WISEPC J121756.91+162640.2

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Coordinates: Sky map 12h 17m 56.96s, +16° 26′ 39.98″

WISEPC J121756.91+162640.2
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[2]
Apparent magnitude (J (2MASS filter system) >18.52[1]
Apparent magnitude (J (MKO filter system) 17.83 ± 0.02[1][2]
Apparent magnitude (H (2MASS filter system) >17.50[1]
Apparent magnitude (H (MKO filter system) 18.18 ± 0.05[1][2]
Apparent magnitude (KS (2MASS filter system) >16.64[1]
Apparent magnitude (K (MKO filter system) 18.80 ± 0.04[2]
Component A
Spectral type T9[2]
Apparent magnitude (Y (MKO filter system) 18.59 ± 0.04[2]
Apparent magnitude (J (MKO filter system) 17.98 ± 0.02[2]
Apparent magnitude (H (MKO filter system) 18.31 ± 0.05[2]
Apparent magnitude (K (MKO filter system) 18.94 ± 0.04[2]
Component B
Spectral type Y0[2]
Apparent magnitude (Y (MKO filter system) 20.26 ± 0.04[2]
Apparent magnitude (J (MKO filter system) 20.08 ± 0.03[2]
Apparent magnitude (H (MKO filter system) 20.51 ± 0.06[2]
Apparent magnitude (K (MKO filter system) 21.10 ± 0.12[2]
Astrometry
Proper motion (μ) RA: 786 ± 42[3] mas/yr
Dec.: -1224 ± 27[3] mas/yr
Parallax (π) 99 ± 16[3] mas
Distance approx. 33 ly
(approx. 10 pc)
Orbit[2]
Primary A
Companion B
Period (P) 120+220
−30
—210+380
−50
yr
Details
Component A
Mass (11.5 ± 1.1)—(35 ± 3)[2] MJup
Luminosity (bolometric) 10−5.95 ± 0.18[2] L
Surface gravity (log g) (4.39 ± 0.03)—(5.07 ± 0.05)[2] cgs
Temperature (490 ± 30)—(660 ± 40)[2] K
Component B
Mass (5.5 ± 1.2)—(20 ± 2)[2] MJup
Luminosity (bolometric) 10−6.79 ± 0.18[2] L
Surface gravity (log g) (4.07 ± 0.10)—(4.77 ± 0.05)[2] cgs
Temperature (350 ± 40)—(470 ± 30)[2] K
Position (relative to A)
Component B
Epoch of observation UT 2012 January 29
Angular distance 758.2 ± 1.4 mas [2]
Position angle 14.50 ± 0.13° [2]
Observed separation
(projected)
~ 8 AU [2]
Other designations
Whole system:
WISEPC J121756.91+162640.2[1]
WISE J1217+1626[1][2]
WISE 1217+1626[1]
WISE J1217+1626AB[2]

Component A:
WISE J1217+1626A[2]

Component B:
WISE J1217+1626B[2]

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,[2] located in constellation Coma Berenices at approximately 33 light-years from Earth.[3]

History of observations[edit]

Discovery[edit]

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 satelliteNASA 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[edit]

Initial estimate of WISE 1217+1626' spectral type (before discovery of its binarity) was T9[1][4] (the same as the component's A type estimate made after this discovery).[2]

Discovery of component B[edit]

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.[2]

Distance[edit]

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.[3] 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 [4]
Liu et al. (2012) 10.5 ± 1.7 34.2 ± 5.5 [2]
Dupuy & Kraus (2013) 99 ± 16[~ 2] 10.1+1.9
−1.4
32.9+6.4
−4.6
[3]

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

Space motion[edit]

WISE 1217+1626 has proper motion of about 1455 milliarcseconds per year.[3]

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 [3]

The most accurate estimates are marked in bold.

Physical properties[edit]

Using three models, Liu et al. calculated physical properties of WISE 1217+1626 components.[2]

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[edit]

The other two brown dwarf binary systems, observed by Liu et al. with Keck II LGS-AO in 2012:[2]

Notes[edit]

  1. ^ 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.
  2. ^ Relative parallax.

References[edit]

  1. ^ a b c d e f g h i j k l m n o p 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.  edit
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj 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.  edit
  3. ^ a b c d e f g h 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.
  4. ^ a b 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.  edit