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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
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: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 21 38 08.7 +57 26 48 Cl Trumpler 37 = IC 1396 21 53 36 +62 36 00 NGC 7160 = C 2152+623 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
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 79 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
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
Bytes Format Units Label Explanations
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)
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.
Byte-by-byte Description of file: table3.dat table4.dat
Bytes Format Units Label Explanations
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 Halpha (3) 51- 56 F6.1 0.1nm EW(Li) ? Equivalent width of Li(6707AA) (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)
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) 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.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
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)
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), Marshall & van Altena (1987AJ.....94...71M), Kun et al. (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). 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).
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
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)
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
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)
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).
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
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)
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). 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.
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.
History: From electronic version of the journal References: Sicilia-Aguilar et al., Paper I 2004AJ....128..805S, Cat. J/AJ/128/805
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 20-Oct-2005
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