J/ApJ/794/36 σ Orionis cluster stellar population (Hernandez+, 2014)
A spectroscopic census in young stellar regions: the σ Orionis cluster.
Hernandez J., Calvet N., Perez A., Briceno C., Olguin L., Contreras M.E.,
Hartmann L., Allen L., Espaillat C., Hernan R.
<Astrophys. J., 794, 36 (2014)>
=2014ApJ...794...36H 2014ApJ...794...36H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Photometry, infrared ;
Spectral types ; Equivalent widths ; Extinction ;
Radial velocities ; Stars, distances
Keywords: infrared: stars -
open clusters and associations: individual: σ Orionis cluster -
protoplanetary disks - stars: formation - stars: pre-main sequence
Abstract:
We present a spectroscopic survey of the stellar population of the
σ Orionis cluster. We have obtained spectral types for 340 stars.
Spectroscopic data for spectral typing come from several spectrographs
with similar spectroscopic coverage and resolution. More than half of
the stars in our sample are members confirmed by the presence of
lithium in absorption, strong Hα in emission or weak
gravity-sensitive features. In addition, we have obtained
high-resolution (R∼34000) spectra in the Hα region for 169 stars
in the region. Radial velocities were calculated from this data set.
The radial velocity distribution for members of the cluster is in
agreement with previous work. Analysis of the profile of the Hα
line and infrared observations reveals two binary systems or fast
rotators that mimic the Hα width expected in stars with
accretion disks. On the other hand, there are stars with optically
thick disks and narrow Hα profiles not expected in stars with
accretion disks. This contribution constitutes the largest homogeneous
spectroscopic data set of the σ Orionis cluster to date.
Description:
We obtained optical photometry (UBVRCIC) of the center of the cluster
on 2011 December 24 using the Ohio State Multi-Object Spectrograph
(OSMOS) on the MDM 2.4 m Hiltner telescope (Stoll et al.
2010SPIE.7735E..4LS; Martini et al. 2011PASP..123..187M 2011PASP..123..187M). We obtained
two sets of images, one short exposure set (20, 15, 10, 5, and 5 s for
U, B, V, RC and IC, respectively) and one long exposures set
(3x200, 3x200, 3x150, 3x100, and 3x100 s for U, B, V, RC, and
IC, respectively). The initial sample in this study includes all Two
Micron All Sky Survey (2MASS) sources (4659 sources; Cutri et al.
2003yCat.2246....0C 2003yCat.2246....0C) in a region of 48'x48' centered at RA=84.7°
and DE=-2.6°. This region covers the field studied in H07b
(Hernandez et al. 2007, J/ApJ/662/1067) using the four channels of the
InfraRed Array Camera (IRAC; Fazio et al. 2004ApJS..154...39F 2004ApJS..154...39F). The
2MASS catalog (Cutri et al. 2003yCat.2246....0C 2003yCat.2246....0C, Cat.II/246) is
complete down to J<15.8, which includes stars beyond the substellar
limit expected for the σ Orionis cluster (e.g., J∼14.6;
Hernandez et al. 2007, J/ApJ/662/1067).
Objects:
------------------------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------------------------
05 38 42 -02 36.0 σ Orionis cluster = C 0536-026
------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 82 297 Compiled membership information of
the σ Orionis cluster
table2.dat 119 728 Photometric candidates
table4.dat 86 340 Low resolution analysis
table5.dat 111 142 High resolution analysis
table6.dat 125 340 Membership for stars with spectral types
table7.dat 79 25 Membership for Stars without Spectral Types
Studied in Section 3.2
table9.dat 122 125 Known members compiled in section 2.3 and new
disk bearing candidates not listed in Table 6
and Table 7
table10.dat 60 59 Additional photometric candidates not listed
in Table 6, Table 7 and Table 9
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/41 : XMM-Newton Serendipitous Source Catalogue 2XMMi-DR3
(XMM-SSC, 2010)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
J/A+A/419/249 : RJHKs photometry of sigma Ori low-mass stars (Scholz+, 2004)
J/AJ/128/2316 : BVRIJHKs photometry in sigma Ori cluster (Sherry+, 2004)
J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005)
J/MNRAS/356/89 : sigma Ori low-mass stars (Kenyon+, 2005)
J/MNRAS/356/1583 : RV of Sigma Ori low-mass candidate members
(Burningham+, 2005)
J/A+A/466/917 : Brightest stars of sigma Orionis cluster (Caballero+, 2007)
J/ApJ/662/1067 : Spitzer observations of sigma Orionis (Hernandez+, 2007)
J/MNRAS/375/1220 : BVI photometry of young stars in 10 clusters (Mayne+, 2007)
J/A+A/478/667 : The Mayrit catalogue (Caballero, 2008)
J/A+A/488/167 : Low-mass stars in σ Ori and λ Ori
(Sacco+, 2008)
J/A+A/521/A45 : X-ray detections in the σ Ori cluster
(Caballero+, 2010)
J/ApJS/191/389 : Photometric monitoring in σ Ori cluster (Cody+, 2010)
J/ApJ/754/30 : VISTA IR photometry of σ Ori cluster
(Pena Ramirez+, 2012)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8 A1 --- f_Name Flag on Name (1)
10- 25 A16 --- 2MASS 2MASS identifier
27- 35 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
37- 45 F9.6 deg DEdeg Declination in decimal degrees (J2000)
47- 49 A3 --- Disk Disk type (G1)
51- 59 A9 --- LiI Li I reference(s) (G2)
61- 67 A7 --- RV Radial velocity reference(s) (G2)
69- 82 A14 --- X-ray X-ray observation reference(s) (G2)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
1 = Strong Hα line and Accretion disk (Scholz & Eisloffel 2004,
J/A+A/419/249; Scholz et al. 2009MNRAS.398..873S 2009MNRAS.398..873S);
2 = Strong Hα line and Accretion disk (Caballero 2008, J/A+A/478/667).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
26 A1 --- f_2MASS [3] Flag on 2MASS (1)
28- 35 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
37- 44 F8.5 deg DEdeg Declination in decimal degrees (J2000)
46- 50 F5.2 mag Umag ? The U band magnitude
52- 55 F4.2 mag e_Umag ? Uncertainty in U mag
57- 61 F5.2 mag Bmag ? The B band magnitude
63- 66 F4.2 mag e_Bmag ? Uncertainty in B mag
68- 72 F5.2 mag Vmag The V band magnitude
74- 77 F4.2 mag e_Vmag Uncertainty in V mag
79- 83 F5.2 mag Rmag ? The R band magnitude
85- 88 F4.2 mag e_Rmag ? Uncertainty in R mag
90- 94 F5.2 mag Imag ? The I band magnitude
96- 99 F4.2 mag e_Imag ? Uncertainty in I mag
101-105 F5.2 mag Jmag 2MASS J band magnitude
107-110 F4.2 mag e_Jmag Uncertainty in J mag
112 A1 --- f_Jmag [1] Flag on Jmag (2)
114-117 A4 --- Ref Reference code (3)
119 A1 --- f_Ref [2] Flag on Ref (4)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
3 = Sources labeled as galaxies by Lawrence et al.
(2013yCat.2319....0L 2013yCat.2319....0L, Cat. II/319).
Note (2): Flag as follows:
1 = J magnitude from UKIDSS (2007MNRAS.379.1599L 2007MNRAS.379.1599L, Cat. II/314 ;
2013yCat.2319....0L 2013yCat.2319....0L, Cat. II/319).
Note (3): Code as follows:
OS = OSMOS (Section 2.1.1);
CVSO = CIDA Variability Survey of Orion (Briceno et al. 2005, J/AJ/129/907);
S04 = Sherry et al. (2004, J/AJ/128/2316);
CLC = Cluster Collaboration (Kenyon et al. 2005, J/MNRAS/356/89;
Mayne et al. 2007, J/MNRAS/375/1220);
K09 = Kharchenko & Roeser (2009yCat.1280....0K 2009yCat.1280....0K).
Note (4): Flag as follows:
2 = Known members not selected as photometric candidates.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8 A1 --- f_Name [2/3] Flag on Name (1)
10- 25 A16 --- 2MASS 2MASS identifier
28- 33 A6 --- Inst Instrument used (2)
35 A1 --- f_Inst [1] Flag on Inst (3)
37- 40 A4 --- SpType Numerical spectral Type
42- 44 F3.1 --- e_SpType Uncertainty in SpType
46- 48 F3.1 0.1nm EWLiI Li I equivalent width; in Angstroms
50 I1 --- f_EWLiI [0/2] Flag on EWLiI (G3)
52- 57 F6.1 0.1nm EWHa ? Hα equivalent width; in Angstroms
59- 64 A6 --- f_EWHa Flag on Ha (5)
66- 69 F4.2 0.1nm EWNaI ? Na I equivalent width; in Angstroms
71- 74 F4.2 0.1nm e_EWNaI ? Uncertainty in EWNaI
76 A1 --- f_EWNaI [YN] Flag on EWNaI (6)
78- 81 F4.2 mag AVKH95 ? Kenyon & Hartmann 1995 (J/ApJS/101/117)
V band extinction
83- 86 F4.2 mag AVPM13 ? Pecaut & Mamajek 2013 (J/ApJS/208/9)
V band extinction
--------------------------------------------------------------------------------
Note (1): Flag as follows:
2 = Slow accretor candidate;
3 = Diskless stars that mimic the Hα width expected in stars with
accretion disks.
Note (2): See text and Table 3.
Note (3): Flag as follows:
1 = Low signal to noise (S/N~<15)
Note (5): Flag as follows:
Acr = accretor;
nAcr = non-accretor;
Acr? = uncertain;
Eabs = star earlier than G5 with Hα in absorption;
ETem = star earlier than G5 with Hα in emission.
Note (6): Flag as follows:
Y = member;
N = non-member.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
25- 29 F5.1 km/s RVel ? Radial velocity
31- 33 F3.1 km/s e_RVel ? Uncertainty in RVel
35 I1 --- f_RVel [0/2]? Flag on RVel (G4)
37- 40 F4.2 0.1nm EWLiI ? Li I equivalent width; in Angstroms
42- 45 F4.2 0.1nm e_EWLiI ? Uncertainty in EWLiI
47- 53 F7.3 km/s W10Ha ? Hα Full width at 10% line peak
55 A1 --- Acretor [YN] Acretor flag (2)
57- 59 A3 --- Disk Disk type (G1)
61-111 A51 --- Com Additional comment(s) (4)
--------------------------------------------------------------------------------
Note (2): Flag as follows:
Y = accretor (W10Hα>270 km/s);
N = non-accretor (W10Hα<270 km/s).
Note (4): Comment as follows:
RVVAR = binary candidate by radial velocity variability;
SB2 = binary candidate identified in the cross correlation function.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
26- 29 A4 --- SpType Numerical spectral type
31- 33 F3.1 --- e_SpType Uncertainty in SpType
35 I1 --- LiIl [0/2] Li I flag from low resolution spectra
(G3)
37 I1 --- LiIh [0/2]? Li I flag from high resolution
spectra (G3)
39- 47 A9 --- r_LiIh Reference code(s) for LiIh (G2)
49 A1 --- RVel [0-2] Radial velocity flag (G4)
51- 57 A7 --- r_RVel Reference code(s) for RVel (G2)
59- 65 A7 --- Ha Hα from low/high spectra (1)
67 A1 --- NaI [YN] Na I present?
69- 71 A3 --- Disk Disk type (G1)
73- 86 A14 --- X-ray X-ray reference(s) (G2)
88 A1 --- PM [0-2] Proper motion flag (G5)
90 A1 --- Dist [0-1] Distance flag (G6)
92-102 A11 --- Var Variability reference(s) (G2)
104-107 F4.1 % Pmemb ? Photometric membership probability
109-113 F5.2 mag AV ? V band extinction
115-125 A11 --- Member Member flag (G8)
--------------------------------------------------------------------------------
Note (1): Flag as follows:
Acr = accretor;
nAcr = non-accretor;
Acr? = uncertain;
Eabs = star earlier than G5 with Hα in absorption;
ETem = star earlier than G5 with Hα in emission.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
25 I1 --- LiI [0/2] Li I flag (G3)
27- 29 A3 --- r_LiI Li I reference(s) (G2)
31 A1 --- RVel [0-2] Radial velocity flag (G4)
33- 36 A4 --- r_RVel RVel reference(s) (1) (G2)
38 A1 --- Halpha [YN-] Hα flag
40- 42 A3 --- Disk Disk type (G1)
44- 54 A11 --- X-ray X-ray reference(s) (1) (G2)
56 A1 --- PM [1-2] Proper motion flag (G5)
59 A1 --- Dist [0-1] Distance flag (G6)
61- 71 A11 --- Var Variability reference(s) (G2)
73- 76 F4.1 % Pmemb Photometry membership probability
78- 79 A2 --- Member [MNPU:] Member flag (G8)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
25- 30 F6.3 mag Vmag ? V band magnitude
32- 36 A5 --- Disk Disk type (G1)
38- 42 A5 --- LiI Li I reference (G2)
44- 50 A7 --- RV Radial velocity reference (G2)
52- 65 A14 --- X-ray X-ray reference (G2)
67 A1 --- PM [0-2] Proper motion flag (G5)
69 A1 --- Dist [0/1] Distance flag (G6)
71- 81 A11 --- Var Variability flag (G2)
83- 87 F5.1 % Pho Photometric membership probability
89-107 A19 --- SpType Spectral type
109-120 A12 --- r_SpType Reference for SpType (G2)
122 A1 --- Notes Additional note (G7)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Hernandez et al. (2007, J/ApJ/662/1067)
source identifier (SONNNN, [HHM2007] NNNN
in Simbad)
8- 23 A16 --- 2MASS 2MASS identifier
25- 30 F6.3 mag Vmag ? The V band magnitude
32 A1 --- PM [0-2] Proper motion flag (G5)
34 A1 --- Dist [0/1] Distance flag (G6)
36- 43 A8 --- Var Variability reference(s) (G2)
45- 48 F4.1 % Pmemb ? Photometric membership probability
50- 53 A4 --- SpType Spectral type
55- 58 A4 --- r_SpType Reference(s) for SpType (G2)
60 A1 --- f_SpType Flag on SpType (G7)
--------------------------------------------------------------------------------
Global notes:
Note (G1): Type as follows:
III = diskless;
II = thick disk;
I = class I;
EV = evolved disk;
TD = transition disk;
DD = Debris disk.
Note (G2): References as follows:
1 = Wolk (1996, PhD thesis, State Univ. New York at Stony Brook);
2 = Zapatero Osorio et al. (2002A&A...384..937Z 2002A&A...384..937Z);
3 = Barrado y Navascues et al. (2003A&A...404..171B 2003A&A...404..171B);
4 = Andrews et al. (2004ApJ...606..353A 2004ApJ...606..353A);
5 = Kenyon et al. (2005, J/MNRAS/356/89);
6 = Caballero (2006A&A...460..635C 2006A&A...460..635C);
7 = Gonzalez Hernandez et al. (2008A&A...490.1135G 2008A&A...490.1135G);
8 = Sacco et al. (2008, J/A+A/488/167);
9 = Caballero et al. (2012A&A...546A..59C 2012A&A...546A..59C);
10 = Alcala et al. (1996A&AS..119....7A 1996A&AS..119....7A);
11 = Caballero et al. (2006, PhD thesis, Universidad de La Laguna);
12 = Muzerolle et al. (2003ApJ...592..266M 2003ApJ...592..266M);
13 = Maxted et al. (2008, J/MNRAS/385/2210);
14 = Caballero (2008, J/A+A/478/667);
15 = Skinner et al. (2008ApJ...683..796S 2008ApJ...683..796S);
16 = Lopez-Santiago & Caballero (2008A&A...491..961L 2008A&A...491..961L);
17 = Caballero et al. (2009AJ....137.5012C 2009AJ....137.5012C);
18 = Caballero (2010, J/A+A/521/A45);
19 = XMMN-SSC (2010, Cat. IX/41);
20 = Burningham et al. (2005, J/MNRAS/356/1583);
21 = CVSO (Briceno et al. 2005, J/AJ/129/907);
22 = Cluster Collaboration (Kenyon et al. 2005, J/MNRAS/356/89;
Mayne et al. 2007, J/MNRAS/375/1220);
23 = Cody & Hillenbrand (2010, J/ApJS/191/389);
24 = AAVSO (Watson 2006JAVSO..35..318W 2006JAVSO..35..318W);
25 = Bejar et al. (1999ApJ...521..671B 1999ApJ...521..671B);
26 = Scholz & Eisloffel (2004, J/A+A/419/249);
27 = Cody & Hillenbrand (2011ApJ...741....9C 2011ApJ...741....9C);
28 = Rigliaco et al. (2012, J/A+A/548/A56);
29 = Oliveira et al. (2006MNRAS.369..272O 2006MNRAS.369..272O);
30 = Gatti et al. (2008A&A...481..423G 2008A&A...481..423G);
31 = Oliveira & van Loon (2004A&A...418..663O 2004A&A...418..663O);
32 = Sherry et al. (2008AJ....135.1616S 2008AJ....135.1616S);
33 = Houk & Swift (1999, Michigan Catalogue of Two-dimensional Spectral
Types for the HD Stars, Vol. 5 (Ann Arbor, MI: Department of Astronomy,
University of Michigan));
34 = Nesterov et al. (1995A&AS..110..367N 1995A&AS..110..367N).
Note (G3): Referenced as follows:
0 = Li I is not present on the spectrum;
1 = Li I uncertain;
2 = Li I is present in absoprtion.
Note (G4): Flag as follows:
0 = kinematic non-member;
1 = sparser stellar population candidate;
2 = kinematic member.
Note (G5): Flag as follows:
0 = greater than 5σ;
1 = between the 3σ and 5σ limit;
2 = inside the 3σ limit.
Note (G6): Flag as follows:
0 = further than 20' from center;
1 = closer than 20' from center.
Note (G7): Note as follows:
1 = Source labeled as galaxy by Lawrance et al. (2013yCat.2319....0L 2013yCat.2319....0L);
2 = Bright member of the cluster (Sherry et al. 2008AJ....135.1616S 2008AJ....135.1616S;
Caballero 2007, J/A+A/466/917);
3 = Photometric candidate (Lodieu et al. 2009A&A...505.1115L 2009A&A...505.1115L);
4 = New disk bearing candidate (Section 4.1).
Note (G8): Flag as follows:
M = member;
N = non-member;
P = probable member;
U = uncertain member;
1 = σ Ori AB:Multiple system;
2 = HD37699: probable disk detected using IRAS Caballero
(2007, J/A+A/466/917);
3 = HD37333: It is a member if is a equal mass binary
(Sherry et al. 2008AJ....135.1616S 2008AJ....135.1616S);
4 = HD37564: It is too bright to be a cluster member
(Sherry et al. 2008AJ....135.1616S 2008AJ....135.1616S);
5 = HD294273: It is too faint to be a cluster member (field star;
Sherry et al. 2008AJ....135.1616S 2008AJ....135.1616S);
6 = 04771-00621: It is inside of the 3σ proper motion limit
(Section 3.3.2), however Caballero (2007, J/A+A/466/917) reported that
this star has large proper motion to be a cluster member;
7 = Included as Foreground or Backgorund star in Caballero
(2008, J/A+A/478/667);
8 = Known member with relatively high proper motion;
9 = The Li 1 is lower than those expected for the σ Ori stellar
population (see Section 3.2);
10 = RV is consistent with the RV distribution of the cluster but Li I
was not detected;
11 = Variability amplitude in J band≳2.7;
12 = Star bearing an optically thick disk classified as non-accretor
following the criteria from Barrado y Navascues et al.
(2003A&A...404..171B 2003A&A...404..171B);
13 = Diskless star classified as accretor following the criteria
from Barrado y Navascues et al. (2003A&A...404..171B 2003A&A...404..171B);
14 = Binary candidate by RV variability;
15 = Binary candidate identified in the cross correlation function
(see Section 3.2);
16 = It has discrepant RV and Li 1 in absorption;
17 = Star bearing an optically thick disk classified as non-accretor
following the criteria from White & Basri (2003ApJ...582.1109W 2003ApJ...582.1109W);
18 = Diskless star that mimic the Hα width expected in star with
accretion disk; Fast rotator or Binary;
19 = Disk reported in this work;
20 = Source labeled as Galaxy by Lawrence et al. (2013yCat.2319....0L 2013yCat.2319....0L);
21 = Background source in Figure 1. Photometric member by
Lodieu et al. (2009A&A...505.1115L 2009A&A...505.1115L);
22 = An active background galaxy Caballero et al. (2010, J/A+A/521/A45);
23 = A foreground star Lopez-Santiago & Caballero (2008A&A...491..961L 2008A&A...491..961L);
24 = A foreground dwarf Caballero (2010A&A...514A..18C 2010A&A...514A..18C).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 24-Apr-2017