J/ApJ/782/8 Spectroscopy of 104 objects in the ONC (Ingraham+, 2014)
Near-infrared (JHK) spectroscopy of young stellar and substellar objects in
Orion.
Ingraham P., Albert L., Doyon R., Artigau E.
<Astrophys. J., 782, 8 (2014)>
=2014ApJ...782....8I 2014ApJ...782....8I (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, dwarfs ; Spectral types ;
Effective temperatures ; Extinction ; Stars, masses
Keywords: brown dwarfs - infrared: stars -
open clusters and associations: individual: Orion Nebular Cluster -
stars: formation - stars: low-mass -
stars: luminosity function, mass function
Abstract:
We performed low-resolution (R∼40) near-infrared (0.9-2.4µm)
multi-object spectroscopy of 240 isolated point sources having
apparent H-band magnitudes between 9 and 18 in the central 5'x6' of
the Orion Trapezium cluster. The observations were performed over four
nights at the Canada-France-Hawaii Telescope using the visiting
instrument SIMON, an infrared imager and multi-object spectrograph. We
present the spectra of 104 objects with accurately derived spectral
types including 7 new objects having masses below the hydrogen-burning
limit, and 6 objects with masses below the deuterium-burning limit.
The spectral classification is performed by fitting previously
classified spectral templates of dwarf stars (K4-M3) and optically
classified young stellar and substellar objects (M4-L0), to the entire
0.9-2.4µm spectral energy distribution in order to assign a
spectral type and visual extinction for each object. Of the 104
objects studied, 44 have been previously classified spectroscopically
using various techniques. We perform a rigorous comparison between the
previous classifications and our own and find them to be in good
agreement. Using the dereddened H-band magnitudes, the classified
objects are used to create an Hertzsprung-Russell diagram for the
cluster. We find that the previous age estimates of ∼1Myr to be
consistent with our results. Consistent with previous studies,
numerous objects are observed to have luminosities several magnitudes
above the 1Myr isochrone. Numerous objects exhibiting emission
features in the J band are also reported.
Description:
In 2003 December, we obtained six nights (on CFHT to perform MOS
observations of faint objects in the central region of the Orion
Trapezium cluster. The observations used the infrared imager and
multi-object spectrograph SIMON (Spectrometre Infrarouge de Montreal).
The optical design is fully achromatic between 0.8 and 2.5µm and
features a HAWAII-I 1024*1024 HgCdTe detector with an image scale of
0.2'' on CFHT. SIMON utilizes a low-dispersion Amici prism enabling
multi-object low-resolution (R∼30) spectroscopy over the wavelength
range of 0.9-2.4µm.
The slit width, in the spectral direction, was chosen to be 0.6''
(3pixels) resulting in a spectral resolution of R∼30. In total,
spectra for 240 point sources were obtained. Here, we present only the
104 objects (see Table5) with low-extinction (AV<8) spectra having
well constrained spectral types.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 148 56 Previously classified objects
table5.dat 170 104 Properties of observed sources
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See also:
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/A+A/534/A10 : HST/NICMOS III imaging in ONC (Andersen+, 2011)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)
J/AJ/134/2272 : Visual binaries in the Orion Nebula Cluster (Reipurth+, 2007)
J/A+A/458/461 : Binary stars in the Orion Nebula Cluster (Koehler+, 2006)
J/MNRAS/361/211 : JHK photometry of brown dwarfs in Orion (Lucas+, 2005)
J/ApJ/540/236 : KH photometry of Orion Nebula Cluster (Hillenbrand+, 2000)
J/AJ/117/1375 : Orion Trapezium cluster (Simon+, 1999)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/AJ/111/846 : Orion HST survey (O'Dell+ 1996)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Hour of Right Ascension (J2000) (G1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (G1)
7- 11 F5.2 s RAs Second of Right Ascension (J2000) (G1)
13 A1 --- DE- Sign of the Declination (J2000) (G1)
14- 15 I2 deg DEd Degree of Declination (J2000) (G1)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000) (G1)
25- 33 A9 --- Name Identifier from this work (G2)
35 I1 --- Ref Reference (2)
37- 43 A7 --- OName Other name (reference identifier)
45- 51 A7 --- SpTr Reference spectral type
53- 56 F4.2 --- e_SpTr ? Uncertainty in SpTr
58- 62 A5 --- SpT Spectral type from this work
64- 68 A5 --- SpT1 Later range in SpT
70- 74 A5 --- SpT0 Early range in SpT
76- 80 F5.2 mag AVr [0/10.5]? Reference V band extinction
82 A1 --- f_AVr Reddening/dereddening flag on AVr (c or d) (3)
84- 86 F3.1 mag AV [0/7.5] V band extinction from this work
88- 90 F3.1 mag e_AV [0/5.9] Lower limit on AV
92- 94 F3.1 mag E_AV [0/8.4] Upper limit on AV
96-148 A53 --- Summary Comparison summary
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Note (2): Reference codes are defined as below:
1 = Weights et al (2009MNRAS.392..817W 2009MNRAS.392..817W);
2 = Slesnick et al (2004ApJ...610.1045S 2004ApJ...610.1045S) and reference therein;
3 = Riddick et al (2007MNRAS.381.1077R 2007MNRAS.381.1077R).
Note (3): The flags are defined as below:
c = Reddening derived assuming an age of 1Myr. Uses reddening law of
Cohen et al. (1981ApJ...249..481C 1981ApJ...249..481C);
d = Derived by dereddening photometric J and H colors to the 1Myr isocrone.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Hour of Right Ascension (J2000) (G1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (G1)
7- 11 F5.2 s RAs Second of Right Ascension (J2000) (G1)
13 A1 --- DE- Sign of the Declination (J2000) (G1)
14- 15 I2 deg DEd Degree of Declination (J2000) (G1)
17- 18 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000) (G1)
25- 33 A9 --- Name Identifier (G2)
35 I1 --- Field [1/7] Field number (1, 6, or 7)
37- 40 F4.1 mag Hmag [9.1/17.8] H band magnitude
42 A1 --- r_Hmag Reference or uncertainty flag on Hmag (1)
44- 47 F4.1 mag H0mag [8.4/17.8] Dereddened H band magnitude
49- 53 A5 --- SpT Spectral type
55- 59 A5 --- SpT1 Later range in SpT
61- 65 A5 --- SpT0 Early range in SpT
67- 70 F4.1 mag AV [0/10.2] The V band extinction
72- 75 F4.1 mag e_AV [0/10.7] Lower limit on AV
77- 80 F4.1 mag E_AV [0/10.5] Upper limit on AV
82- 85 I4 K Teff [2000/4340] Effective temperature
87- 90 I4 K e_Teff [2000/3680] Lower limit on Teff
92- 95 I4 K E_Teff [2350/5240] Upper limit on Teff
97 A1 --- l_Mass [>] Lower limit flag on Mass
99-103 F5.3 Msun Mass [0.006/1.4]? Mass
105-109 F5.3 Msun e_Mass [0.006/0.814]? Lower limit on Mass
111 A1 --- n_Mass [>] Indicates E_Mass is a lower limit
113-117 F5.3 Msun E_Mass [0.012/1.4]? Upper limit on Mass
119-170 A52 --- Note Additional notes
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Note (1): The flags are defined as below:
b = Magnitude value from 2MASS Point Source Catalog (cat. II/246);
c = Magnitude value from 2MASS Point Source Reject Catalog;
d = Magnitude value from Lucas et al. 2005 (cat. J/MNRAS/361/211);
e = Uncertain.
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Global Notes:
Note (G1): Position added at CDS from Name designation.
Note (G2): Name format follows from O'Dell & Wong 1996 (cat. J/AJ/111/846).
XXXX-YYYY implies an RA of 05:35:XX.XX and DEC of -05:2Y:YY.Y
History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 17-Mar-2016