J/ApJS/173/104 Stellar population in Chamaeleon I (Luhman, 2007)
The stellar population of the Chamaeleon I star-forming region.
Luhman K.L.
<Astrophys. J. Suppl. Ser., 173, 104-136 (2007)>
=2007ApJS..173..104L 2007ApJS..173..104L
ADC_Keywords: Effective temperatures ; Photometry, RI ; Extinction ;
Photometry, infrared ; Stars, pre-main sequence ; YSOs
Keywords: infrared: stars - stars: evolution - stars: formation
stars: low-mass, brown dwarfs - stars: pre-main sequence
stars: luminosity function, mass function
Abstract:
I present a new census of the stellar population in the ChamaeleonI
star-forming region. Using optical and near-IR photometry and
follow-up spectroscopy, I have discovered 50 new members of
ChamaeleonI, expanding the census of known members to 226 objects.
Fourteen of these new members have spectral types later than M6, which
doubles the number of known members that are likely to be substellar.
I have estimated extinctions, luminosities, and effective temperatures
for the known members, used these data to construct an H-R diagram for
the cluster, and inferred individual masses and ages with the
theoretical evolutionary models of Baraffe and Chabrier. The low-mass
stars are more widely distributed than members at other masses in the
northern subcluster, but this is not the case in the southern
subcluster. Meanwhile, the brown dwarfs have the same spatial
distribution as the stars out to a radius of 3° (8.5pc) from the
center of ChamaeleonI.
Description:
Optical and near-IR broadband photometry from several sources (2MASS
and DENIS for IK1 & IK2) were used to perform four surveys (IK1, RI,
IK2, IZ). For RI, on the night of 2004 January 11, R- and I-band
images obtained with the Inamori Magellan Areal Camera and
Spectrograph (IMACS) on the Magellan I telescope at Las Campanas
Observatory were used. Deep optical and near-IR images of the densest
portion of the southern subcluster that were obtained by Luhman et al.
(2005ApJ...635L..93L 2005ApJ...635L..93L,) collected with the Advanced Camera for Surveys
(ACS) aboard HST through the F775W and F850LP filters were used for IZ.
Objects:
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RA (2000) DE Designation(s)
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11 53 -79.1 NAME CHA I = NAME CHAMAELEON 1 CLOUD
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 87 193 Photometry for Candidate Members in
Spectroscopic Sample
table3.dat 138 50 New Members of Chamaeleon I
table4.dat 138 163 Nonmembers
table5.dat 138 32 Previously Known Members of Chamaeleon I
with New Spectroscopy
table6.dat 78 215 Derived Properties for Members of Chamaeleon I
refs.dat 43 17 References
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See also:
J/A+A/416/555 : Brown Dwarfs in ChaI Dark Cloud (Lopez-Marti+ 2004)
J/AJ/124/1001 : JHKs photometry of Cha I variables (Carpenter, 2002)
J/AJ/121/974 : JHK photometry in Cha I (Gomez+, 2001)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 A21 --- Name Name (G1)
23- 27 F5.2 mag Rmag ?=- R band Magnitude
29- 33 F5.2 mag Imag ?=- I band Magnitude
35- 39 F5.2 mag imag ?=- DENIS i band Magnitude from 2d release
41- 45 F5.2 mag F775W ?=- F775W magnitude from ACS-HST
(∼i' from SDSS)
47- 51 F5.2 mag F850LP ?=- F850LP magnitude from ACS-HST
(∼z' from SDSS)
53- 57 F5.2 mag Jmag2 ?=- 2MASS J band Magnitude
59- 63 F5.2 mag Hmag2 ?=- 2MASS H band Magnitude
65- 69 F5.2 mag Ksmag2 ?=- 2MASS Ks band Magnitude
71- 75 F5.2 mag Jmag ?=- measured J band Magnitude with ISPI (2)
77- 81 F5.2 mag Hmag ?=- measured H band Magnitude with ISPI (2)
83- 87 F5.2 mag Ksmag ?=- measured Ks band Magnitude with ISPI (2)
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Note (2): ISPI: Infrared Side Port Imager at the 4m Blanco telescope at CTIO
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Byte-by-byte Description of file: table[345].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 A21 --- Name Name (G1)
22 A1 --- n_Name [df] Note on the object (1)
24- 51 A28 --- OName Other designation (2)
53 A1 --- n_OName [e] Separation of 1.1" and position angle
of 19° relative to T39A
55- 56 A2 --- l_SpType [<≥ ] Limit flag on Spectral Type
57- 82 A26 --- SpType Spectral Type (3)
84 A1 --- n_SpType [efgh] Note on Spectral Type (4)
86-104 A19 --- Memb Membership evidence (5)
106-110 A5 --- Sel Basis of selection (6)
112-124 A13 --- Night Night(s) number
126-138 A13 --- Refs References (detailed in refs.dat)
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Note (1): Note as follows:
d = Selected for spectroscopy because it appeared as a candidate member
in Fig. 2
f = Possible wide companion to T26 (Reipurth & Zinnecker,
1993A&A...278...81R 1993A&A...278...81R; Ghez et al., 1997ApJ...481..378G 1997ApJ...481..378G).
Note (2): Sources that are not in the 2MASS Point Source Catalog have been
assigned coordinate-based identifications.
Note (3): Uncertainties are ±0.25 subclass unless noted otherwise.
Note (4): Note as follows:
e = Spectral features suggest a surface gravity intermediate between
those of Chamaeleon I members and field dwarfs.
f = Classified as a background giant by
Brandner & Zinnecker (1997A&A...321..220B 1997A&A...321..220B).
g = Classified as an M-type member of Chamaeleon I by
Gomez & Mardones (2003AJ....125.2134G 2003AJ....125.2134G).
h = Classified as M5.5V by Comeron et al. (2004A&A...417..583C 2004A&A...417..583C).
Note (5): Membership evidence as follows:
AV = position above the main sequence for the distance of Chamaeleon I
e = strong emission lines
NaK = NaI and KI strengths intermediate between those of dwarfs and giants
ex = IR excess emission
H2O = shape of the gravity-sensitive steam bands
Li = strong Li absorption
rv = radial velocity similar to that of the known members of Chamaeleon I
Note (6): Note as follows:
Unc = previous classifications were uncertain
Comp = previously identified candidate companions
IK1 = candidate members in Fig.2
IK2 = candidate members in Fig.3
RI = candidate members in Fig.4
IZ = candidate members in Fig.5
2M = 2MASS photometry
IRAC = Spitzer photometry
X-ray = X-ray emission
LM04 = candidate members identified by
Lopez-Marti et al. (2004, Cat. J/A+A/416/555)
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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- 21 A21 --- Name Name (G1)
23- 43 A21 --- OName Other designation
45- 46 A2 --- l_SpType [≥ ] Limit flag on spectral type
47- 51 A5 --- SpType Adopted spectral type
53- 54 A2 --- l_Teff [≤ ] Limit flag on Teff
55- 59 I5 K Teff Effective temperature, scale from
Luhman et al. (2003, Cat. J/ApJ/593/1093)
61- 64 F4.2 mag AJ Extinction in J band
66- 73 F8.5 solLum Lbol Bolometric luminosities
75- 78 A4 --- IMF [1,2 ] Initial Mass Functions (1)
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Note (1): Note as follows:
1 = included in the IMFs in Fig.15 for the 1.5°x0.35°
2 = included in the IMFs in Fig.1 for the 0.22°x0.28°
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Number of reference
4- 22 A19 --- BibCode Bibcode
24- 43 A20 --- Aut Author's name
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Global notes:
Note (G1): the designations are:
2M JHHMMSSss+DDMMSSs = 2MASS JHHMMSSss+DDMMSSs or
Cha JHHMMSSss+DDMMSSs = [L2007b] Cha JHHMMSSss+DDMMSSs in Simbad.
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History:
* 15-Jun-2009: From electronic version of the journal
* 23-Nov-2012: In VizeiR table (memb), codes for "Previoulsy known members"
and "Nonmembers" corrected (initially inverted)
(End) Emmanuelle Perret [CDS] 13-May-2009