J/ApJ/602/816 Chamaeleon I star-forming region census (Luhman, 2004)
A census of the Chamaeleon I star-forming region.
Luhman K.L.
<Astrophys. J., 602, 816-842 (2004)>
=2004ApJ...602..816L 2004ApJ...602..816L
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ;
Photometry, infrared
Keywords: infrared: stars - stars: evolution - stars: formation -
stars: low-mass, brown dwarfs -
stars: luminosity function, mass function - stars: pre-main-sequence
Abstract:
I present a new census of the members of the Chamaeleon I star-forming
region. Optical spectroscopy has been obtained for 179 objects that
have been previously identified as possible members of the cluster,
that lack either accurate spectral types or clear evidence of
membership, and that are optically visible (I≲18). I have used these
spectroscopic data and all other available constraints to evaluate the
spectral classifications and membership status of a total sample of
288 candidate members of Chamaeleon I that have appeared in published
studies of the cluster. The latest census of Chamaeleon I now contains
158 members, eight of which are later than M6 and thus are likely to
be brown dwarfs. I find that many of the objects identified as members
of Chamaeleon I in recent surveys are actually field stars. Meanwhile,
seven of nine candidates discovered by Carpenter and coworkers are
confirmed as members, one of which is the coolest known member of
Chamaeleon I at a spectral type of M8 (∼0.03M☉). I have
estimated extinctions, luminosities, and effective temperatures for
the members and used these data to construct an H-R diagram for the
cluster. Chamaeleon I has a median age of ∼2Myr according to
evolutionary models and hence is similar in age to IC 348 and is
slightly older than Taurus (∼1Myr). The measurement of an initial
mass function for Chamaeleon I from this census is not possible
because of the disparate methods with which the known members were
originally selected and must await an unbiased, magnitude-limited
survey of the cluster.
Description:
Observations were performed with the Boller & Chivens spectrograph
(B&C) and the low-dispersion survey spectrograph (LDSS-2) on the
Magellan I and II 6.5m telescopes at Las Campanas Observatory.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 65 116 Hα for members of Chamaeleon I
table3.dat 24 15 Liλ6707 for members of Chamaeleon I
table4.dat 92 157 Astrometry and photometry for members of
Chamaeleon I
table5.dat 208 157 Derived properties for members of Chamaeleon I
table6.dat 116 13 Foreground stars
table7.dat 116 91 Background stars
table8.dat 85 25 Sources with uncertain membership status
refs.dat 69 45 References
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See also:
J/MNRAS/267/755 : Polarimetry in the Chamaeleon I Dark Cloud (McGregor+, 1994)
J/A+A/357/219 : ISOCAM observations in Cha I. (Persi+, 2000)
J/AJ/121/974 : JHK photometry in Cha I (Gomez+, 2001)
J/AJ/121/2673 : 3µm survey of the Chamaeleon I dark cloud (Kenyon+, 2001)
J/A+A/423/1029 : XMM-Newton obs, in Cha I South (Stelzer+, 2004)
J/AJ/124/1001 : JHKs photometry of Cha I variables (Carpenter, 2002)
J/ApJ/614/267 : Chandra sources in Cha I North (Feigelson+, 2004)
J/ApJS/173/104 : Stellar population in Chamaeleon I (Luhman, 2007)
J/A+A/461/669 : XMM observations of Cha I dark cloud (Robrade+, 2007)
J/ApJ/675/1375 : IRAC/MIPS photometry in Cha I (Luhman+, 2008)
J/ApJ/684/654 : Low-mass members of Chamaeleon I (Luhman+, 2008)
J/A+A/527/A145 : Chamaeleon I 870um sources (Belloche+, 2011)
J/A+A/551/A46 : Cha I & II members compiled photometry (Lopez Marti+, 2013)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- ID Source name
25 A1 --- l_EW Limit flag on EW
26- 30 F5.1 0.1nm EW Equivalent width of the Hα line
33- 36 F4.1 0.1nm e_EW ? rms uncertainty on EW
37 A1 --- l_Flux Limit flag on Flux
38- 44 F7.2 aW/m2 Flux ?=- Observed Hα line flux
(10-15erg/cm2/s)
46 A1 --- l_log(LHa/Lb) Limit flag on log(LHa/Lb)
47- 51 F5.2 [-] log(LHa/Lb) ?=- Hα to bolometric luminosity ratio
(typical error is ±0.1)
55- 65 A11 --- SpT Spectral type
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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- 8 A8 --- ID Source name
10- 13 F4.2 0.1nm EW Equivalent width of the Liλ6707 line
15- 18 F4.2 0.1nm e_EW rms uncertainty on EW
20- 24 A5 --- SpT Spectral type
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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- 22 A22 --- ID Source name
24- 25 A2 --- n_ID [ef ] Note(s) on source (1)
27- 28 I2 h RAh Right ascension (J2000) (2)
30- 31 I2 min RAm Right ascension (J2000) (2)
33- 37 F5.2 s RAs Right ascension (J2000) (2)
39 A1 --- DE- Declination sign (J2000) (2)
40- 41 I2 deg DEd Declination (J2000) (2)
43- 44 I2 arcmin DEm Declination (J2000) (2)
46- 49 F4.1 arcsec DEs Declination (J2000) (2)
51- 55 F5.2 mag Imag ?=- DENIS second release (II/252) I magnitude
57- 60 F4.2 mag J-H ?=- 2MASS J-H colour index (3)
62- 65 F4.2 mag H-Ks ?=- 2MASS H-Ks colour index
67- 71 F5.2 mag Ksmag ?=- 2MASS Ks magnitude
73- 77 F5.2 mag [6.7] ? Magnitude at 6.7um (4)
79- 82 F4.2 mag e_[6.7] ? rms uncertainty on [6.7]
84- 87 F4.2 mag [14.3] ? Magnitude at 14.3um (4)
89- 92 F4.2 mag e_[14.3] ? rms uncertainty on [14.3]
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Note (1): Note as follows:
e = Additional comments on this source are in the Appendix of the paper
f = Sources T3, T27, T31, T33, T39, T41, T45, T51, T54, CHXR 47, and
Cha Hα 2 are resolved as binaries with separations of
2.2", 0.8", 0.66", 2.4"-2.5", 1.1", 0.84", 0.79", 1.5"-1.9", 0.27", 1.2",
and 0.2", respectively (Reipurth and Zinnecker 1993A&A...278...81R 1993A&A...278...81R;
Ghez et al. 1997ApJ...481..378G 1997ApJ...481..378G; Neuhauser et al. 2002A&A...395..877N 2002A&A...395..877N).
Note (2): 2MASS Point Source Catalog, except for ISO 13, which is from
Carpenter et al. 2002, Cat. Cat. J/AJ/124/1001
Note (3): 2MASS Point Source Catalog, except for J for T3, which is from the
Second DENIS Release.
Note (4): From Persi et al., 2000A&A...357..219P 2000A&A...357..219P
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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- 22 A22 --- ID Source name
24- 70 A47 --- SpT/W(Ha) Spectral type /EW(Hα) value(s) (1)
72- 82 A11 --- r_SpT/W(Ha) Reference(s) for SpT/W(Ha), in refs.dat file
84- 88 A5 --- SpT Adopted spectral type
90-109 A20 --- Memb Membership evidences (G1)
111-188 A78 --- r_Memb Reference(s) for Membership evidence,
in refs.dat file
190-194 I5 K Teff ?=- Effective temperature (3)
196-199 F4.2 mag AJ ?=- Absorption in J band
201-208 F8.4 Lsun Lbol ?=- Bolometric luminosity
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Note (1): Both spectral types and W(Hα) are provided when taken from
previous studies. The measurements of Hα from this work are listed
separately in Table 2. The precision of the optical spectral types from this
work is ±0.5 and 0.25 subclass for K and M types, respectively, unless
noted otherwise.
Note (3): Temperature scale from Schmidt-Kaler 1982, in Landolt-Bornstein,
Group VI, Vol. 2, ed. K.-H. Hellwege (Berlin: Springer), 454 (≤M0) and
Luhman et al. 2003, Cat. J/ApJ/593/1093 (>M0).
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Byte-by-byte Description of file: table6.dat table7.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- ID Source name
16 A1 --- n_ID [d] d indicates additional comments on this
source in the Appendix
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 28 F5.2 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 40 F4.1 arcsec DEs Declination (J2000)
42- 63 A22 --- SpT Spectral type(s)
65- 72 A8 --- r_SpT References for SpT, in refs.dat file
74- 83 A10 --- Evid Foreground or Background evidence (G1)
85- 94 A10 --- r_Evid Reference for evidence, in refs.dat file
96-100 F5.2 mag Imag ?=- I magnitude from Second DENIS Release
102-105 F4.2 mag J-H 2MASS PSC J-H colour index
107-110 F4.2 mag H-Ks 2MASS PSC H-Ks colour index
112-116 F5.2 mag Ksmag 2MASS PSC Ks magnitude
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Source name
9 A1 --- n_ID [c] indicates additional comments on this
source in the Appendix
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 21 F5.2 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 33 F4.1 arcsec DEs Declination (J2000)
35 I1 --- r [1/2] Reference for position (1)
37- 45 A9 --- SpT Spectral type(s)
47- 51 A5 --- r_SpT References for SpT (1)
53- 63 A11 --- Status Status (Background?, Member?, or ?)
65- 69 F5.2 mag Imag ?=- I magnitude from Second DENIS Release
71- 74 F4.2 mag J-H ?=- 2MASS PSC J-H colour index
76- 79 F4.2 mag H-Ks ?=- 2MASS PSC H-Ks colour index
81- 85 F5.2 mag Ksmag ?=- 2MASS PSC Ks magnitude
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Note (1): References as follows:
1 = Carpenter et al., 2002, Cat. J/AJ/124/1001
2 = 2MASS Point Source Catalog, Cat. II/246
3 = Gomez and Mardones, 2003AJ....125.2134G 2003AJ....125.2134G
4 = this paper
5 = Vrba and Rydgren, 1984ApJ...283..123V 1984ApJ...283..123V
6 = Feigelson and Kriss, 1989ApJ...338..262F 1989ApJ...338..262F
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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 Reference number
4- 22 A19 --- BibCode BibCode
24- 48 A25 --- Aut Author's name
52- 69 A18 --- Com Comments
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Global Notes:
Note (G1): Membership in Chamaeleon I is indicated by:
AV = AV≳1 and a position above the main sequence for the distance of
Chamaeleon I (AV<1 indicates a foreground field star)
e = strong emission lines
Na K = Na I and K I strengths intermediate between those of dwarfs and
giants
Li = strong Li absorption (weak absorption indicates a foreground star)
ex = IR excess emission
mu = proper motion indicates membership
pi = a parallax indicates membership
rv = radial velocity indicates membership
sp = spectral classification (dwarf indicates a foreground star)
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History:
* 13-Feb-2014: From electronic version of the journal
* 27-Jun-2014: 4 names corrected by CDS:
CHXR 33 into CHX 13a, CHXR 60 into CHXX 60,
Ced 110 IRS 4 into [PMG2001] NIR 76, CHXR 54 into CHX 21a
CHX 21B into HJM E 3-6 and GK 53 into GK 54.
(End) Patricia Vannier [CDS] 10-Oct-2013