J/ApJ/818/59 IN-SYNC. IV. YSOs in Orion A (Da Rio+, 2016)
IN-SYNC. IV. The young stellar population in the Orion A molecular cloud.
Da Rio N., Tan J.C., Covey K.R., Cottaar M., Foster J.B., Cullen N.C.,
Tobin J.J., Kim J.S., Meyer M.R., Nidever D.L., Stassun K.G.,
Chojnowski S.D., Flaherty K.M., Majewski S., Skrutskie M.F., Zasowski G.,
Pan K.
<Astrophys. J., 818, 59 (2016)>
=2016ApJ...818...59D 2016ApJ...818...59D (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Effective temperatures ; Photometry, infrared ;
YSOs ; Spectra, infrared
Keywords: open clusters and associations: individual: (Orion Nebula Cluster,
L1641); stars: formation; stars: kinematics and dynamics;
stars: pre-main sequence
Abstract:
We present the results of the Sloan Digital Sky Survey APOGEE INfrared
Spectroscopy of Young Nebulous Clusters program (IN-SYNC) survey of
the Orion A molecular cloud. This survey obtained high-resolution
near-infrared spectroscopy of about 2700 young pre-main-sequence stars
on a ∼6° field of view. We have measured accurate stellar
parameters (Teff, logg, vsini) and extinctions and placed the
sources in the Hertzsprung-Russel diagram (HRD). We have also
extracted radial velocities for the kinematic characterization of the
population. We compare our measurements with literature results to
assess the performance and accuracy of the survey. Source extinction
shows evidence for dust grains that are larger than those in the
diffuse interstellar medium: we estimate an average RV=5.5 in the
region. Importantly, we find a clear correlation between HRD inferred
ages and spectroscopic surface-gravity-inferred ages and between
extinction and disk presence; this strongly suggests a real spread of
ages larger than a few Myr. Focusing on the young population around
NGC 1980/ι Ori, which has previously been suggested to be a
separate, foreground, older cluster, we confirm its older (∼5Myr) age
and low AV, but considering that its radial velocity distribution is
indistinguishable from Orion A's population, we suggest that NGC 1980
is part of Orion A's star formation activity. Based on their stellar
parameters and kinematic properties, we identify 383 new candidate
members of Orion A, most of which are diskless sources in areas of the
region poorly studied by previous works.
Description:
Observations were carried out in 2013 December and 2014 January, with
the APOGEE spectrograph on the Sloan 2.5m telescope. APOGEE is a
fiber-fed multiobject infrared spectrograph, operating in H band in
the range 1.5µm≲λ≲1.6µm, capable of obtaining spectra
of up to 320 sources simultaneously on a corrected FOV of ∼7 square
degrees, and with a resolution R∼22500. Fifteen APOGEE plates, on five
positions in the sky, have been designed to cover the Orion A region
as shown in Figure 1. See section 2 for further explanations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 115 2691 Fitted stellar parameters
table5.dat 44 2691 Additional quantities
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See also:
J/ApJ/807/27 : IN-SYNC. III. RVs of IC348 stars (Cottaar+, 2015)
J/ApJ/799/136 : IN-SYNC. II. Candidate young stars in NGC 1333 (Foster+, 2015)
J/ApJ/794/125 : IN-SYNC. I. APOGEE stellar parameters (Cottaar+, 2014)
J/A+A/566/A45 : Orion optical-depth and column-density maps (Lombardi+, 2014)
J/ApJ/786/29 : Catalog of distances to molecular clouds (Schlafly+, 2014)
J/A+A/564/A29 : Optical and near-infrared photometry in Orion A (Bouy+, 2014)
J/AJ/146/85 : Spectral types of optical stars in ONC (Hillenbrand+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/ApJS/207/5 : YSOs in LDN 1641 with Hectochelle spectra (Fang+, 2013)
J/ApJ/769/149 : IR spectroscopy in Orion A: transitional disks (Kim+, 2013)
J/ApJ/768/99 : X-ray survey of YSOs in Orion A (Pillitteri+, 2013)
J/ApJ/767/36 : APEX observations of HOPS protostars (Stutz+, 2013)
J/ApJ/764/114 : BVRI photometry of stars in Orion A (Hsu+, 2013)
J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)
J/ApJ/752/59 : Low-mass population in L1641 (Hsu+, 2012)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/AJ/139/950 : JHKs photometry in ONC (Robberto+, 2010)
J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009)
J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)
J/ApJ/677/401 : Xray properties of protostars in ONC (Prisinzano+, 2008)
J/ApJ/676/1109 : Star velocities in the Orion Nebula Cluster (Furesz+, 2008)
J/ApJS/160/353 : Membership of the Orion nebula population (Getman+, 2005)
J/AJ/129/363 : Spectroscopy in Orion Nebula Cluster (Sicilia-Aguilar+, 2005)
J/AJ/128/787 : Chandra Orion flanking fields data (Ramirez+, 2004)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
http://www.sdss3.org/ : SDSS-III home page
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 1 I1 h RAh [5] Hour of Right Ascension (J2000)
3- 4 I2 min RAm [32/43] Minute of Right Ascension (J2000)
6- 10 F5.2 s RAs Second of Right Ascension (J2000)
12- 12 A1 --- DE- [-] Sign of the Declination (J2000)
13- 13 I1 deg DEd [4/9] Degree of Declination (J2000)
15- 16 I2 arcmin DEm Arcminute of Declination (J2000)
18- 22 F5.2 arcsec DEs Arcsecond of Declination (J2000)
24- 25 I2 --- Epoch [1/18] Epoch number of the observation
27- 34 F8.3 K Teff [2850/7001] Fitted effective temperature
36- 43 F8.3 K e_Teff [0.1/6079] Uncertainty in Teff
45- 50 F6.3 [cm/s2] log(g) [-0.5/5.5] Fitted log surface gravity
52- 56 F5.3 [cm/s2] e_log(g) [0.001/7.2] Uncertainty in log(g)
58- 65 F8.3 km/s vsin(i) [0.01/2387] Fitted projected rotational
velocity
67- 74 F8.3 km/s e_vsin(i) [0.04/2509] Uncertainty in vsin(i)
76- 81 F6.3 mag Jmag [6.1/15.8] The 2MASS J band magnitude
83- 87 F5.3 mag e_Jmag [0/10] Uncertainty in Jmag
89- 94 F6.3 mag Hmag [6.2/12.5] The 2MASS H band magnitude
96-100 F5.3 mag e_Hmag [0.01/0.5] Uncertainty in Hmag
102-108 F7.3 mag Av [-15.7/27.9] The V band extinction (1)
110-115 F6.3 mag e_Av [0.2/82.5] Uncertainty in Av
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Note (1): We derived the extinction of our IN-SYNC targets from the knowledge of
Teff and the observed colors. Specifically, we compared the sources'
observed (J-H) colors with the intrinsic ones from the 2.5Myr old
semiempirical isochrone from Bell et al. (2014MNRAS.445.3496B 2014MNRAS.445.3496B),
obtained applying an empirical correction to the PISA models
(Tognelli et al. 2012A&A...548A..41T 2012A&A...548A..41T) as converted into magnitudes
assuming BT-Settl (Allard et al. 2011ASPC..448...91A 2011ASPC..448...91A) synthetic
spectra. To convert the reddening excess E(J-H) to AV, we assumed
the reddening curve from Cardelli et al. (1989ApJ...345..245C 1989ApJ...345..245C) for a
reddening parameter RV=3.1 or 5.5. See section 3.2.
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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- 6 F6.3 [Lsun] logL [-3.3/2.2] Log luminosity
8- 12 F5.3 [Lsun] e_logL [0.03/8.1] Uncertainty in logL
14- 18 F5.3 [yr] logA [5/8.2]? Log age
20- 24 F5.3 [yr] e_logA [0/1.9]? Uncertainty in logA
26- 30 F5.3 Msun Mass [0.1/5.1]? Mass
32- 36 F5.3 Msun e_Mass [0/3]? Uncertainty in Mass
38 I1 --- OMm [0/1] Literature membership
from optical spectra (0=No, 1=Yes) (1)
40 I1 --- IRMm [0/1] Literature membership from IR excess (1)
42 I1 --- XMm [0/1] Literature membership from X-ray (1)
44 I1 --- nMm [0/1] New candidate member (0=No, 1=Yes) (1)
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Note (1): References for optical spectroscopy:
Hillenbrand 1997, J/AJ/113/1733 (<[H97b] NNNNa> in Simbad);
Da Rio et al. 2012, J/ApJ/748/14 (<[DRH2012] NNNN> in Simbad);
Hsu et al. 2012, J/ApJ/752/59 (<[HHA2012] NNN> in Simbad);
Hsu et al. 2013, J/ApJ/764/114;
Fang et al. 2009, J/A+A/504/461 (<[FVW2009] LNNNNA NNN> in Simbad);
Fang et al. 2013, J/ApJS/207/5 (<[FKV2013] NNNN> in Simbad);
IR excess:
Getman et al. 2005, J/ApJS/160/353 ( in Simbad);
Pillitteri et al. 2013, J/ApJ/768/99 ( in Simbad); and
X-ray:
Megeath et al. 2012, J/AJ/144/192 (<[MGM2012] NNNN> in Simbad)
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History:
From electronic version of the journal
References:
Cottaar et al. Paper I. 2014ApJ...794..125C 2014ApJ...794..125C Cat. J/ApJ/794/125
Foster et al. Paper II. 2015ApJ...799..136F 2015ApJ...799..136F Cat. J/ApJ/799/136
Cottaar et al. Paper III. 2015ApJ...807...27C 2015ApJ...807...27C Cat. J/ApJ/807/27
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Apr-2016