WISEPC J045853.90+643451.9

Coordinates: 04h 58m 53.93s, +64° 34′ 52.72″

WISEPC J045853.90+643451.9

WISE 0458+6434 is the small green dot in the centre.
Observation data
Epoch MJD 55453.42[1]      Equinox J2000[1]
Constellation Camelopardalis
Right ascension 04h 58m 53.93s[1]
Declination 64° 34′ 52.72″[1]
Characteristics
Whole system
Apparent magnitude (Y (FanCam)) 18.34 ± 0.07[2]
Apparent magnitude (J (2MASS filter system)) 17.47 ± 0.05[1]
Apparent magnitude (H (2MASS filter system)) 17.41 ± 0.06[1]
Component A
Spectral type T8.5[3]
Apparent magnitude (J (MKO filter system)) 17.50 ± 0.09[3]
Apparent magnitude (H (MKO filter system)) 17.81 ± 0.13[3]
Component B
Spectral type T9[3]
Apparent magnitude (J (MKO filter system)) 18.48 ± 0.12[3]
Apparent magnitude (H (MKO filter system)) 18.81 ± 0.17[3]
Astrometry
Proper motion (μ) RA: 185 ± 141[1] mas/yr
Dec.: 118 ± 149[1] mas/yr
Distance 34.2 ± 4.6[3] ly
(10.5 ± 1.4[3] pc)
Orbit[3]
Primary A
Companion B
Period (P) ~70[note 1] yr
Details
Component A
Mass 15[3][note 1] MJup
Surface gravity (log g) 5.0—5.5[2][note 2]
Temperature 600[3][note 1] K
Metallicity 0 ([Fe/H])[2][note 2]
Component B
Mass 10[3][note 1] MJup
Temperature 500[3][note 1] K
Position (relative to A)
Component B
Epoch of observation UT 2010 Mar 24
Angular distance 510 ± 20 mas [3]
Position angle 320 ± 1° [3]
Observed separation
(projected)		 5 ± 0.4 AU [3]
Other designations
WISEPA J045853.89+643452.9[1], WISE J0458+6434[1], WISE 0458+6434[1]

WISEPC J045853.90+643451.9 (designation is abbreviated to WISE 0458+6434) is a binary system of two (A and B) ultracool brown dwarfs of spectral classes T8.5 and T9, respectively[3], located in constellation Camelopardalis. It is one of two binary brown dwarf systems (along with WISE 1841+7000)[3] among 104 brown dwarfs systems, discovered in 2011 by the Wide-field Infrared Survey Explorer[1], also it was the first discovered of this 104 systems[2]. First distance estimate of this object, when its binary nature was not yet revealed, was between 6—10 pc[2] (~ 18—30 ly away[4], or, more precisely, assuming that one parsec contains not 3 light-years, but 3.261564, ~ 19.6—32.6 ly). Actually, this estimate is composed of two: spectrophotometric (6—8 pc, or 19.6—26.1 ly[2]), and photometric (9.0 ± 1.9 pc, or 29.4 ± 6.2 ly). Subsequently, near-infrared imaging observations using Laser Guide Star Adaptive Optics system (LGS-AO) on Keck II had shown binarity of WISE 0458+6434[3], and the system's distance was re-estimated in far direction: 10.5 ± 1.4 pc, or 34.2 ± 4.6 ly[3] (however, strangely, the (Kirkpatrick et al, 2011) article claims that this revised distance is 12.3 ± 2.3 pc, or 40.1 ± 7.5 ly[1]). Another (photometric) distance estimate is 7,3 pc (23,8 ly)[1], but, it still does not assume the system's binarity. The system's components estimated temperature is 600 K, or 327 °C (A)[3] and 500 K, or 227 °C (B)[3], both cooler than Venus. However, according proposed T/Y transition standard[5], WISE J0458+6434's components do not relate to Y-type, but both are of late T-type.

See also

Notes

  1. ^ a b c d e For an assumed system age of 1 Gyr.
  2. ^ a b This estimate is related to WISE 0458+6434 (not to component A individually), when its binarity was not yet uncovered.

References

  1. ^ a b c d e f g h i j k l m n Kirkpatrick, J. Davy; Cushing; Gelino; Griffith; Skrutskie; Marsh; Wright; Mainzer; Eisenhardt; McLean; Thompson; Bauer; Benford; Bridge; Lake; Petty; Stanford; Tsai; Bailey; Beichman; Bochanski; Burgasser; Capak; Cruz; Hinz; Kartaltepe; Knox; Manohar; Masters; Morales-Calderуnn; Prato; Rodigas; Salvato; Schurr; Scoville; Simcoe; Stapelfeldt; Stern; Stock; Vacca (2011). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". arXiv:1108.4677v1 [astro-ph.SR]. 
  2. ^ a b c d e f Mainzer; Cushing; Skrutskie; Gelino; Kirkpatrick; Jarrett; Masci; Marley; Saumon; Wright; Beaton; Dietrich; Eisenhardt; Garnavich; Kuhn; Leisawitz; Marsh; McLean; Padgett; Rueff (2010). "The First Ultra-Cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer". arXiv:1011.2279v1 [astro-ph.GA]. 
  3. ^ a b c d e f g h i j k l m n o p q r s t u v Gelino; Kirkpatrick; Cushing; Eisenhardt; Griffith; Mainzer; Marsh; Skrutskie; Wright (2011). "WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System". arXiv:1106.3142v1 [astro-ph.SR]. 
  4. ^ WISE: First Ultra-cool Brown Dwarf
  5. ^ Cushing, Michael C.; Kirkpatrick; Gelino; Griffith; Skrutskie; Mainzer; Marsh; Beichman; Burgasser; Prato; Simcoe; Marley; Saumon; Freedman; Eisenhardt; Wright (2011). "THE DISCOVERY OF Y DWARFS USING DATA FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE)". arXiv:1108.4678v1 [astro-ph.SR]. 
Bayer
Flamsteed
Nearby