WISE 0458+6434

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

WISEPC J045853.90+643451.9
WISE2010-040-rotate180.jpg
WISE 0458+6434 is the small green dot in the centre.
Observation data
Epoch MJD 55453.42[1]:{{{3}}}      Equinox J2000[1]:{{{3}}}
Constellation Camelopardalis
Right ascension 04h 58m 53.93s[1]:{{{3}}}
Declination 64° 34′ 52.72″[1]:{{{3}}}
Characteristics
Whole system
Apparent magnitude (Y (FanCam)) 18.34 ± 0.07[2]:{{{3}}}
Apparent magnitude (J (2MASS filter system)) 17.47 ± 0.05[1]:{{{3}}}
Apparent magnitude (H (2MASS filter system)) 17.41 ± 0.06[1]:{{{3}}}
Component A
Spectral type T8.5[3]:{{{3}}}[4]:{{{3}}}[5]:{{{3}}}
Apparent magnitude (J (MKO filter system)) 17.50 ± 0.07[4]:{{{3}}}
Apparent magnitude (H (MKO filter system)) 17.77 ± 0.11[4]:{{{3}}}
Component B
Spectral type T9.5[4]:{{{3}}}[5]:{{{3}}}
Apparent magnitude (J (MKO filter system)) 18.48 ± 0.07[4]:{{{3}}}
Apparent magnitude (H (MKO filter system)) 18.79 ± 0.11[4]:{{{3}}}
Astrometry
Proper motion (μ) RA: 136 ± 45[6]:{{{3}}} mas/yr
Dec.: 317 ± 22[6]:{{{3}}} mas/yr
Parallax (π) 70 ± 19[6]:{{{3}}} mas
Distance approx. 50 ly
(approx. 14 pc)
Orbit[3]:{{{3}}}
Primary A
Companion B
Period (P) ~70[~ 1]:{{{3}}} yr
Details
Component A
Mass 15[3]:{{{3}}}[~ 1]:{{{3}}} MJup
Surface gravity (log g) 5.0—5.5[2]:{{{3}}}[~ 2]:{{{3}}} cgs
Temperature 600[3]:{{{3}}}[~ 1]:{{{3}}} K
Metallicity 0 ([Fe/H])[2]:{{{3}}}[~ 2]:{{{3}}}
Component B
Mass 10[3]:{{{3}}}[~ 1]:{{{3}}} MJup
Temperature 500[3]:{{{3}}}[~ 1]:{{{3}}} K
Position (relative to A)
Component B
Epoch of observation UT 2011 August 29
Angular distance 455.1 ± 4.2 mas [4]:{{{3}}}
Position angle 322.9 ± 0.4° [4]:{{{3}}}
Observed separation
(projected)		 5 ± 0.4 AU [3]:{{{3}}}
Other designations
WISEPC J045853.90+643451.9[2]:{{{3}}}
WISEPA J045853.89+643452.9[1]:{{{3}}}
WISE J0458+6434[1]:{{{3}}}
WISE 0458+6434[1]:{{{3}}}
WISEPC J0458+64[2]:{{{3}}}

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 T9.5, respectively,[4]:{{{3}}}[5]:{{{3}}} located in constellation Camelopardalis at approximately 47 ly from Earth.[6]:{{{3}}}

History of observations

Discovery

WISE 0458+6434 A was discovered in 2010 by A. Mainzer et al. 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.

In 2010 Mainzer et al. had conducted follow-up observations of WISE 0458+6434:

on 2010 March 17 (UT) YJH photometry with FanCam, an infrared imager operating at the University of Virginia’s Fan Mountain 31 in telescope;
on 2010 March 19 (UT) 1.5—2.3 μm spectroscopy with LUCIFER near-infrared camera/spectrograph at the Large Binocular Telescope (LBT);
on 2010 Sep 12 (UT) 0.8—2.5 μm spectroscopy with SpeX on the 3.0 m NASA Infrared Telescope Facility on Mauna Kea.

In early 2011 Mainzer et al. published a paper in The Astrophysical Journal, where they presented discovery of one new found by WISE brown dwarf — ultra-cool object WISE 0458+6434. This object became the first brown dwarf, found by WISE.[2]:{{{3}}}

Several months later, also in 2011, Kirkpatrick et al. published a paper in The Astrophysical Journal Supplement, where they presented characteristics of 104 first discovered by WISE brown dwarf systems — 98 new found systems and six systems, presented in published earlier papers (one in Mainzer et al. (2011), and five in Burgasser et al. (2011)[7]:{{{3}}}), among which also was WISE 0458+6434.[1]:{{{3}}}

Discovery of the component B

WISE 0458+6434 B was discovered in 2011 by Gelino et al., when they examined for binarity nine brown dwarfs using Laser Guide Star Adaptive Optics system (LGS-AO) on Keck II telescope on Mauna Kea; seven of these nine brown dwarfs were also newfound, and two were discovered before, including WISE 0458+6434. These observations had indicated that two of these nine brown dwarfs, including WISE 0458+6434, are binary. Angular separation of WISE 0458+6434 components was 80 mas.[3]:{{{3}}} Component B is also of late T-type — T9.5[4]:{{{3}}} (initially was estimated as T9).[3]:{{{3}}}

Distance

Currently the most accurate distance estimate of WISE 0458+6434 is a trigonometric parallax, measured using Spitzer Space Telescope and published in 2013 by Trent Dupuy and Adam Kraus: 0.070 ± 0.019 arcsec, corresponding to a distance 14.3+5.3
−3.0 pc, or 46.6+17.4
−9.9 ly.[6]:{{{3}}}

WISE 0458+6434 distance estimates

Source Parallax, mas Distance, pc Distance, ly Ref.
Mainzer et al. (2011)
(spectrophotometric)		 6—8 19.6—26.1 [2]:{{{3}}}
Mainzer et al. (2011)
(photometric)		 9.0 ± 1.9 29.4 ± 6.2 [2]:{{{3}}}
Mainzer et al. (2011)
(combined)		 6—10 19.6—32.6 [2]:{{{3}}}[8]
Kirkpatrick et al. (2011)
(spectrophotometric,
assuming a single source)		 ~7.3 ~23.8 [1]:{{{3}}}
Gelino et al. (2011),
(according Kirkpatrick et al. (2011),
Appendix I.)		 12.3 ± 2.3 40.1 ± 7.5 [1]:{{{3}}}
Gelino et al. (2011) 10.5 ± 1.4 34.2 ± 4.6 [3]:{{{3}}}
Burgasser et al. (2012)
(component A)		 10.5 ± 1.8 34.2 ± 5.9 [4]:{{{3}}}
Burgasser et al. (2012)
(component B)		 11.2 ± 2.2 36.5 ± 7.2 [4]:{{{3}}}
Burgasser et al. (2012)
(combined A + B)		 ~11 ~35.9 [5]:{{{3}}}
Dupuy & Kraus (2013) 70 ± 19[~ 3]:{{{3}}} 14.3+5.3
−3.0		 46.6+17.4
−9.9		 [6]:{{{3}}}

Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.

Space motion

WISE 0458+6434 has proper motion of about 347 milliarcseconds per year.[6]:{{{3}}}

WISE 0458+6434 proper motion estimates

Source μ,
mas/yr		 P. A.,
°		 μRA,
mas/yr		 μDEC,
mas/yr		 Ref.
Mainzer et al. (2011) 253 51 196.8 ± 29.1 159.3 ± 29.1 [2]:{{{3}}}
Kirkpatrick et al. (2011) 219 57 185 ± 141 118 ± 149 [1]:{{{3}}}
Dupuy & Kraus (2013) 347 ± 26 23 ± 7 136 ± 45 317 ± 22 [6]:{{{3}}}

The most accurate estimates are marked in bold.

Physical properties

The brown dwarfs' temperature estimates are 600 K, or 327 °C (A)[3]:{{{3}}} and 500 K, or 227 °C (B),[3]:{{{3}}} both cooler than Venus.

NH3 in the spectrum of component B

According proposed by Cushing et al. in 2011 T/Y transition standard,[9]:{{{3}}} WISE J0458+6434 B does not relate to Y-type. However, its spectrum has feature similar to those in the spectra of the Y0 dwarfs WISE 1405+5534 and WISE 1738+2732, which were tentatively attributed to NH3 (ammonia) absorption[4]:{{{3}}}[9]:{{{3}}} — a compelling evidence for NH3 absorption.[4]:{{{3}}}

See also

The other five earliest brown dwarf discoveries from data collected by WISE:

The other eight objects, checked for binarity by Gelino et al. (2011) on Keck II:[3]:{{{3}}}

Notes

  1. ↑ 1.0 1.1 1.2 1.3 1.4 For an assumed system age of 1 Gyr.
  2. ↑ 2.0 2.1 This estimate is related to WISE 0458+6434 (not to component A individually), when its binarity was not yet uncovered.
  3. ↑ Relative parallax.
  4. ↑ Presented in Gelino et al. (2011), but this is not mentioned in Kirkpatrick et al. (2011) and Kirkpatrick et al. (2012) — according these two articles, the only discovery paper of WISE 0750+2725 is Kirkpatrick et al. (2011).

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ 5.0 5.1 5.2 5.3 Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ 7.0 7.1 7.2 Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ WISE: First Ultra-cool Brown Dwarf
  9. ↑ 9.0 9.1 Lua error in package.lua at line 80: module 'strict' not found.
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