WISEPC J121756.91+162640.2
Coordinates: 
12h 17m 56.96s, +16° 26′ 39.98″
| Observation data Epoch MJD 55549.01[ 1] Equinox J2000[ 1] | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 12h 17m 56.96s[ 1] |
| Declination | 16° 26′ 39.98″[ 1] |
| Characteristics | |
| Whole system | |
| Apparent magnitude (Y (MKO filter system) | 18.38 ± 0.04[ 1] |
| Apparent magnitude (J (2MASS filter system) | >18.52[ 1] |
| Apparent magnitude (J (MKO filter system) | 17.83 ± 0.02[ 1][ 1] |
| Apparent magnitude (H (2MASS filter system) | >17.50[ 1] |
| Apparent magnitude (H (MKO filter system) | 18.18 ± 0.05[ 1][ 1] |
| Apparent magnitude (KS (2MASS filter system) | >16.64[ 1] |
| Apparent magnitude (K (MKO filter system) | 18.80 ± 0.04[ 1] |
| Component A | |
| Spectral type | T9[ 1] |
| Apparent magnitude (Y (MKO filter system) | 18.59 ± 0.04[ 1] |
| Apparent magnitude (J (MKO filter system) | 17.98 ± 0.02[ 1] |
| Apparent magnitude (H (MKO filter system) | 18.31 ± 0.05[ 1] |
| Apparent magnitude (K (MKO filter system) | 18.94 ± 0.04[ 1] |
| Component B | |
| Spectral type | Y0[ 1] |
| Apparent magnitude (Y (MKO filter system) | 20.26 ± 0.04[ 1] |
| Apparent magnitude (J (MKO filter system) | 20.08 ± 0.03[ 1] |
| Apparent magnitude (H (MKO filter system) | 20.51 ± 0.06[ 1] |
| Apparent magnitude (K (MKO filter system) | 21.10 ± 0.12[ 1] |
| Astrometry | |
| Proper motion (μ) | RA: 786 ± 42[ 1] mas/yr Dec.: -1224 ± 27[ 1] mas/yr |
| Parallax (π) | 99 ± 16[ 1] mas |
| Distance | approx. 33 ly (approx. 10 pc) |
| Orbit[ 1] | |
| Primary | A |
| Companion | B |
| Period (P) | 120+220 −30—210+380 −50 yr |
| Details | |
| Component A | |
| Mass | (11.5 ± 1.1)—(35 ± 3)[ 1] MJup |
| Luminosity (bolometric) | 10−5.95 ± 0.18[ 1] L☉ |
| Surface gravity (log g) | (4.39 ± 0.03)—(5.07 ± 0.05)[ 1] cgs |
| Temperature | (490 ± 30)—(660 ± 40)[ 1] K |
| Component B | |
| Mass | (5.5 ± 1.2)—(20 ± 2)[ 1] MJup |
| Luminosity (bolometric) | 10−6.79 ± 0.18[ 1] L☉ |
| Surface gravity (log g) | (4.07 ± 0.10)—(4.77 ± 0.05)[ 1] cgs |
| Temperature | (350 ± 40)—(470 ± 30)[ 1] K |
| Position (relative to A) | |
| Component | B |
| Epoch of observation | UT 2012 January 29 |
| Angular distance | 758.2 ± 1.4 mas [ 1] |
| Position angle | 14.50 ± 0.13° [ 1] |
| Observed separation (projected) | ~ 8 AU [ 1] |
| Other designations | |
WISEPC J121756.91+162640.2 (designation abbreviated to WISE 1217+1626, or WISE J1217+1626) is a binary brown dwarf system of spectral classes T9 + Y0,[ 1] located in constellation Coma Berenices at approximately 33 light-years from Earth.[ 1]
History of observations
Discovery
WISE 1217+1626 A was discovered in 2011 by J. Davy Kirkpatrick 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 2011 Kirkpatrick et al. published a paper in The Astrophysical Journal Supplement, where they presented discovery of 98 new found by WISE brown dwarf systems with components of spectral types M, L, T and Y, among which also was WISE 1217+1626.[ 1][~ 1]
Initial estimate of spectral type
Initial estimate of WISE 1217+1626' spectral type (before discovery of its binarity) was T9[ 1][ 1] (the same as the component's A type estimate made after this discovery).[ 1]
Discovery of component B
WISE 1217+1626 B was discovered in 2012 by Liu et al. with laser guide star (LGS) adaptive optics (AO) system of the 10-m Keck II Telescope on Mauna Kea, Hawai'i, using infra-red camera NIRC2 (the observations were made on 2012 January 29 (UT)). On 2012 April 1 (UT) Liu et al. observed WISE J1217+1626AB using the near-IR camera NIRI on the Gemini-North 8.1-m telescope on Mauna Kea, Hawai'i and the binary was marginally resolved. On 12 April 2012 (UT) they obtained resolved spectroscopy of WISE J1217+1626AB with the near-IR spectrograph NIRSPEC again on the Keck II Telescope. In 2012 Liu et al. published a paper in The Astrophysical Journal where they presented results of observations with Keck II LGS-AO of three brown dwarf binary systems, binarity of one of which was known before, and binarity of the other two, including WISE 1217+1626, was first presented in this paper.[ 1]
Distance
Currently the most accurate distance estimate of WISE 1217+1626 is a trigonometric parallax, measured using Spitzer Space Telescope and published in 2013 by Trent Dupuy and Adam Kraus: 0.099 ± 0.016 arcsec, corresponding to a distance 10.1+1.9
−1.4 pc, or 32.9+6.4
−4.6 ly.[ 1] In the estimates made before discovery of the component's B by Liu et al. in 2012 the binarity is not taken into account.
WISE 1217+1626 distance estimates
| Source | Parallax, mas | Distance, pc | Distance, ly | Ref. |
|---|---|---|---|---|
| Kirkpatrick et al. (2011) (not assuming binarity) | ~6.7 | ~21.9 | [ 1] | |
| Kirkpatrick et al. (2012) (not assuming binarity) | ~7.1 | ~23.2 | [ 1] | |
| Liu et al. (2012) | 10.5 ± 1.7 | 34.2 ± 5.5 | [ 1] | |
| Dupuy & Kraus (2013) | 99 ± 16[~ 2] | 10.1+1.9 −1.4 | 32.9+6.4 −4.6 | [ 1] |
Non-trigonometric distance estimates are marked in italic. The best estimate is marked in bold.
Space motion
WISE 1217+1626 has proper motion of about 1455 milliarcseconds per year.[ 1]
WISE 1217+1626 proper motion estimates
| Source | μ, mas/yr | P. A., ° | μRA, mas/yr | μDEC, mas/yr | Ref. |
|---|---|---|---|---|---|
| Kirkpatrick et al. (2011) | 1765 | 148 | 935 ± 269 | -1497 ± 279 | [ 1] |
| Dupuy & Kraus (2013) | 1455 ± 38 | 147.3 ± 1.3 | 786 ± 42 | -1224 ± 27 | [ 1] |
The most accurate estimates are marked in bold.
Physical properties
Using three models, Liu et al. calculated physical properties of WISE 1217+1626 components.[ 1]
From Burrows et al. (2003) models and M(J):
| Component and assumed age | Mass, MJup | Teff, K | log g, cm/s2 | P, yr |
|---|---|---|---|---|
| A (for 1 Gyr) | 11.5 ± 1.1 | 490 ± 30 | 4.39 ± 0.03 | |
| B (for 1 Gyr) | 7.4 ± 0.5 | 381 ± 13 | 4.18 ± 0.03 | 210+370 −50 |
| A (for 5 Gyr) | 29 ± 3 | 530 ± 30 | 4.95 ± 0.05 | |
| B (for 5 Gyr) | 18.4 ± 1.0 | 402 ± 11 | 4.68 ± 0.03 | 130+230 −30 |
From Lyon/COND models and M(J):
| Component and assumed age | Mass, MJup | Teff, K | log g, cm/s2 | P, yr |
|---|---|---|---|---|
| A (for 1 Gyr) | 14.4 ± 1.8 | 610 ± 40 | 4.54 ± 0.07 | |
| B (for 1 Gyr) | 35 ± 3 | 430 ± 30 | 4.27 ± 0.05 | 190+340 −50 |
| A (for 5 Gyr) | 8.3 ± 0.9 | 660 ± 40 | 5.07 ± 0.05 | |
| B (for 5 Gyr) | 20 ± 2 | 470 ± 30 | 4.77 ± 0.05 | 120+220 −30 |
From Lyon/COND models and Lbol:
| Component and assumed age | Mass, MJup | Teff, K | log g, cm/s2 | P, yr |
|---|---|---|---|---|
| A (for 1 Gyr) | 13 ± 3 | 580 ± 70 | 4.47 ± 0.10 | |
| B (for 1 Gyr) | 5.5 ± 1.2 | 350 ± 40 | 4.07 ± 0.10 | 210+380 −50 |
| A (for 5 Gyr) | 33 ± 5 | 630 ± 70 | 5.04 ± 0.09 | |
| B (for 5 Gyr) | 13 ± 3 | 370 ± 50 | 4.54 ± 0.11 | 130+240 −30 |
See also
The other two brown dwarf binary systems, observed by Liu et al. with Keck II LGS-AO in 2012:[ 1]
- WISE 1711+3500 (T8 + T9.5, binarity was newly discovered)
- CFBDSIR 1458+10 (T9 + Y0, binarity was known before)
Notes
- ↑ These 98 brown dwarf systems are only among first, not all brown dwarf systems, discovered from data, collected by WISE: six discoveries were published earlier (however, also listed in Kirkpatrick et al. (2011)) in Mainzer et al. (2011) and Burgasser et al. (2011), and the other discoveries were published later.
- ↑ Relative parallax.
References
- ↑ 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.
- ↑ 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:1205.2122. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156.
- ↑ Liu, Michael C.; Dupuy, Trent J.; Bowler, Brendan P.; Leggett, S. K.; Best, William M. J. (2012). "Two Extraordinary Substellar Binaries at the T/Y Transition and the Y-band Fluxes of the Coolest Brown Dwarfs". The Astrophysical Journal 758 (1): 57. arXiv:1206.4044. Bibcode:2012ApJ...758...57L. doi:10.1088/0004-637X/758/1/57.
- ↑ Dupuy, Trent J.; Kraus, Adam L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". arXiv:1309.1422v1 [astro-ph.SR]. Bibcode 2013arXiv1309.1422D.
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