J/AJ/113/1733 Orion Nebula Cluster population (Hillenbrand 1997)
On the stellar population and star-forming history of the Orion Nebula Cluster
Hillenbrand L.A.
<Astron. J. 113, 1733 (1997)>
=1997AJ....113.1733H 1997AJ....113.1733H
ADC_Keywords: Populations, stellar ; Photometry, Cousins
Abstract:
We report on the first phase of a study of the stellar population
comprising the Orion Nebula Cluster (ONC). Approximately 50% of the
∼3500 stars identified to date within ∼2.5pc of the namesake Trapezium
stars are optically visible, and in this paper we focus on that sample
with I<2.5mag. The large number and number density of stars
(npeak>104pc-3), the wide range in the stellar mass
(∼0.1-50M☉), and the extreme youth (<1-2Myr) of the stellar
population, make the ONC the best site for investigating: (1) the
detailed shape of a truly "initial" mass spectrum; (2) the apparent
age spread in a region thought to have undergone triggered star
formation; (3) the time sequence of star formation as a function of
stellar mass; and (4) trends of all of the above with cluster radius.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 132 1576 Optical properties of ONC stars
table3.dat 42 1576 Derived properties of ONC stars
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See also:
II/171 : Parenago Catalog of Stars in Orion Nebula (Parenago 1954)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID Identification number (1)
5 A1 --- m_ID Multiplicity index on ID
7- 10 I4 --- Parenago ? Parenago (1954, Cat II/171) number (2)
12- 13 I2 % Mem ?=-9 Membership probability (3)
15- 16 I2 h RAh Right ascension (J2000) (4)
18- 19 I2 min RAm Right ascension (J2000)
21- 25 F5.2 s RAs Right ascension (J2000)
27 A1 --- DE- Declination sign
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 38 F5.2 arcsec DEs Declination (J2000)
40- 44 F5.2 min Rproj Projected radius from Theta 1C Ori
46- 50 F5.2 mag Imag ?=-9.99 Adopted I magnitude (Cousins)
52 A1 --- l_V-I Limit flag on V-I
(from Prosser et al., 1994ApJ...421..517P 1994ApJ...421..517P)
53- 57 F5.2 mag V-I ?=-9.99 Adopted V-I color index
59- 60 I2 --- Ref ? Photometry reference (5)
62- 64 A3 --- Comm ? Comment reference (6)
66- 71 F6.3 [K] logT ?=-9.999 Effective temperature of adopted
spectral type
73-132 A60 --- SpT Spectral type with reference in parentheses (7)
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Note (1): ID = adopted ``red'' identification number:
* 1-1053 from Jones & Walker, 1988AJ.....95.1755J 1988AJ.....95.1755J
* 1054-2999 from Parenago, 1954, Cat II/171
* 3000-3999 from this paper, 1993 January CCD data
* 5000-5999 from this paper, 1995 January CCD data
* 6000-6999 from this paper, 1996 January CCD data
* 9000-9999 from Prosser et al., 1994ApJ...421..517P 1994ApJ...421..517P
(number is 9000 plus original number from that paper)
Note (2): Par = Parenago or ``blue'' identification number
Note (3): Adopted membership probability taken from
Jones & Walker (1988AJ.....95.1755J 1988AJ.....95.1755J) with first priority, and
supplemented with van Altena et al. (1988AJ.....95.1744), McNamara
(1976AJ.....81..375M 1976AJ.....81..375M and 1976AJ.....81..845M 1976AJ.....81..845M), McNamara & Huels
(1983A&AS...54..221M 1983A&AS...54..221M), or McNamara et al. (1989AJ.....97.1427M 1989AJ.....97.1427M).
In addition, sources showing proper motion on my CCD frames were given
a membership probability of "0" while sources designated as "proplyds"
were given a membership probability of 99%; see "Comm" column.
Note (4): Equinox 2000. position, referenced to the HST Guide Star Catalog
(Cat. I/220; see text.
Note (5): Ref = photometry reference, as follows:
1 = this paper; 1993 January CCD data
2 = this paper; 1995 February CCD data
3 = this paper; 1996 February CCD data
4 = Prosser et al., 1994ApJ...421..517P 1994ApJ...421..517P
5 = Jones & Walker, 1988AJ.....95.1755J 1988AJ.....95.1755J
6 = McCullough et al., 1995ApJ...438..394M 1995ApJ...438..394M
7 = Breger, Gehrz, & Hackwell, 1981ApJ...248..963B 1981ApJ...248..963B
8 = Penston, 1973ApJ...183..505P 1973ApJ...183..505P or
Penston et al., 1975MNRAS.171..219P 1975MNRAS.171..219P
9 = Herbig & Terndrup, 1986ApJ...307..609H 1986ApJ...307..609H
10 = Herbst, 1993, priv. comm.
11 = Rydgren & Vrba, 1984AJ.....89..399R 1984AJ.....89..399R
Note (6): Comments uses the following numbers:
1 = externally ionized "proplyd"
2 = nebulous on 0.9m CCD images
3 = unresolved double on 0.9m CCD images
4 = >1.5 mag variability at I-band compared to Jones & Walker
(1988AJ.....95.1755J 1988AJ.....95.1755J) photographic photometry, or as designated by
Choi & Herbst (1996AJ....111..283C 1996AJ....111..283C) or by
Jones & Walker (1988AJ.....95.1755J 1988AJ.....95.1755J)
5 = alternate designation from Prosser et al. (1994ApJ...421..517P 1994ApJ...421..517P):
JW378a=9011, JW378b=9012, JW377a=9013, JW377b=9014,
JW399a=9034, JW399b=9033, JW435a=9057, JW435b=9058,
JW436a=9059, JW436b=9060, JW445b=9067, JW445a=9068,
JW472a=9099, JW472b=9098, JW484a=9111, JW484b=9112,
JW504b=9125, JW504a=9126, JW509a=9129, JW509b=9130,
JW511b=9134, JW511a=9136, JW519b=9143, JW519a=9144,
JW526b=9150, JW526a=9152, JW551b=9172, JW551a=9173,
JW552a=9183, JW552b=9184, JW553a=9185, JW553b=9186,
JW570a=9202, JW570b=9203, JW598b=9234, JW598a=9235,
JW648b=9262, JW648a=9263, JW687b=9286, JW687a=9288,
JW748b=9314, JW748a=9315, JW766b=9321, JW766a=9322,
JW776a=9323, JW776b=9324
6 = coordinates for JW618 given by Jones & Walker are incorrect;
source is NE of their position
7 = source has close companion in infrared images
8 = large proper motion on 0.9m CCD frames; assigned zero membership
probability
9 = resolved double on 0.9m CCD frames
Note (7): Spectral Type = all available spectral type information with
references in parentheses as listed below.
B = Blanco, 1963ApJ...137..513B 1963ApJ...137..513B
CK = Cohen & Kuhi, 1979ApJS...41..743C 1979ApJS...41..743C
D = Duncan, 1993ApJ...406..172D 1993ApJ...406..172D
Eetal = Edwards et al., 1993AJ....106..372E 1993AJ....106..372E
GS = Greenstein & Struve, 1946PASP...58..366G 1946PASP...58..366G
H = Hillenbrand, 1997 (this paper)
"e" indicates emission in the CaII triplet lines
"<" indicates spectral type is earlier than that listed
">" indicates spectral type is later than that listed
-- most spectra later than ∼M3 show indications of
surface gravity intermediate between that of dwarfs
and giants, especially longward of 8000Å
Ham = C. Hamilton, 1994 unpublished masters thesis
Her = Herbig, quoted in Walker, 1969ApJ...155..447W 1969ApJ...155..447W
HP = Herbig, private communication, 1996
HT = Herbig & Terndrup, 1986ApJ...307..609H 1986ApJ...307..609H or reference therein
J = Johnson, 1965ApJ...142..964J 1965ApJ...142..964J
LA = Levato & Abt, 1976PASP...88..712L 1976PASP...88..712L or
Abt & Levato, 1977PASP...89..797A 1977PASP...89..797A
LDW = Lallemand, Duchesne, & Walker, 1960PASP...72..268L 1960PASP...72..268L
M = McNamara, 1976AJ.....81..375M 1976AJ.....81..375M and 1976AJ.....81..845M 1976AJ.....81..845M
P = Prosser & Stauffer, unpublished
Par = Parenago, 1954, Cat. II/171
Petal = Penston, Hunter, & O'Neill, 1975MNRAS.171..219P 1975MNRAS.171..219P or
Penston, 1973ApJ...183..505P 1973ApJ...183..505P
S = Strand, 1958 reference (mostly to Sharpless)
Sam = A.E. Samuel, 1993 unpublished PhD thesis
SBB = Smith, Beckers, & Barden, 1983ApJ...271..237S 1983ApJ...271..237S
T = Trumpler, 1931PASP...43..255T 1931PASP...43..255T
vA = van Altena et al., 1988AJ.....95.1744
W = Walker, 1983ApJ...271..642W 1983ApJ...271..642W
WSH = Wolff, Strom, & Hillenbrand, 1998, in prep.
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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- 4 I4 --- ID Adopted identification number
5 A1 --- m_ID Multiplicity index on ID
7- 11 F5.2 mag AV ?=-9.99 Visual extinction (1)
13- 18 F6.3 [K] log(Teff) ?=-9.99 Effective temperature assigned from
spectral type
20- 24 F5.2 [solLum] log(L) ?=-9.99 Stellar luminosity (2)
26- 30 F5.2 solRad R ?=-9.99 Stellar radius calculated from
luminosity and effective temperature
32- 36 F5.2 solMass M ?=-9.99 Stellar mass (3)
38- 42 F5.2 [yr] log(age) ?=-9.99 Stellar age interpolated from D'Antona
& Mazitelli (1994ApJS...90..467D 1994ApJS...90..467D) isochrones
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Note (1): Visual extinction calculated from optical photometry
and spectral type; values of 0.00 indicate that the V-IC color
is too blue for the spectral type.
Note (2): Stellar luminosity calculated from application of a bolometric
correction to reddening-corrected photometry, assuming a distance of
470pc; see Table 1 for applicable cluster membership information.
luminosities are lower limits in cases where AV=0.0.
Note (3): Stellar mass interpolated from D'Antona & Mazitelli
(1994ApJS...90..467D 1994ApJS...90..467D) tracks for stars <3M☉, from Swenson
et al. (1994ApJ...425..286S 1994ApJ...425..286S) tracks for stars 3-5M☉, and from
the ZAMS mass-luminosity relationship for stars >5M☉.
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Acknowledgements: Lynne Hillenbrand
History:
* 04-Aug-1998: Original version
* 17-Mar-2006: Data corrected
(End) Patricia Bauer [CDS] 04-Aug-1998