J/MNRAS/504/3730 Synthetic RGB photometry of bright stars (Cardiel+, 2021)
Synthetic RGB photometry of bright stars: definition of the standard photometric
system and UCM library of spectrophotometric spectra.
Cardiel N., Zamorano J., Bara S., Sanchez de Miguel A., Cabello C.,
Gallego J., Garcia L., Gonzalez R., Izquierdo J., Pascual S., Robles J.,
Sanchez A., Tapia C.
<Mon. Not. R. Astron. Soc. 504, 3730 (2021)>
=2021MNRAS.504.3730C 2021MNRAS.504.3730C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Photometry, CCD
Keywords: techniques: photometric - catalogues - stars: general
Abstract:
Although the use of RGB photometry has exploded in the last decades
due to the advent of high-quality and inexpensive digital cameras
equipped with Bayer-like colour filter systems, there is surprisingly
no catalogue of bright stars that can be used for calibration
purposes. Since due to their excessive brightness, accurate enough
spectrophotometric measurements of bright stars typically cannot be
performed with modern large telescopes, we have employed historical
13-colour medium-narrow-band photometric data, gathered with quite
reliable photomultipliers, to fit the spectrum of 1346 bright stars
using stellar atmosphere models. This not only constitutes a useful
compilation of bright spectrophotometric standards well spread in the
celestial sphere, the UCM library of spectrophotometric spectra, but
allows the generation of a catalogue of reference RGB magnitudes, with
typical random uncertainties ∼0.01 mag. For that purpose, we have
defined a new set of spectral sensitivity curves, computed as the
median of 28 sets of empirical sensitivity curves from the literature,
that can be used to establish a standard RGB photometric system.
Conversions between RGB magnitudes computed with any of these sets of
empirical RGB curves and those determined with the new standard
photometric system are provided. Even though particular RGB
measurements from single cameras are not expected to provide extremely
accurate photometric data, the repeatability and multiplicity of
observations will allow access to a large amount of exploitable data
in many astronomical fields, such as the detailed monitoring of light
pollution and its impact on the night sky brightness, or the study of
meteors, Solar system bodies, variable stars, and transient objects.
In addition, the RGB magnitudes presented here make the sky an
accessible and free laboratory for the calibration of the cameras
themselves.
Description:
Full Table 2 from the paper, providing RGB magnitude estimates for the
1346 bright star sample comprising the UCM library of
spectrophotometric standards. The synthetic photometry has been
computed using the spectral energy distributions obtained through the
fit of stellar atmosphere models to historical, but quite reliable,
13-colour photometric data from the literature.
Full Table 5 from the paper, with the median spectral sensitivity
curves computed from the database of 28 cameras measured by Jiang et
al. (2013).
Additional data (FITS/ASCII spectra for the 1346 stars) are available
at https://guaix.ucm.es/rgbphot
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 307 1346 Catalogue with RGB magnitudes for 1346 stars
table3.dat 77 34 Double stars from the JM75 (Johnson & Mitchell,
1975RMxAA...1..299J 1975RMxAA...1..299J, Cat. II/84) sample for
which the individual fluxes of the two stars
have been coadded to derive the resulting
integrated B and V magnitudes.
table5.dat 34 35 RGB spectral sensitivity curves
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See also:
V/50 : Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2017)
https://guaix.ucm.es/rgbphot : RGB photometry Home Page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- HR Harvard Revised Number = Bright Star Number
6- 16 F11.7 deg RAdeg Right ascension (J2000)
18- 28 F11.7 deg DEdeg Declination (J2000)
30- 40 A11 --- DbleName Identification of double star companion (1)
42- 50 A9 --- VarName Identification if star is a known
variable (2)
52- 61 A10 --- VarType Variability type (3)
63- 71 F9.6 10-11W/m2 f33 Flux density in the 33 (0.33um) filter
in 10-9erg/s/cm-2/Å unit
73- 81 F9.6 10-11W/m2 f35 Flux density in the 35 (0.35um) filter
in 10-9erg/s/cm-2/Å unit
83- 91 F9.6 10-11W/m2 f37 Flux density in the 37 (0.37um) filter
in 10-9erg/s/cm-2/Å unit
93-101 F9.6 10-11W/m2 f40 Flux density in the 40 (0.40um) filter
in 10-9erg/s/cm-2/Å unit
103-111 F9.6 10-11W/m2 f45 Flux density in the 45 (0.45um) filter
in 10-9erg/s/cm-2/Å unit
113-121 F9.6 10-11W/m2 f52 Flux density in the 52 (0.52um) filter
in 10-9erg/s/cm-2/Å unit
123-131 F9.6 10-11W/m2 f58 Flux density in the 58 (0.58um) filter
in 10-9erg/s/cm-2/Å unit
133-140 F8.6 10-11W/m2 f63 Flux density in the 63 (0.63um) filter
in 10-9erg/s/cm-2/Å unit
142-149 F8.6 10-11W/m2 f72 ?=- Flux density in the 72 (0.72um) filter
in 10-9erg/s/cm-2/Å unit
151-158 F8.6 10-11W/m2 f80 ?=- Flux density in the 80 (0.80um) filter
in 10-9erg/s/cm-2/Å unit
160-167 F8.6 10-11W/m2 f86 ?=- Flux density in the 86 (0.68um) filter
in 10-9erg/s/cm-2/Å unit
169-176 F8.6 10-11W/m2 f99 ?=- Flux density in the 99 (0.99um) filter
in 10-9erg/s/cm-2/Å unit
178-185 F8.6 10-11W/m2 f110 ?=- Flux density in the 110 (1.10um) filter
in 10-9erg/s/cm-2/Å unit
187-191 I5 K Teff Effective temperature from fit to
CK04 model (4)
193-196 I4 K e_Teff Uncertainty in Teff
198-202 F5.3 [cm/s2] logg Logarithm of the surface gravity
204-208 F5.3 [cm/s2] e_logg Uncertainty in logg
210-215 F6.3 --- Metal Metallicity
217-221 F5.3 --- e_Metal Uncertainity in Metal
223-230 F8.4 --- csc Scaling factor: fluxes -> flux densities
232-236 F5.2 mag Bsimbad ?=- Johnson B mag (from Simbad, '---' if NA)
238-242 F5.2 mag Vsimbad ?=- Johnson V mag (from Simbad, '---' if NA)
244-249 F6.3 mag Bck04 Johnson B mag measured in fitted
CK04 model (4)
251-255 F5.3 mag e_Bck04 Uncertainty in Bck04
257-262 F6.3 mag Vck04 Johnson V mag measured in fitted
CK04 model (4)
264-268 F5.3 mag e_Vck04 Uncertainty in Vck04
270-275 F6.3 mag Brgb Standard blue RGB estimate
277-281 F5.3 mag e_Brgb Uncertainty in Brgb
283-288 F6.3 mag Grgb Standard green RGB estimate
290-294 F5.3 mag e_Grgb Uncertainty in Grgb
296-301 F6.3 mag Rrgb Standard red RGB magnitude
303-307 F5.3 mag e_Rrgb Uncertainty in Rrgb
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Note (1): See Table 3 from the paper. Stars marked with an asterisk in that
table were removed from the final sample due to large discrepancies between
the Simbad data and the predicted B and V magnitudes.
Empty fields are filled with a '---' string.
Note (2): Additional name when de star is a known variable according to Simbad.
Empty fields are filled with a '---' string.
Note (3): See https://cdsarc.unistra.fr/ftp/B/gcvs/vartype.txt
in General Catalogue of Variable Stars: B/gcvs
Empty fields are filled with a '---' string.
Note (4): CK04: Castelli & Kurucz, 2003 Proc. IAU Symp. 210, A20.
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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 A1 --- Flag [*] Note (1)
2- 7 A6 --- Star1 Initial star identification provided in JM75,
HRNNNN
9- 13 F5.3 mag B1mag ?=- B magnitude of Star 1 (from Simbad)
15- 19 F5.3 mag V1mag ?=- V magnitude of Star 1 (from Simbad)
21- 27 A7 --- SpType1 Spectral type of Star 1 (from Simbad)
29- 40 A12 --- Star2 Companion star (in some cases the companion
star is brighter than Star1) (2)
42- 47 F6.3 mag B2mag ?=- B magnitude of Star 2 (from Simbad)
49- 53 F5.3 mag V2mag ?=- V magnitude of Star 2 (from Simbad)
55- 64 A10 --- SpType2 Spectral type of Star 2 (from Simbad)
66- 70 F5.3 mag Vmag ?=- V magnitude for Star1+Star2
72- 77 F6.3 mag Bmag ?=- V magnitude for Star1+Star2
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Note (1): Stars marked with an asterisk in the first column were finally
removed from the final sample due to large discrepancies between the Simbad
data and the predicted B and V magnitudes, as explained in Section 4.3
Note (2): The fourth column in Table 2 provides the name of the companion star
for the double star systems incorporated in the final stellar sample.
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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- 4 I4 0.1nm lambda Wavelength
6- 14 F9.7 --- stdB Spectral sensitivity of standard B band
16- 24 F9.7 --- stdG Spectral sensitivity of standard G band
26- 34 F9.7 --- stdR Spectral sensitivity of standard R band
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Acknowledgements:
Nicolas Cardiel, cardiel(at)ucm.es
(End) Patricia Vannier [CDS] 28-May-2021