WISE 0458+6434

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Coordinates: Sky map 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]
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][4][5]
Apparent magnitude (J (MKO filter system)) 17.50 ± 0.07[4]
Apparent magnitude (H (MKO filter system)) 17.77 ± 0.11[4]
Component B
Spectral type T9.5[4][5]
Apparent magnitude (J (MKO filter system)) 18.48 ± 0.07[4]
Apparent magnitude (H (MKO filter system)) 18.79 ± 0.11[4]
Proper motion (μ) RA: 136 ± 45[6] mas/yr
Dec.: 317 ± 22[6] mas/yr
Parallax (π) 70 ± 19[6] mas
Distance approx. 50 ly
(approx. 14 pc)
Primary A
Companion B
Period (P) ~70[~ 1] yr
Component A
Mass 15[3][~ 1] MJup
Surface gravity (log g) 5.0—5.5[2][~ 2] cgs
Temperature 600[3][~ 1] K
Metallicity 0 ([Fe/H])[2][~ 2]
Component B
Mass 10[3][~ 1] MJup
Temperature 500[3][~ 1] K
Position (relative to A)
Component B
Epoch of observation UT 2011 August 29
Angular distance 455.1 ± 4.2 mas [4]
Position angle 322.9 ± 0.4° [4]
Observed separation
5 ± 0.4 AU [3]
Other designations
WISEPC J045853.90+643451.9[2]
WISEPA J045853.89+643452.9[1]
WISE J0458+6434[1]
WISE 0458+6434[1]
WISEPC J0458+64[2]

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][5] located in constellation Camelopardalis at approximately 47 ly from Earth.[6]

History of observations[edit]


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 satelliteNASA 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]

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]), among which also was WISE 0458+6434.[1]

Discovery of the component B[edit]

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] Component B is also of late T-type — T9.5[4] (initially was estimated as T9).[3]


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
pc, or 46.6+17.4

WISE 0458+6434 distance estimates

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

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

Space motion[edit]

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

WISE 0458+6434 proper motion estimates

Source μ,
P. A.,
Mainzer et al. (2011) 253 51 196.8 ± 29.1 159.3 ± 29.1 [2]
Kirkpatrick et al. (2011) 219 57 185 ± 141 118 ± 149 [1]
Dupuy & Kraus (2013) 347 ± 26 23 ± 7 136 ± 45 317 ± 22 [6]

The most accurate estimates are marked in bold.

Physical properties[edit]

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

NH3 in the spectrum of component B[edit]

According proposed by Cushing et al. in 2011 T/Y transition standard,[9] 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][9] — a compelling evidence for NH3 absorption.[4]

See also[edit]

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]


  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.
  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).


  1. ^ a b c d e f g h i j k l m 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:1108.4677v1free to read. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19. 
  2. ^ a b c d e f g h i j Mainzer, A.; Cushing, Michael C.; Skrutskie, M.; Gelino, C. R.; Kirkpatrick, J. Davy; Jarrett, T.; Masci, F.; Marley, Mark S.; Saumon, D.; Wright, E.; Beaton, R.; Dietrich, M.; Eisenhardt, P.; Garnavich, P.; Kuhn, O.; Leisawitz, D.; Marsh, K.; McLean, I.; Padgett, D.; Rueff, K. (2011). "The First Ultra-cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer". The Astrophysical Journal. 726 (1): 30. arXiv:1011.2279free to read. Bibcode:2011ApJ...726...30M. doi:10.1088/0004-637X/726/1/30. 
  3. ^ a b c d e f g h i j k l m Gelino, Christopher R.; Kirkpatrick, J. Davy; Cushing, Michael C.; Eisenhardt, Peter R.; Griffith, Roger L.; Mainzer, Amanda K.; Marsh, Kenneth A.; Skrutskie, Michael F.; Wright, Edward L. (2011). "WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System". The Astronomical Journal. 142 (2): 57. arXiv:1106.3142free to read. Bibcode:2011AJ....142...57G. doi:10.1088/0004-6256/142/2/57. 
  4. ^ a b c d e f g h i j k l m n Burgasser, Adam J.; Gelino, Christopher R.; Cushing, Michael C.; Kirkpatrick, J. Davy (2012). "Resolved Spectroscopy of a Brown Dwarf Binary at the T Dwarf/Y Dwarf Transition". The Astrophysical Journal. 745 (1): 26. arXiv:1110.4664free to read. Bibcode:2012ApJ...745...26B. doi:10.1088/0004-637X/745/1/26. 
  5. ^ a b c d Kirkpatrick, J. D.; Gelino, C. R.; Cushing, M. C.; Mace, G. N.; Griffith, R. L.; Skrutskie, M. F.; Marsh, K. A.; Wright, E. L.; Eisenhardt, P. R.; McLean, I. S.; Mainzer, A. K.; Burgasser, A. J.; Tinney, C. G.; Parker, S.; Salter, G. (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:1205.2122free to read. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156. 
  6. ^ a b c d e f g h Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492. arXiv:1309.1422free to read. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. 
  7. ^ a b c Burgasser, Adam J.; Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Looper, Dagny L.; Tinney, Christopher; Simcoe, Robert A.; Bochanski, John J.; Skrutskie, Michael F.; Mainzer, A.; Thompson, Maggie A.; Marsh, Kenneth A.; Bauer, James M.; Wright, Edward L. (2011). "Fire Spectroscopy of Five Late-type T Dwarfs Discovered with the Wide-field Infrared Survey Explorer". The Astrophysical Journal. 735 (2): 116. arXiv:1104.2537free to read. Bibcode:2011ApJ...735..116B. doi:10.1088/0004-637X/735/2/116. 
  8. ^ WISE: First Ultra-cool Brown Dwarf
  9. ^ a b 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)". The Astrophysical Journal. 743 (1): 50. arXiv:1108.4678free to read. Bibcode:2011ApJ...743...50C. doi:10.1088/0004-637X/743/1/50.