Since SDSS J1416+1348 moves much faster in radial direction than in tangential direction, and radial velocity is negative, this brown dwarf system should pass the Solar System in the future at a much smaller distance than today's distance. Proper motion and radial velocity values from Schmidt et al., 2009 and parallax from Dupuy & Liu, 2012, assuming motion with constant velocity along straight line, yield minimal distance 4.9 ly circa year 207100.
Solar encounter chronology, assuming motion with constant velocity in a straight line relative to the Solar System:[note 5]
SDSS J1416+1348 is an old system (age estimates: >0.8 Gyr,[6] ~10 Gyr,[5] ~5 Gyr,[4] 2–10 Gyr,[13] >3.2 Gyr[9]), and, probably, possesses low metallicity.[5] Its two components are separated at angular distance 9.81 arcsec, corresponding to a projected separation 89.3 ± 1.5 a. u.[7] The system's orbit semi-major axis estimate is 104+28 −72a. u.[7]
Component A
The primary (brighter) component (SDSS J141624.08+134826.7 is its full designation; also known as SDSS J1416+13A) is a brown dwarf of spectral type sdL7,[2] or L6,[3][4][7] or L5,[6] or d/sdL7.[5] It has unusually blue near-infrared J−KS color.[5][4][6][13] According to Cushing et al. 2010, its peculiar spectrum is primarily a result of thin condensateclouds, and also vertical mixing occurs in its atmosphere.[9] However, in Burgasser et al., 2010 it was suggested that its (as well as component's B) peculiarities arise from age or metallicity, rather than cloud properties alone (since both A and B components have common peculiarities).[13]
Component B
The secondary (fainter) component (ULAS J141623.94+134836.3, abbreviated to ULAS J1416+1348, also known as SDSS J1416+13B) is a brown dwarf of spectral type T7.5,[13][15][16] or T7.5p.[5][7] It has unusually extremely blue near-infrared color H−K,[5] very red optical-to-near-infrared color (z−Y > +2.3 and z−J > +3.1),[4] and extremely red color H−[4.5] = 4.86 ± 0.04[5] (it was suggested, that the latter may be explained by presence of a cooler unresolved companion to SDSS J1416+13B).[5] Also, its spectrum indicates high surface gravity and/or subsolar metallicity.[13]
^ abKirkpatrick, 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. S2CID119279752.