J/MNRAS/434/806 Pre-main-sequence isochrones. II. SFR (Bell+, 2013)
Pre-main-sequence isochrones.
II. Revising star and planet formation time-scales.
Bell C.P.M., Naylor T., Mayne N.J., Jeffries R.D., Littlefair S.P.
<Mon. Not. R. Astron. Soc., 434, 806-831 (2013)>
=2013MNRAS.434..806B 2013MNRAS.434..806B
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ; Isochrones ;
Photometry
Keywords: techniques: photometric - stars: evolution - stars: formation -
stars: fundamental parameters -
Hertzsprung-Russell and colour-magnitude diagrams -
stars: pre-main-sequence
Abstract:
We have derived ages for 13 young (<30Myr) star-forming regions and
find that they are up to a factor of 2 older than the ages typically
adopted in the literature. This result has wide-ranging implications,
including that circumstellar discs survive longer (≃10-12Myr) and
that the average Class I lifetime is greater (≃1Myr) than currently
believed. For each star-forming region, we derived two ages from
colour-magnitude diagrams. First, we fitted models of the evolution
between the zero-age main sequence and terminal-age main sequence to
derive a homogeneous set of main-sequence ages, distances and
reddenings with statistically meaningful uncertainties. Our second age
for each star-forming region was derived by fitting pre-main-sequence
stars to new semi-empirical model isochrones. For the first time (for
a set of clusters younger than 50Myr), we find broad agreement between
these two ages, and since these are derived from two distinct mass
regimes that rely on different aspects of stellar physics, it gives us
confidence in the new age scale. This agreement is largely due to our
adoption of empirical colour-Teff relations and bolometric
corrections for pre-main-sequence stars cooler than 4000K.
The revised ages for the star-forming regions in our sample are:
∼2Myr for NGC 6611 (Eagle Nebula; M 16), IC 5146 (Cocoon Nebula),
NGC 6530 (Lagoon Nebula; M 8) and NGC 2244 (Rosette Nebula);
∼6Myr for σ Ori, Cep OB3b and IC 348;
∼10Myr for λ Ori (Collinder 69); ∼11Myr for NGC 2169;
∼12Myr for NGC 2362; ∼13Myr for NGC 7160;
∼14Myr for χPer (NGC 884); and ∼20Myr for NGC 1960 (M 36).
Description:
The observations presented were obtained using the 2.5m Isaac Newton
Telescope (INT) on La Palma at the same time as our Pleiades
observations described in Paper I (Bell et al., 2012MNRAS.424.3178B 2012MNRAS.424.3178B,
Cat. J/MNRAS/424/3178). We refer the reader to Paper I for details of
our observational techniques, photometric calibration and data
reduction.
24-Jan-2024:
This is an updated version of the catalogues correcting a bug whereby
some stars within about 3 arcseconds of each other were merged into a
single object in the final catalogue. Since the resulting object
always had the position of the brighter star, this resulted in a star
whose magnitude was too faint. The bug was fixed by using a smaller
radius search to define which stars in different observations were
likely to be the same star (1 arcsec vs 3 arcsec).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 66 19 The central coordinates for each field of view
and limiting magnitude in the INT-WFC
(UgriZ)WFC bandpasses (for a signal-to-noise
of 10) for our sample of SFRs
table2.dat 113 26 *Photometric catalogues presented in this study
refs.dat 111 39 References
table9.dat 282 68665 Cep OB3b Full catalogue
table10.dat 282 676 Cep OB3b Members catalogue
table11.dat 282 51922 χ Per Full catalogue
table12.dat 282 584 χ Per Members catalogue
table13.dat 282 20111 IC 348 Full catalogue
table14.dat 282 310 IC 348 Members catalogue
table15.dat 282 65761 IC 5146 Full catalogue
table16.dat 282 126 IC 5146 Members catalogue
table17.dat 282 103739 λ Ori Full catalogue
table18.dat 282 205 λ Ori Members catalogue
table19.dat 282 41236 NGC 1960 Full catalogue
table20.dat 282 54 NGC 1960 Members catalogue
table21.dat 282 33654 NGC 2169 Full catalogue
table22.dat 282 35 NGC 2169 Members catalogue
table23.dat 282 37323 NGC 2244 Full catalogue
table24.dat 282 522 NGC 2244 Members catalogue
table25.dat 282 53259 NGC 2362 Full catalogue
table26.dat 282 326 NGC 2362 Members catalogue
table27.dat 282 57492 NGC 6530 Full catalogue
table28.dat 282 663 NGC 6530 Members catalogue
table29.dat 282 51073 NGC 6611 Full catalogue
table30.dat 282 898 NGC 6611 Members catalogue
table31.dat 282 59798 NGC 7160 Full catalogue
table32.dat 282 90 NGC 7160 Members catalogue
table33.dat 282 90001 σ Ori Full catalogue
table34.dat 282 238 σ Ori Members catalogue
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Note on table2.dat: The members catalogues use the data where stars variable
from night to night have been replaced by the values from one night as
described in Paper I (Bell et al., 2012, Cat. J/MNRAS/424/3178).
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See also:
J/MNRAS/424/3178 : PMS isochrones. Pleiades benchmark (Bell+, 2012)
http://www.astro.ex.ac.uk/people/timn/Catalogues/ : The Cluster Collaboration
Home Page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SFR Cluster name
11- 12 A2 --- m_SFR Multiplicity index of central source
14- 15 I2 h RAh Right ascension (J2000.0)
17- 18 I2 min RAm Right ascension (J2000.0)
20- 23 F4.1 s RAs Right ascension (J2000.0)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 40 F4.1 mag Ulim ?=- Limiting magnitude in U WFC bandpass
42- 45 F4.1 mag glim Limiting magnitude in g WFC bandpass
47- 50 F4.1 mag rlim Limiting magnitude in r WFC bandpass
52- 55 F4.1 mag ilim Limiting magnitude in i WFC bandpass
57- 60 F4.1 mag Zlim Limiting magnitude in Z WFC bandpass
62- 63 I2 --- Fld1 [7/90] Minimal Field number in table 9-34
65- 66 I2 --- Fld2 [7/93] Maximal Field number in table 9-34
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- SFR Cluster name
12- 13 I2 --- Tab Table number
15- 16 I2 --- Fld1 [7/90] Minimal Field number in table 9-34
18- 19 I2 --- Fld2 [7/93] Maximal Field number in table 9-34
21- 34 A14 --- Desc Description
37-113 A77 --- Source Sources (1)
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Note (1): Sources used in the identification of pre-MS members in refs.dat file
(see also Appendix A).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 51 A28 --- Aut Author's name
53-111 A59 --- Com Comments
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Byte-by-byte Description of file (# headlines): table9.dat table??.dat
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Bytes Format Units Label Explanations
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3- 7 F5.2 --- Field [7.01/93.04] Field
11- 15 I5 --- ID [1/20799] Identification number
18- 19 I2 h RAh Right ascension (J2000.0)
21- 22 I2 min RAm Right ascension (J2000.0)
24- 29 F6.3 s RAs [0/60] Right ascension (J2000.0)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 42 F5.2 arcsec DEs [0/60] Declination (J2000)
46- 53 F8.3 pix Xpos X position
57- 64 F8.3 pix Ypos Y position
69- 75 F7.3 mag gmag WFC g magnitude
80- 86 F7.3 mag e_gmag [-99/99] rms uncertainty on gmag (2)
89- 90 A2 --- f_gmag Flag on gmag, OO=OK (1)
93- 99 F7.3 mag g-i WFC g-i colour index
104-110 F7.3 mag e_g-i [-99/127] rms uncertainty on g-i (2)
113-114 A2 --- f_g-i Flag on g-i, OO=OK (1)
117-123 F7.3 mag U-g WFC U-g colour index
129-134 F6.3 mag e_U-g [-99/99] rms uncertainty on U-g (2)
137-138 A2 --- f_U-g Flag on U-g, OO=OK (1)
140-147 F8.3 mag r-i WFC r-i colour index
152-158 F7.3 mag e_r-i [-99/127] rms uncertainty on r-i (2)
161-162 A2 --- f_r-i Flag on r-i, OO=OK (1)
165-171 F7.3 mag i-Z WFC i-Z colour index
177-182 F6.3 mag e_i-Z [-99/99] rms uncertainty on i-Z (2)
185-186 A2 --- f_i-Z Flag on i-Z, OO=OK (1)
189-195 F7.3 mag Umag WFC U magnitude
200-206 F7.3 mag e_Umag [-99/99] rms uncertainty on Umag (2)
209-210 A2 --- f_Umag Flag on Umag, OO=OK (1)
213-219 F7.3 mag rmag WFC r magnitude
224-230 F7.3 mag e_rmag [-99/99] rms uncertainty on rmag (2)
233-234 A2 --- f_rmag Flag on rmag, OO=OK (1)
237-243 F7.3 mag imag WFC i magnitude
248-254 F7.3 mag e_imag [-99/99] rms uncertainty on imag (2)
257-258 A2 --- f_imag Flag on imag, OO=OK (1)
261-267 F7.3 mag Zmag WFC Z magnitude
272-278 F7.3 mag e_Zmag [-99/99] rms uncertainty on Zmag (2)
281-282 A2 --- f_Zmag Flag on Zmag, OO=OK (1)
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Note (1): Quality flag (2 flags for a color index) as follows:
O = O.K. (clean detection)
A = Absent input data
B = Background fit failed [unused]
C = Large relative transparency correction (cloudy) [unused]
E = Too close to CCD edge
F = Flagged pixel
I = Ill-determined background [unused]
M = Negative (minus) counts
N = Non-stellar
P = Position fit failed [unused]
R = Uncalibrated region
S = Saturated
V = Variable
H = poor profile correction in the optimal photometry reduction
L = a star has been identified with counts above the pixel linearity
limit on the CCD during the pixel flagging procedure
W = photometry taken at a random position to test for the effects of
crowding in the field.
Note (2): the error is negative when there are negative counts (flag M).
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History:
24-Sep-2014: From electronic version of the journal
24-Jan-2024: tables updated
References:
Bell et al., Paper I 2012MNRAS.424.3178B 2012MNRAS.424.3178B, Cat. J/MNRAS/424/3178
(End) Patricia Vannier [CDS] 29-Jul-2014