J/A+A/345/521 BVRI photometry of NGC 2264 (Flaccomio+, 1999)
BVRI photometry of the star-forming region NGC 2264:
the initial mass function and star-forming rate
Flaccomio E., Micela G., Sciortino S., Favata F., Corbally C.,
Tomaney A.
<Astron. Astrophys. 345, 521 (1999)>
=1999A&A...345..521F 1999A&A...345..521F (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, UBVRI
Keywords: Galaxy: open clusters and associations: individual: NGC 2264 -
stars: pre-main sequence - stars: late-type - stars: formation
Abstract:
The pre-main-sequence (PMS) population in the mass range between
≃0.2 and ≃3M☉ in southern part of the star-forming region
NGC 2264 has been studied, determining both the Initial Mass Function
in the region as well as the star-formation rates for different mass
ranges. The sample is a composite one, derived through the union of
samples obtained through different techniques and each suffering from
different biases: previously known PMS stars in the region from the
literature, photometrically-selected T Tauri candidates (from our own
photometric data, discussed in detail in the present paper) and X-ray
selected PMS candidates (discussed in detail in a companion paper)
have been joined to form a sample which we show to be statistically
complete (i.e. free from the biases which affect each of the parent
samples) down to ≃0.6M☉ (while being incomplete at lower
masses). Individual masses and ages have been derived by placing the
individual stars on evolutionary tracks, allowing us to derive both
the IMF and the star formation rate. The Initial Mass Function thus
derived for NGC 2264 shows evidence for a bimodal distribution of
masses, with a break in the IMF at around 1M☉.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 55 520 Catalog of CCD photometry
table5.dat 106 141 Catalog of observed NGC 2264 members
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number
4 A1 --- n_Seq [+] + when present in table5.dat file
5 I1 --- uPhot [0/1] 1: Uncertain photometry
7- 8 I2 h RAh Right ascension (J2000)
10- 11 I2 min RAm Right ascension (J2000)
13- 16 F4.1 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 28 F4.1 arcsec DEs Declination (J2000)
30- 34 F5.2 mag Vmag Visual magnitude
36- 40 F5.2 mag B-V B-V colour index
42- 46 F5.2 mag V-R ? V-R colour index
48- 52 F5.2 mag R-I ? R-I colour index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Identification number
5 I1 --- uPhot [0/1] 1: uncertain photometry
7- 8 I2 h RAh Right ascension (J2000)
10- 11 I2 min RAm Right ascension (J2000)
13- 16 F4.1 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 28 F4.1 arcsec DEs Declination (J2000)
30- 34 F5.2 mag Vmag Visual Magnitude
36- 40 F5.2 mag B-V B-V colour Index
42- 46 F5.2 mag V-R ? V-R colour Index
48- 52 F5.2 mag R-I ? R-I colour Index
54- 58 F5.2 [solLum] Log(Lbol) ? Bolometric Luminosity
60- 63 F4.2 [K] Log(Teff) ? Effective Temperature
65- 68 F4.2 solMass Mass ? Mass
70- 73 F4.2 [yr] Log(Age) ? Logarithm of Age
75- 77 A3 --- Memb Membership criteria (1)
79-106 A28 --- Ident Cross identifications (2)
--------------------------------------------------------------------------------
Note (1): Membership criteria:
c: this paper (see text);
x: Flaccomio et al. (in prep.);
h: Herbig (1954ApJ...119..483H 1954ApJ...119..483H), Marcy (1980AJ.....85..230M 1980AJ.....85..230M),
Ogura (1984PASJ...36..139O 1984PASJ...36..139O) or Sung et al. (1997AJ....114.2644S 1997AJ....114.2644S)
p: Vasilevskis et al. (1965AJ.....70..797V 1965AJ.....70..797V) with membership
probabilities >50%.
Note (2): A prefix, indicating the original catalog, is followed by the
reference number used by the authors of the catalog.
The prefixes stand for:
W: Walker (1956ApJS....2..365W 1956ApJS....2..365W)
V: Vasilevskis et al. (1965AJ.....70..797V 1965AJ.....70..797V)
S: Sung et al. (1997AJ....114.2644S 1997AJ....114.2644S)
O: Ogura (1984PASJ...36..139O 1984PASJ...36..139O)
M: Marcy (1980AJ.....85..230M 1980AJ.....85..230M)
H: Herbig (1954ApJ...119..483H 1954ApJ...119..483H)
FX: Flaccomio et al. (in prep.)
--------------------------------------------------------------------------------
Acknowledgements: Ettore Flaccomio
(End) Patricia Bauer [CDS] 27-Apr-1999