Astronomy:WISE 0458+6434
Coordinates: 
04h 58m 53.93s, +64° 34′ 52.72″
 WISE 0458+6434 is the small green dot in the centre. | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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][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] |
| Astrometry | |
| Proper motion (μ) | RA: 136 ± 45[6] mas/yr Dec.: 317 ± 22[6] mas/yr |
| Parallax (π) | 108.3 ± 1.7[7] mas |
| Distance | 30.1 ± 0.5 ly (9.2 ± 0.1 pc) |
| Orbit[7] | |
| Primary | A |
| Companion | B |
| Period (P) | 43+7 −12 yr |
| Semi-major axis (a) | 5+0.3 −0.6 au |
| Eccentricity (e) | 0.18+0.09 −0.18 |
| Inclination (i) | 76.5+1.5 −2.3° |
| Details | |
| 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 (projected) | 5 ± 0.4 AU [3] |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
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]
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)[8]), among which also was WISE 0458+6434.[1]
Discovery of the companion
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]
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]
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] | |
| Mainzer et al. (2011) (photometric) |
9.0 ± 1.9 | 29.4 ± 6.2 | [2] | |
| Mainzer et al. (2011) (combined) |
6–10 | 19.6–32.6 | [2][9] | |
| Kirkpatrick et al. (2011) (spectrophotometric, 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+5.3−3.0 | 46.6+17.4−9.9 | [6] |
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]
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] |
| 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
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
According proposed by Cushing et al. in 2011 T/Y transition standard,[10] 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][10] — a compelling evidence for NH3 absorption.[4]
See also
The other five earliest brown dwarf discoveries from data collected by WISE:
- published by Burgasser et al. (2011):[8]
- WISE 1617+1807 (T8, young and cloudy)
- WISE 1812+2721 (T8.5:, cloudless)
- WISE 2018-7423 (T7, possibly cloudy)
- WISE 2313-8037 (T8, also young and cloudy)
- WISE 2359-7335 (T5.5, cloudless)
The other eight objects, checked for binarity by Gelino et al. (2011) on Keck II:[3]
- binarity found:
- WISE 1841+7000 (T5 + T5, newfound)
- binarity not found:
- WISE 0750+2725 (T8.5, newfound[~ 4])
- WISE 1322–2340 (T8, newfound)
- WISE 1614+1739 (T9, newfound)
- WISE 1617+1807 (T8, discovered before by Burgasser et al. (2011)[8])
- WISE 1627+3255 (T6, newfound)
- WISE 1653+4444 (T8, newfound)
- WISE 1741+2553 (T9, newfound)
Notes
- ↑ 1.0 1.1 1.2 1.3 For an assumed system age of 1 Gyr.
- ↑ 2.0 2.1 This estimate is related to WISE 0458+6434 (not to component A individually), when its binarity was not yet uncovered.
- ↑ Relative parallax.
- ↑ 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
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L.; Mainzer, Amy K. et al. (2011). "The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal Supplement 197 (2): 19. doi:10.1088/0067-0049/197/2/19. Bibcode: 2011ApJS..197...19K.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Mainzer, Amy K.; Cushing, Michael C.; Skrutskie, Michael F.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Jarrett, Thomas H.; Masci, Frank; Marley, Mark S. et al. (2011). "The First Ultra-cool Brown Dwarf Discovered by the Wide-field Infrared Survey Explorer". The Astrophysical Journal 726 (1): 30. doi:10.1088/0004-637X/726/1/30. Bibcode: 2011ApJ...726...30M.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 Gelino, Christopher R.; Kirkpatrick, J. Davy; Cushing, Michael C.; Eisenhardt, Peter R.; Griffith, Roger L.; Mainzer, Amanda (Amy) K.; Marsh, Kenneth A.; Skrutskie, Michael F. et al. (2011). "WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System". The Astronomical Journal 142 (2): 57. doi:10.1088/0004-6256/142/2/57. Bibcode: 2011AJ....142...57G.
- ↑ 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 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. doi:10.1088/0004-637X/745/1/26. Bibcode: 2012ApJ...745...26B.
- ↑ 5.0 5.1 5.2 5.3 Kirkpatrick, J. Davy; Gelino, Christopher R.; Cushing, Michael C.; Mace, Gregory N.; Griffith, Roger L.; Skrutskie, Michael F.; Marsh, Kenneth A.; Wright, Edward L. et al. (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. doi:10.1088/0004-637X/753/2/156. Bibcode: 2012ApJ...753..156K.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Dupuy, Trent J.; Kraus, Adam L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science 341 (6153): 1492–5. doi:10.1126/science.1241917. PMID 24009359. Bibcode: 2013Sci...341.1492D.
- ↑ 7.0 7.1 Leggett, S. K.; Dupuy, Trent J.; Morley, Caroline V.; Marley, Mark S.; Best, William M. J.; Liu, Michael C.; Apai, D.; Casewell, S. L. et al. (2019-09-01). "3.8 μm Imaging of 400-600 K Brown Dwarfs and Orbital Constraints for WISEP J045853.90+643452.6AB". The Astrophysical Journal 882 (2): 117. doi:10.3847/1538-4357/ab3393. ISSN 0004-637X. Bibcode: 2019ApJ...882..117L.
- ↑ 8.0 8.1 8.2 Burgasser, Adam J.; Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Looper, Dagny L.; Tinney, Christopher; Simcoe, Robert A. et al. (2011). "Fire Spectroscopy of Five Late-type T Dwarfs Discovered with the Wide-field Infrared Survey Explorer". The Astrophysical Journal 735 (2): 116. doi:10.1088/0004-637X/735/2/116. Bibcode: 2011ApJ...735..116B.
- ↑ WISE: First Ultra-cool Brown Dwarf
- ↑ 10.0 10.1 Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R.; Griffith, Roger L.; Skrutskie, Michael F.; Mainzer, Amy K.; Marsh, Kenneth A.; Beichman, Charles A. et al. (2011). "The Discovery of Y Dwarfs using Data from the Wide-field Infrared Survey Explorer (WISE)". The Astrophysical Journal 743 (1): 50. doi:10.1088/0004-637X/743/1/50. Bibcode: 2011ApJ...743...50C.
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