J/AJ/130/188 Young stars in Trumpler 37 and NGC 7160 (Sicilia-Aguilar+, 2005)
Cepheus OB2: disk evolution and accretion at 3-10 Myr.
Sicilia-Aguilar A., Hartmann L.W., Hernandez J., Briceno C., Calvet N.
<Astron. J., 130, 188-209 (2005)>
=2005AJ....130..188S 2005AJ....130..188S
ADC_Keywords: Photometry, UBVRI ; Photometry, infrared ; Spectral types ;
Equivalent widths ; Stars, pre-main sequence
Keywords: accretion, accretion disks - planetary systems: protoplanetary disks -
stars: pre-main-sequence
Abstract:
We present the results of MMT observations of young stars for our
study of protoplanetary disks at ages 1-10Myr in two young clusters
located in the Cepheus OB2 region: Trumpler 37 (embedded in the HII
region IC 1396) and NGC 7160. Using low-resolution optical spectra
from the Hectospec multifiber spectrograph, we have tripled the number
of known low-mass cluster members, identifying 130 new members in
Tr 37 and 30 in NGC 7160. We use indicators of youth (Li absorption at
6707Å) and accretion/chromospheric activity (Hα emission) to
identify and classify the low-mass cluster members. We derive spectral
types for all the low-mass candidates and calculate the individual
extinctions and the average over the clusters.
Description:
We carried out our optical observations at the Fred Lawrence Whipple
Observatory (FLWO) in Mount Hopkins, Arizona, between 2000 and 2003.
We obtained optical VRcIc (hereafter VRI) and ultraviolet U photometry
using the 4-Shooter CCD camera mounted on the 1.2m telescope.
Objects:
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RA (2000) DE Designation(s)
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21 38 08.7 +57 26 48 Cl Trumpler 37 = IC 1396
21 53 36 +62 36 00 NGC 7160 = C 2152+623
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 166 Summary of optical and near-IR observations for
low-mass stars in Tr 37
table2.dat 86 35 Summary of optical and near-IR observations for
low-mass stars in NGC 7160
table3.dat 79 191 Summary of spectroscopy, extinction and membership
for low-mass stars in Tr 37
table4.dat 76 53 Summary of spectroscopy, extinction and membership
for low-mass stars in NGC 7160
table5.dat 89 58 Summary of optical, near-IR and spectroscopic data
for high- and intermediate-mass stars in Tr 37
table6.dat 99 26 Summary of optical, near-IR, and spectroscopic
observations for G-type intermediate-mass stars
in NGC 7160
table7.dat 99 70 Summary of optical, near-IR, and spectroscopic data
for high- and intermediate-mass stars (spectral
types BAF) in NGC 7160
table8.dat 38 68 U photometry and mass accretion rates in Tr 37
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See also:
J/AJ/128/805 : Low-mass stars in the Cepheus OB2 region (Sicilia-Aguilar+ 2004)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- [SHB2004] The 4Shooter identification (G1)
9- 24 A16 --- 2MASS 2MASS identification
26- 31 F6.3 mag Vmag ? The V band magnitude (1)
33- 38 F6.3 mag V-Rc ? The (V-R)c color index (1)
40- 44 F5.3 mag V-Ic ? The (V-I)c color index (1)
46- 51 F6.3 mag Jmag The J band magnitude
53- 57 F5.3 mag e_Jmag ? Error in Jmag (2)
59- 64 F6.3 mag Hmag The H band magnitude
66- 70 F5.3 mag e_Hmag ? Error in Hmag (2)
72- 77 F6.3 mag Kmag The K band magnitude
79- 83 F5.3 mag e_Kmag ? Error in Kmag (2)
85- 86 A2 --- Var Variability code (3)
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Note (1): Photometric errors in the 4Shooter visual magnitudes are very small,
the larger deviations are produced by the intrinsic variability of
the stars.
Note (2): Lack of definite errors in 2MASS is an indication of possible
problems in the photometry.
Note (3): Variability code, defined as follows:
RI = observed significant variability (over 3σ) in both R & I bands;
I = observed significant variability in I band;
NO = no significant (over 3σ) variations detected in our variability
study.
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- [SHB2004] The 4Shooter identification (G1)
9- 24 A16 --- 2MASS 2MASS identification
26- 30 A5 --- Inst Instrument
32- 38 A7 --- SpType Spectral type (1)
40- 42 F3.1 --- e_SpType ? Uncertainty in SpType (2)
44- 49 F6.1 0.1nm EW(Ha) ? Equivalent width of Hα (3)
51- 56 F6.1 0.1nm EW(Li) ? Equivalent width of Li(6707Å) (3)
58- 59 A2 --- TType T Tauri type (4)
61- 63 F3.1 mag AV ? Visual extinction
65- 68 F4.1 Myr Age ? Age (5)
70- 71 A2 --- Mem Member? (G2)
73- 79 A7 --- Com Additional comments (6)
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Note (1): Given the better quality of Hectospec spectra, they were given
preference for obtaining spectral types.
Note (2): Errors in the spectral types are given in number of subtypes.
Note (3): In units of Angstroms.
Note (4): Referred to the type of TTS, they denote the objects with Hα
in the limit between CTTS and WTTS according to White & Basri (2003,
ApJ...582.1109W).
Colon denotes uncertain values.
Note (5): Derived using the Siess (2000A&A...358..593S 2000A&A...358..593S) isochrones in the V vs.
V-I diagram.
Note (6): Additional comments, defined as follows:
Yg = "maybe younger", meaning it is over the 1Myr isochrone in the
V vs. V-I diagram;
L = JHK colors consistent with the CTTS locus;
IR = IRAC/MIPS excess consistent with a disk Sicilia-Aguilar et al.
Paper III in preparation (2005);
BS = Stars which are in the binary sequence;
: = uncertain.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name The 4Shooter identification (1)
13- 28 A16 --- 2MASS 2MASS identification
30- 34 F5.2 mag Bmag The B band magnitude (2)
36- 40 F5.2 mag Vmag The V band magnitude (2)
42- 47 F6.3 mag Jmag ? The J band magnitude
49- 53 F5.3 mag e_Jmag ? Error in Jmag (3)
55- 60 F6.3 mag Hmag ? The H band magnitude
62- 66 F5.3 mag e_Hmag ? Error in Hmag (3)
68- 73 F6.3 mag Kmag ? The K band magnitude
75- 79 F5.3 mag e_Kmag ? Error in Kmag
81- 82 A2 --- SpType Spectral Type (4)
84- 86 F3.1 mag AV Visual extinction
88- 89 A2 --- Mem Member? (5)
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Note (1): MVA-NNN : Cl* Trumpler 37 MVA NNN in Simbad
KUN-NNN : Cl* Trumpler 37 KUN NNN in Simbad
CCDM+5734: CCDM J21377+5734AB in Simbad
SBZ-2-46 : Cl* IC 1396 SBZ 2-46 in Simbad
tr37-185 : Cl Trumpler 37 185 in Simbad
Note (2): Photometry from Contreras et al. (2002AJ....124.1585C 2002AJ....124.1585C),
Marshall & van Altena (1987AJ.....94...71M 1987AJ.....94...71M),
Kun et al. (1987Ap&SS.134..211K 1987Ap&SS.134..211K).
Note (3): Non-defined error in 2MASS photometry is an indication of probable
problems.
Note (4): Spectral type for KUN-314S is not well defined; its extinction is
considered to be the mean of the cluster; membership is proved by
the emission lines in the spectrum. No 2MASS counterpart was found
within 2arcsec of MVA-276. All spectra were taken with the FAST slit
spectrograph on the 1.5m telescope. Spectral types from
Contreras et al. (2002AJ....124.1585C 2002AJ....124.1585C).
Note (5): Based on average extinction for the cluster and its standard
deviation (confirmed members=Y if extinction is within 1σ of the
average, most likely members=P if extinction is within 1-2σ of
the average, most likely non members=PN if extinction is within
2-3σ of the average).
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name The 4Shooter identification (G1) (G3)
9- 24 A16 --- 2MASS 2MASS identification
26- 31 F6.3 mag Vmag The V band magnitude (G4)
33- 38 F6.3 mag V-R The (V-R) color index (G4)
40- 44 F5.3 mag V-I The (V-I) color index (G4)
46- 51 F6.3 mag Jmag The J band magnitude
53- 57 F5.3 mag e_Jmag Error in Jmag
59- 64 F6.3 mag Hmag The H band magnitude
66- 70 F5.3 mag e_Hmag Error in Hmag
72- 77 F6.3 mag Kmag The K band magnitude
79- 83 F5.3 mag e_Kmag Error in Kmag
85- 88 A4 --- SpType Spectral Type
90- 92 F3.1 --- e_SpType Error in SpType
94- 96 F3.1 mag AV Visual extinction
98- 99 A2 --- Memb Member? (G2)
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name The 4Shooter identification (G1) (G3) (1)
9- 24 A16 --- 2MASS 2MASS identification
26- 31 F6.3 mag Vmag The V band magnitude (G4) (2)
33- 38 F6.3 mag U-B The (U-B) color index (G4) (2)
40- 44 F5.3 mag B-V The (B-V) color index (G4) (2)
46- 51 F6.3 mag Jmag The J band magnitude
53- 57 F5.3 mag e_Jmag Error in Jmag
59- 64 F6.3 mag Hmag The H band magnitude
66- 70 F5.3 mag e_Hmag Error in Hmag
72- 77 F6.3 mag Kmag The K band magnitude
79- 83 F5.3 mag e_Kmag Error in Kmag
85- 88 A4 --- SpType Spectral Type
90- 92 F3.1 --- e_SpType Error in SpType
94- 96 F3.1 mag AV Visual extinction
98- 99 A2 --- Memb Member? (G2)
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Note (1): All spectra were taken with FAST, and spectral types were derived
using the scheme described in the text.
Note (2): Photometry is from De Graeve (1983VatOP...2....1D 1983VatOP...2....1D).
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- [SHB2004] The 4Shooter identification (G1)
9- 13 F5.2 mag Umag The U band magnitude
15- 19 F5.3 solLum LU The U band excess luminosity (1)
21- 25 F5.3 solLum LAcc ? The accretion band luminosity (1)
27- 32 F6.3 10-8solMass/yr dM/dt ? Accretion rate
33 A1 --- u_dM/dt Uncertainty flag on dM/dt (2)
35- 38 I4 --- Epoch Observational epoch (3)
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Note (1): In solar units. Excess U luminosity measures only the excess
luminosity in U over what would be expected for each spectral type.
The total luminosity, calculated from I photometry and the
bolometric correction corresponding to each spectral type
Kenyon & Hartmann (1995, Cat. J/ApJS/101/117). See text and
Gullbring et al. (1998ApJ...492..323G 1998ApJ...492..323G).
Note (2): Denotes measured values of U band excess at the detection limit,
which may be considered cautiously.
Note (3): Some stars were observed in the two epochs, or included in two
overlapping fields during the same observing run, and have therefore
multiple U measurements.
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Global Notes:
Note (G1): Nomenclature note:
NN-NNNNN: [SHB2004] Trumpler 37 NN-NNNN in tables 1, 3, and 8
[SHB2004] NGC 7160 NN-NNNN in tables 2, 4 and 6
DG-NNNN: Cl* NGC 7160 DG NNNN in table 7.
Note (G2): Membership code, defined as follows:
Y = confirmed member,
P = probable member,
PN = probable non-member.
Note (G3): Spectroscopic data from FAST. All the stars listed here are found
to be WTTS (no Hα emission).
Note (G4): Photometric errors in the 4Shooter visual magnitudes are very small,
the larger deviations are produced by the intrinsic variability of
the stars.
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History:
From electronic version of the journal
References:
Sicilia-Aguilar et al., Paper I 2004AJ....128..805S 2004AJ....128..805S, Cat. J/AJ/128/805
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 20-Oct-2005