J/AJ/130/1733 Optical spectroscopy of ρ Oph stars (Wilking+, 2005)
Optical spectroscopy of the surface population of the ρ Ophiuchi molecular
cloud: the first wave of star formation.
Wilking B.A., Meyer M.R., Robinson J.G., Greene T.P.
<Astron. J., 130, 1733-1751 (2005)>
=2005AJ....130.1733W 2005AJ....130.1733W
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Equivalent widths
Keywords: ISM: individual (ρ Ophiuchi cloud) -
open clusters and associations: individual (Upper Scorpius) -
stars: formation - stars: pre-main-sequence
Abstract:
We present the results of optical spectroscopy of 139 stars obtained
with the Hydra multiobject spectrograph. The objects extend over a
1.3°2 area surrounding the main cloud of the ρ Oph complex.
The objects were selected from narrowband images to have Hα in
emission. Using the presence of strong Hα emission, lithium
absorption, location in the Hertzsprung-Russell diagram, or previously
reported X-ray emission, we were able to identify 88 objects as young
stars associated with the cloud. Strong Hα emission was
confirmed in 39 objects with line widths consistent with their origin
in magnetospheric accretion columns. Two of the strongest
emission-line objects are young, X-ray-emitting brown dwarf candidates
with M8 spectral types. Comparisons of the bolometric luminosities and
effective temperatures with theoretical models suggest a median age
for this population of 2.1Myr, which is significantly older than the
ages derived for objects in the cloud core. It appears that these
stars formed contemporaneously with low-mass stars in the Upper
Scorpius subgroup, likely triggered by massive stars in the Upper
Centaurus subgroup.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 153 152 Optical properties of candidate T Tauri stars
table3.dat 140 45 Gaussian fits to emission lines of T Tauri stars
table4.dat 64 88 Association members
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See also:
J/A+A/359/113 : X-ray and IR study of Rho Oph dark cloud (Grosso+, 2000)
J/A+A/429/963 : XMM-Newton observation of the rho Oph cloud (Ozawa+, 2005)
J/ApJ/613/393 : X-ray and radio sources in ρ Oph Core A (Gagne+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Seq Identification number (N-NN) (G0)
6- 18 A13 --- Names Source names (G1)
20- 33 A14 --- XName X-Ray source identification (2)
35- 36 I2 h RAh Hour of Right Ascension (J2000)
38- 39 I2 min RAm Minute of Right Ascension (J2000)
41- 44 F4.1 s RAs Second of Right Ascension (J2000)
46 A1 --- DE- Sign of the Declination (J2000)
47- 48 I2 deg DEd Degree of Declination (J2000)
50- 51 I2 arcmin DEm Arcminute of Declination (J2000)
53- 56 F4.1 arcsec DEs Arcsecond of Declination (J2000)
58- 61 F4.2 --- CaH ? The CaH index (3)
63- 66 F4.2 --- TiO ? The TiO index (4)
68- 71 A4 0.1nm EWLi Equivalent width of Li (5)
73- 79 A7 0.1nm PEWHa Previous equivalent width if Hα (6)
81- 86 F6.2 0.1nm EWHa ? Equivalent width of Hα (5)
88- 92 F5.2 mag Icmag ? The Cousins I band magnitude
94- 97 F4.2 mag Rc-Ic ? The (Rc-Ic) color index
99-116 A18 --- PSpType Previous spectral type (7)
118-125 A8 --- SpType Spectral type
127-134 A8 --- ASpType Adopted spectral type
136-153 A18 --- Note Additional notes (8)
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Note (2): X-Ray source identification, defined as follows:
ROX = Montemerle et al. (ROX, 1983ApJ...269..182M 1983ApJ...269..182M);
ROXR1 = The ROSAT survey by Casanova et al. (ROXR1, 1996ApJ...439..752C 1996ApJ...439..752C);
ROXRA = The ROSAT survey by Grosso et al. (2000, Cat. J/A+A/359/113);
ROXRF = The ROSAT survey by Grosso et al. (2000, Cat. J/A+A/359/113);
ROXCH = The Chandra survey by Imanishi, Koyama & Tsuboi (2001ApJ...557..747I 2001ApJ...557..747I);
GDS = The Chandra survey by Gagne, Skinner & Daniel (2004,
Cat. J/ApJ/613/393).
ROXC = The Chandra survey by Grosso et al. (2005);
ROXN = The XMM-Newton survey by Ozawa, Grosso, & Montmerle (2005,
Cat. J/A+A/429/963).
Note (3): Calculated from the ratio of flux from the center of the continuum
at 7035Å to the center of the CaH absorption at 6975Å.
Note (4): Calculated from the ratio of flux from the center of the continuum
at 7035Å to the center of the TiO band at 7140Å.
Note (5): In units of Angstroms.
Note (6): By Cohen & Kuhi (1979ApJS...41..743C 1979ApJS...41..743C), Bouvier & Appenzeller
(1992A&AS...92..481B 1992A&AS...92..481B), or Martin et al. (1998MNRAS.300..733M 1998MNRAS.300..733M) and in
units of Angstroms.
Note (7): Previous spectral type by:
CK = Cohen & Kuhi (1979ApJS...41..743C 1979ApJS...41..743C);
BA = Bouvier & Appenzeller (1992A&AS...92..481B 1992A&AS...92..481B);
GM = Greene & Meyer (1995ApJ...450..233G 1995ApJ...450..233G);
MMGC = Martin et al. (1998MNRAS.300..733M 1998MNRAS.300..733M);
LR = Luhman & Rieke (1999ApJ...525..440L 1999ApJ...525..440L);
WGM = Wilking, Greene, & Meyer (1999AJ....117..469W 1999AJ....117..469W);
N02 = Natta et al. (2002A&A...393..597N 2002A&A...393..597N).
Note (8): Additional notes, defined as follows:
h = R and I band photometry from Gordon & K. Strom, unpublished
observations.
i = Radio continuum source at λ=6cm observed by Andre, Montmerle &
Feigelson (1987AJ.....93.1182A 1987AJ.....93.1182A), Leous et al. (1991ApJ...379..683L 1991ApJ...379..683L),
or Gagne, Skinner, & Daniel (2004, Cat. J/ApJ/613/393).
j = Denotes emission of the CaII triplet.
"db" indicates emission lines are split.
k = S/N in 6700Å region too low to detect Li absorption.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Seq Identification number (G0)
6- 17 A12 --- Names Source names (G1)
19- 22 F4.1 0.1nm EWHeI5876 ? Equivalent width of HeI(5876) (2)
23 A1 --- f_EWHeI5876 Flag on EWHeI5876 (3)
25- 27 I3 km/s FWHMHeI5876 ? FWHM of HeI(5876)
29- 31 F3.1 0.1nm EWOI6300 ? Equivalent width of [OI](6300) (4)
32 A1 --- f_EWOI6300 Flag on EWOI6300 (3)
34- 36 I3 km/s FWHMOI6300 ? FWHM of [OI](6300) (4)
38 A1 --- l_EWHa Limit flag on EWHa
39- 44 F6.1 0.1nm EWHa Equivalent width of Hα(6563) (2)
46- 48 I3 km/s FWHMHa FWHM of Hα(6563) (2)
50- 53 A4 --- TypeHa Hα type (5)
55- 58 F4.2 0.1nm EWHeI6678 ? Equivalent width of HeI(6678) (2)
59 A1 --- f_EWHeI6678 Flag on EWHeI6678 (3)
61- 63 I3 km/s FWHMHeI6678 ? FWHM of HeI (6678) (2)
65- 68 F4.2 0.1nm EWHeI7066 ? Equivalent width of HeI(7066) (2)
69 A1 --- f_EWHeI7066 Flag on EWHeI7066 (3)
71- 73 I3 km/s FWHMHeI7066 ? FWHM of HeI(7066) (2)
75- 78 F4.2 0.1nm EWOI7773 ? Equivalent width of OI(7773) (2)
79 A1 --- f_EWOI7773 Flag on EWOI7773 (3)
81- 83 I3 km/s FWHMOI7773 ? FWHM of OI(7773) (2)
84 A1 --- f_FWHMOI7773 Flag on FWHMOI7773 (3)
86- 89 F4.2 0.1nm EWOI8447 ? Equivalent width of OI(8447) (2)
90 A1 --- f_EWOI8447 Flag on EWOI8447 (3)
92- 94 I3 km/s FWHMOI8447 ? FWHM of OI(8447) (2)
96-100 F5.2 0.1nm EWCaII8498 ? Equivalent width of CaII(8498) (2)
101 A1 --- f_EWCaII8498 Flag on EWCaII8498 (3)
103-105 I3 km/s FWHMCaII8498 ? FWHM of CaII(8498) (2)
106 A1 --- f_FWHMCaII8498 [g] Flag on FWHMCaII8498 (3)
108-112 F5.2 0.1nm EWCaII8542 ? Equivalent width of CaII(8542) (2)
113 A1 --- f_EWCaII8542 Flag on EWCaII8542 (3)
115-117 I3 km/s FWHMCaII8542 ? FWHM of CaII(8542) (2)
118 A1 --- f_FWHMCaII8542 [g] Flag on FWHMCaII8542 (3)
120-122 F3.1 0.1nm EWPa14 ? Equivalent width of Pa 14(8598) (2)
123 A1 --- f_EWPa14 Flag on EWPa14 (3)
125-127 I3 km/s FWHMPa14 ? FWHM of Pa 14(8598) (2)
128 A1 --- f_FWHMPa14 Flag on FWHMPa14 (3)
130-134 F5.2 0.1nm EWCaII8662 ? Equivalent width of CaII(8662) (2)
135 A1 --- f_EWCaII8662 Flag on EWCaII8662 (3)
137-139 I3 km/s FWHMCaII8662 ? FWHM of CaII(8662) (2)
140 A1 --- f_FWHMCaII8662 [g] Flag on FWHMCaII8662 (3)
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Note (2): Of the emission line as determined from gaussian fits.
The fit parameters are greater than 5σ unless otherwise noted.
The values for FWHM have not been deconvolved by the instrumental
response. The equivalent widths are in units of Angstroms.
Note (3): Flag on FWHMCaII8662, defined as follows:
: = between 3σ and 5σ;
U = an upper limit;
f = Pa 19 at 8413Å was also detected in the spectrum of WL 18 with
Wλ=1.9:Å and Δv=180:km/s.
g = The CaII emission lines display double-peaked Type IIIB profiles
similar to Hα.
Note (4): The [OI] line at 6363Å is also observed in emission but is
much weaker. Otherwise the same as in Note (2).
Note (5): The profile shape of Hα as defined by Reipurth, Pedrosa
and Lago (1996A&AS..120..229R 1996A&AS..120..229R): symmetric (Type I), double-peaked with
the secondary peak greater than half the strength of the primary
(Type II), or double-peaked with the secondary peak less than half the
strength of the primary (Type III). The Roman numeral is followed by
"B" if the asymmetry is on the blue side, "R" if on the red side, or
"w" if the profile has non-gaussian wings.
Multiple gaussian fits were used to estimate the equivalent width for
Type II or III profiles. Equivalent widths for profiles with wings are
lower limits. Velocity widths for Type II or III profiles are not
well-defined.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Seq Identification number
6- 13 A8 --- Names Source names (G1)
15- 18 F4.1 mag AV ? The V band extinction
20 A1 --- f_AV [c] Flag on AV (2)
22- 26 F5.2 mag IMAG ? Absolute I band magnitude
28- 32 F5.3 [K] logTeff log of the effective temperature
34- 38 F5.2 [solLum] logLum ? log of the luminosity
40 A1 --- f_logLum [c] Flag on logLum (2)
42 A1 --- l_Mass Limit flag on Mass
43- 46 F4.2 solMass Mass ? Mass in solar units
48 A1 --- l_logA Limit flag on logA
49- 52 F4.2 [Myr] logA ? log of the age
54- 64 A11 --- Note Additional notes (3)
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Note (2): Due to strong emission lines in the R and I bands relative
to the continuum, AV and luminosity estimate is taken from Bontemps
et al. (2001A&A...372..173B 2001A&A...372..173B) using the (J-H) color and adjusted to a
distance of 150pc.
Note (3): Association membership established through the presence of
ha = Hα emission;
x = x-ray emission;
li = lithium absorption;
ext = location above the main sequence and Av>1.5mag.
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Global Notes:
Note (G0): HYDRA field and aperture number
Note (G1): Sources names from optical or infrared studies by:
SR = Struve & Rudkjobing (1949ApJ...109...92S 1949ApJ...109...92S);
DoAr = Dolidze & Arakelyan (1959SvA.....3..434D 1959SvA.....3..434D);
GSS = Grasdalen, Strom, & Strom (Source 1, 1973ApJ...184L..53G 1973ApJ...184L..53G);
VSSG = Vrba et al. (1975ApJ...197...77V 1975ApJ...197...77V);
VSS = Vrba, Strom, & Strom (1976AJ.....81..958V 1976AJ.....81..958V);
EL = Elias (1978ApJ...224..453E 1978ApJ...224..453E);
Chini = Chini (1981A&A....99..346C 1981A&A....99..346C);
WL = Wilking & Lada (1983ApJ...274..698W 1983ApJ...274..698W);
ROX = Montmerle et al. (1983ApJ...269..182M 1983ApJ...269..182M);
WSB = Wilking, Schwartz, & Blackwell (1987AJ.....94..106W 1987AJ.....94..106W);
WLY = Wilking, Lada, & Young (1989ApJ...340..823W 1989ApJ...340..823W);
GY = Greene & Young (1992ApJ...395..516G 1992ApJ...395..516G).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 29-Dec-2005