J/ApJ/867/109 Spitzer observations of Y and T dwarfs (Martin+, 2018)
Y dwarf trigonometric parallaxes from the Spitzer Space Telescope.
Martin E.C., Kirkpatrick J.D., Beichman C.A., Smart R.L., Faherty J.K.,
Gelino C.R., Cushing M.C., Schneider A.C., Wright E.L., Lowrance P.,
Ingalls J., Tinney C.G., McLean I.S., Logsdon S.E., Lebreton J.
<Astrophys. J., 867, 109 (2018)>
=2018ApJ...867..109M 2018ApJ...867..109M
ADC_Keywords: Parallaxes, trigonometric ; Stars, brown dwarf; Stars, Y-type;
Stars, T-type; Magnitudes, absolute ; Photometry, infrared ;
Spectral types; Proper motions
Keywords: parallaxes ; brown dwarfs ;
stars: individual (WISE J033605.04-014351.0)
Abstract:
Y dwarfs provide a unique opportunity to study free-floating objects
with masses <30MJup and atmospheric temperatures approaching those
of known Jupiter-like exoplanets. Obtaining distances to these objects
is an essential step toward characterizing their absolute physical
properties. Using Spitzer's Infrared Array Camera (IRAC) [4.5] images
taken over baselines of ∼2-7yrs, we measure astrometric distances for
22 late-T and early Y dwarfs, including updated parallaxes for 18
objects and new parallax measurements for 4 objects. These parallaxes
will make it possible to explore the physical parameter space occupied
by the coldest brown dwarfs. We also present the discovery of six new
late-T dwarfs, updated spectra of two T dwarfs, and the
reclassification of a new Y dwarf, WISE J033605.04-014351.0, based on
Keck/NIRSPEC J-band spectroscopy. Assuming that effective temperatures
are inversely proportional to absolute magnitude, we examine trends in
the evolution of the spectral energy distributions of brown dwarfs
with decreasing effective temperature. Surprisingly, the Y dwarf class
encompasses a large range in absolute magnitude in the near- to
mid-infrared photometric bandpasses, demonstrating a larger range of
effective temperatures than previously assumed. This sample will be
ideal for obtaining mid-infrared spectra with the James Webb Space
Telescope because their known distances will make it easier to measure
absolute physical properties.
Description:
This catalogue includes Spitzer photometry for 27 objects, including
preliminary parallaxes for 19 Y dwarfs and 3 late-T dwarfs from the
Spitzer parallax program (PI: Kirkpatrick, aiming to measure distances
to all of the nearby late-T and Y dwarfs within 20pc that are not
being covered by ground-based astrometric monitoring). The Spitzer
observations are obtained with the with Spitzer/Infrared Array Camera
(IRAC) channel 2, and they cover baselines of ∼2-7years.
Besides, near-infrared images of WISE 0336-0143, WISE0550-1950,
WISE0615+1526, WISE 0642+0423, WISE 1055-1652, WISE 1220+5407, and
WISE 2203+4619 were obtained using the WIRC on the 200 inch Hale
Telescope at Palomar Observatory on 2012 January 4 (WISE 0336-0143,
WISE 1055-1652), 2014 March 7 (WISE 2203+4619) and 2016 February 26
(WISE 0550-1950, WISE 0615+1526, WISE 0642+0423, WISE 1220+5407). WIRC
has a pixel scale of 0.2487"/pixel providing a total field of view of
8.7". For each object, fifteen 2-minute images were obtained in the J
filter (30 minutes total exposure time).
The catalogue also includes spectral types of four targets from the
original Spitzer Parallax Program with unknown or uncertain spectral
types: WISE 0336-0143, WISE 1051-2138, WISE 1055-1652, and WISE
1318-1758. These types were obtained using J-band spectroscopic
observations (R∼1500) at the NIRSPEC instrument at the W. M. Keck
Observatory (see section 3.2 for further details).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 212 27 Coordinates, spectral types, and photometry of
target objects
table3.dat 90 27 Spitzer observations
table4.dat 71 307 Target coordinates at each epoch
table5.dat 133 22 Best-fit astrometric solutions
table6.dat 114 22 Absolute magnitudes
img/* . 9 Individual FITS files of Palomar WIRC images
for 7 stars
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
II/328 : AllWISE Data Release (Cutri+ 2013)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/493/L27 : Parallaxes of 10 ultracool subdwarfs (Schilbach+, 2009)
J/AJ/153/14 : Sun-neighborhood XXXVIII Nearby M dwarf systems (Winters+,2017)
J/AJ/154/147 : Astrometry&photometry late-type dwarfs&subdwarfs (Dahn+, 2017)
J/ApJ/752/56 : DKP. III. Parallaxes for 70 ultracool dwarfs (Faherty+, 2012)
J/ApJ/753/156 : T/Y brown dwarfs with WISE photometry (Kirkpatrick+, 2012)
J/ApJ/783/122 : AllWISE motion survey (Kirkpatrick+, 2014)
J/ApJ/810/158 : M,L,T dwarfs fundamental param and SEDs (Filippazzo+,2015)
J/ApJ/833/96 : Hawaii IR parallax program. II. Ultracool dwarfs (Liu+, 2016)
J/ApJ/842/118 : Brown dwarfs with spectral type later than T6 (Leggett+, 2017)
J/ApJ/858/55 : K2 ultracool dwarfs survey. III. M6-L0 flares (Paudel+, 2018)
J/ApJS/197/19 : First brown dwarfs discovered by WISE (Kirkpatrick+, 2011)
J/ApJS/201/19 : Hawaii Infrared Parallax Program. I. (Dupuy+, 2012)
J/ApJS/205/6 : T dwarf population revealed by WISE (Mace+, 2013)
J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)
J/AJ/157/101 : Cloud Atlas: HST/WFC3 NIR spectral library (Manjavacas+, 2019)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- WISEA WISEA designation (JHHMMSS.ss+DDMMSS.s)
20- 21 A2 --- m_WISEA Component on WISEA J014656.66+423409.9
23- 36 A14 --- Name Short WISE based Name
38- 38 A1 --- n_WISEA Note on Source (1)
40- 47 A8 --- SpT Infrared Spectral Type(s)
49- 49 A1 --- n_SpT Note(s) on SpT (1)
51- 51 I1 --- r_SpT [1/7] Reference for SpT (2)
53- 53 A1 --- l_JMKO Limit flag for JMKO
54- 59 F6.3 mag JMKO [17.6/23.5] MKO J band magnitude
61- 65 F5.3 mag e_JMKO [0.01/0.3]? Uncertainty in JMKO
67- 67 A1 --- n_JMKO Note on JMKO (1)
69- 69 A1 --- l_HMKO Limit flag for HMKO
70- 75 F6.3 mag HMKO [17.7/23.4]? MKO H band magnitude
77- 81 F5.3 mag e_HMKO [0.02/0.4]? Uncertainty in HMKO
83- 83 A1 --- n_HMKO Note on HMKO (1)
85- 87 A3 --- r_JMKO Reference for JMKO, HMKO (2)
89- 89 A1 --- l_W1mag Limit flag for W1mag
90- 95 F6.3 mag W1mag [16.4/19.6] WISE W1 band magnitude
97-101 F5.3 mag e_W1mag [0.07/0.6]? Uncertainty in W1mag
103-108 F6.3 mag W2mag [13.5/15.8] WISE W2 band magnitude
110-114 F5.3 mag e_W2mag [0.03/0.2] Uncertainty in W2mag
116-121 F6.3 mag W3mag [16/17.9] WISE W3 band magnitude
123-127 F5.3 mag e_W3mag [0.01/0.2] Uncertainty in W3mag
129-134 F6.3 mag W4mag [13.6/15.7] WISE W4 band magnitude
136-140 F5.3 mag e_W4mag [0.01/0.03] Uncertainty in W4mag
142-176 A35 --- FileJ Name of the FITS file in subdirectory img
(Palomar WIRC J-band); column added by CDS
178-212 A35 --- FileH Name of the FITS file in subdirectory img
(Palomar WIRC H-band); column added by CDS
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Note (1): Source Notes as follows:
a = Object WISEA J014656.66+423409.9AB is a known binary, so the
combined-light magnitudes are not used elsewhere in this paper;
b = See Section 3.3 for discussion on the spectral type of
WISEAJ033605.04-014351.0;
c = Photometry of WISEA J131833.96-175826.3 is on the 2MASS system, not
on MKO (Mauna Kea Observatories). These values are not used
elsewhere in this paper because the two photometric systems are
not comparable;
d = WISEA J154151.65-225024.9 does not appear in the AllWISE Source
Catalog, so WISE data are drawn from the WISE All-Sky Source
Catalog instead. See Kirkpatrick et al. (2012, J/ApJ/753/156) for
discussion regarding the possible erroneous W1 measurement for
this object.
Note (2): References to spectral types and JH photometry as follows:
1 = This paper;
2 = Kirkpatrick et al. (2012, J/ApJ/753/156);
3 = Cushing et al. (2011ApJ...743...50C 2011ApJ...743...50C);
4 = Kirkpatrick et al. (2014, J/ApJ/783/122);
5 = Schneider et al. (2015ApJ...804...92S 2015ApJ...804...92S);
6 = Tinney et al. (2012ApJ...759...60T 2012ApJ...759...60T);
7 = Cushing et al. (2014AJ....147..113C 2014AJ....147..113C);
8 = Dupuy et al. (2015ApJ...803..102D 2015ApJ...803..102D);
9 = Leggett et al. (2013ApJ...763..130L 2013ApJ...763..130L);
10 = Leggett et al. (2015ApJ...799...37L 2015ApJ...799...37L);
11 = Mace et al. (2013, J/ApJS/205/6).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1-14 A14 --- Name Short WISE based Name
16-20 I5 --- PID1 First Spitzer Program number
21 A1 --- --- [(]
22-23 I2 --- n_PID1 Number of [4.5] epochs for PID1
24 A1 --- --- [)]
26-30 I5 --- PID2 ? Second Spitzer Program number
31 A1 --- --- [(]
32-33 I2 --- n_PID2 ? Number of [4.5] epochs for PID2
34 A1 --- --- [)]
36-40 I5 --- PID3 ? Third Spitzer Program number
41 A1 --- --- [(]
42-43 I2 --- n_PID3 ? Number of [4.5] epochs for PID3
44 A1 --- --- [)]
46-50 I5 --- PID4 ? Fourth Spitzer Program number
51 A1 --- --- [(]
52-53 I2 --- n_PID4 ? Number of [4.5] epochs for PID4
54 A1 --- --- [)]
56-62 F7.1 d MJDlo [55387.3/57175.2] Lower range of
Modified Julian Date of Spitzer observation
63 A1 --- --- [-]
64-70 F7.1 d MJDup [56768.1/57175.3]? Upper range of
Modified Julian Date of Spitzer observation
72-79 I8 --- AOR1 First astronomical observation request
number for photometry
81-88 I8 --- AOR2 ? Second astronomical observation
request number for photometry
90 A1 --- f_Name Flag on Name (3)
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Note (3): Flas as follows:
a = WISE 1639-6847: This high motion object was blended with a background
star during our original observation in program 80109. We reacquired
this observation during program 11059 to make up for the loss of a
[4.5] astrometric epoch and the loss of our sole [3.6] photometric
data point.
b = WISE 1828+265: The [3.6] and [4.5] observations of this
object in program 551 were broken into separate AORs but were
observed concurrently.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Short WISE based Name
16- 29 F14.10 deg RAdeg [26.735/335.231] Target location in
Right Ascension (J2000)
31- 45 F15.11 deg DEdeg [-75.007/84.02] Target location in
Declination (J2000)
47- 51 F5.3 arcsec e_RAdeg [0.01/0.03] Uncertainty in RAdeg
53- 57 F5.3 arcsec e_DEdeg [0.01/0.03] Uncertainty in DEdeg
59- 71 F13.7 --- MJD [55387.3/57175.3] Modified Julian Date of
observation; JD-2400000.5
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Short WISE based Name
16- 25 F10.6 deg RAdeg [26.735/335.231] Right Ascension,
decimal degrees, (J2000) at Ep=2014.0
27- 36 F10.6 deg DEdeg [-75.007/84.02] Declination, decimal
degrees, (J2000) at Ep=2014.0
38- 42 F5.2 mas e_RAdeg [4.5/93.2] Positional Uncertainty, RAdeg
44- 48 F5.2 mas e_DEdeg [4.3/10.1] Positional Uncertainty, DEdeg
50- 58 F9.3 mas/yr pmRA [-2337/1200] Proper motion, Right Ascension
60- 64 F5.2 mas/yr e_pmRA [3/13] Uncertainty in pmRA
66- 73 F8.2 mas/yr pmDE [-3105/536] Proper motion, Declination
75- 79 F5.2 mas/yr e_pmDE [3/13] Uncertainty in pmDE
81- 87 F7.3 mas plx [45/229] Trigonometric parallax, relative
89- 92 F4.2 mas e_plx [3.8/9.3] Uncertainty in plx
94- 98 F5.2 pc Dist [4.3/22] Distance (from plx)
100-104 F5.3 pc E_Dist [0.1/3.8] Upper uncertainty in Dist
106-110 F5.3 pc e_Dist [0.1/2.8] Lower uncertainty in Dist
112-113 I2 mas ePos [15/30] Positional uncertainty for
astrometric solution
115-116 I2 --- Nep [10/16] Number of positional epochs
118-119 I2 --- Nref [7/96] Number of reference stars
121-125 F5.2 --- chi2 [9.8/34] χ^2 fit statistic
127-128 I2 --- DOF [14/27] Degrees of Freedom in fit
130-133 F4.2 --- chi2r [0.4/1.7] Reduced χ^2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Short WISE based Name
16- 22 F7.3 mas plx [45/229] Trigonometric parallax
24- 27 F4.2 mas e_plx [3.8/9.3] Uncertainty in plx
29- 33 F5.2 pc Dist [4.3/22] Distance (from plx)
35- 39 F5.3 pc E_Dist [0.1/3.8] Upper uncertainty in Dist
41- 45 F5.3 pc e_Dist [0.1/2.8] Lower uncertainty in Dist
47- 47 A1 --- l_JMag Limit flag on Jmag
48- 52 F5.2 mag JMag [16.8/23.8] Absolute 2MASS J magnitude
54- 57 F4.2 mag e_JMag [0.06/0.4]? Uncertainty in Jmag
59- 59 A1 --- l_HMag Limit flag on Hmag
60- 64 F5.2 mag HMag [16.1/23.7] Absolute 2MASS H magnitude
66- 69 F4.2 mag e_HMag [0.07/0.5]? Uncertainty in Hmag
71- 75 F5.2 mag 3.6Mag [14.9/19] Absolute Spitzer IRAC/Channel 1
(3.6um) magnitude
77- 80 F4.2 mag e_3.6Mag [0.07/0.4] Uncertainty in 3.6mag
82- 86 F5.2 mag 4.5Mag [13.1/15.9] Absolute Spitzer IRAC/Channel 2
(4.5um) magnitude
88- 91 F4.2 mag e_4.5Mag [0.06/0.4] Uncertainty in 4.5mag
93- 93 A1 --- l_W1Mag Limit flag on W1mag
94- 98 F5.2 mag W1Mag [15.7/20] Absolute WISE/W1 magnitude
100-103 F4.2 mag e_W1Mag [0.1/7]? Uncertainty in W1mag
105-109 F5.2 mag W2Mag [13/16] Absolute WISE/W2 magnitude
111-114 F4.2 mag e_W2Mag [0.07/0.4] Uncertainty in W2mag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie FIX [CDS] 14-Oct-2019