WISEPC J045853.90+643451.9
Coordinates: 
04h 58m 53.93s, +64° 34′ 52.72″
 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][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: 196.8 ± 29.1[2] mas/yr Dec.: 159.3 ± 29.1[2] mas/yr |
| Distance | ~35.9[4][5] ly (~11[4][5] 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 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 | |
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 36 ly from Earth.[4][5]
Contents |
Discovery [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 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)[6]), 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]
Distance [edit]
Trigonometric parallax of WISE 0458+6434 is not yet measured. Therefore, there are only distance estimates of this object, obtained by indirect means (see table).
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][7] | |
| Kirkpatrick et al. (2011) (spectrophotometric, assuming a single source) |
~7.3 | ~23.8 | [1] | |
| Gelino et al. (2011), (according 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] |
Non-trigonometric distance estimates are marked in italic.
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. (2011) T/Y transition standard,[8] 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][8] — a compelling evidence for NH3 absorption.[4]
See also [edit]
The other five earliest brown dwarf discoveries from data collected by WISE:
- published by Burgasser et al. (2011):[6]
- 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[note 3])
- WISE 1322-2340 (T8, newfound)
- WISE 1614+1739 (T9, newfound)
- WISE 1617+1807 (T8, discovered before by Burgasser et al. (2011)[6])
- WISE 1627+3255 (T6, newfound)
- WISE 1653+4444 (T8, newfound)
- WISE 1741+2553 (T9, newfound)
Notes [edit]
- ^ a b c d e For an assumed system age of 1 Gyr.
- ^ a b This estimate is related to WISE 0458+6434 (not to component A individually), when its binarity was not yet uncovered.
- ^ 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 [edit]
- ^ a b c d e f g h i j k l 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:1108.4677v1. Bibcode:2011ApJS..197...19K. doi:10.1088/0067-0049/197/2/19.
- ^ a b c d e f g h i j k 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:1011.2279. Bibcode:2011ApJ...726...30M. doi:10.1088/0004-637X/726/1/30.
- ^ 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:1106.3142. Bibcode:2011AJ....142...57G. doi:10.1088/0004-6256/142/2/57.
- ^ a b c d e f g h i j k l m n o p q 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:1110.4664. Bibcode:2012ApJ...745...26B. doi:10.1088/0004-637X/745/1/26.
- ^ a b c d e f g Kirkpatrick, 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.
- ^ 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:1104.2537. Bibcode:2011ApJ...735..116B. doi:10.1088/0004-637X/735/2/116.
- ^ WISE: First Ultra-cool Brown Dwarf
- ^ 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)". arXiv:1108.4678v1 [astro-ph.SR]. Bibcode 2011ApJ...743...50C. doi:10.1088/0004-637X/743/1/50.
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