J/A+A/509/A94 Lightcurves of 14 NEAs (Kwiatkowski+, 2010)
Photometric survey of the very small near-Earth asteroids with the SALT
telescope.
I. Lightcurves and periods for 14 objects.
Kwiatkowski T., Buckley D.A.H., O'Donoghue D., Crause L., Crawford S.,
Hashimoto Y., Kniazev A., Loaring N., Romero Colmenero E., Sefako R.,
Still M., Vaisanen P.
<Astron. Astrophys. 509, A94 (2010)>
=2010A&A...509A..94K 2010A&A...509A..94K
ADC_Keywords: Solar system ; Minor planets ; Photometry, CCD ; Surveys
Keywords: techniques: photometric - minor planets, asteroids
Abstract:
We report first results from our extensive survey of the very small
(H>21.5mag) near-Earth asteroids. Our aim was to obtain photometric
lightcurves for these faint, fast moving objects and to measure their
rotation periods and amplitudes of light variations. These parameters
can be used to make statistical analysis of the still little known
population of the smallest asteroids, test present theories of the
YORP effect as well as to study their spin limits, which are connected
with their internal structure.
Due to the faintness of the targets and the expected short periods of
rotation, observations were performed with the large, 10-m SALT
telescope in SAAO (South Africa). For most asteroids, V filter images
with exposure times of 5-60 seconds were obtained with the
instrument's SALTICAM's CCD camera. Even though the non-sidereal
tracking was not available, the SALTICAM's relatively large
field-of-view of 8'x8' helped to perform the relative photometry of
the fast-moving targets.
The presented asteroids have synodic periods ranging from 77s to
44min, effective diameters from 21 to 94m, and significantly elongated
shapes.
Description:
Time-series relative photometry for 14 near-Earth asteroids is
presented as well as the aspect data, the observing log, and the
derived rotation parameters. For most asteroids several lightcurves
are reported, each of which was measured with a different comparison
star. For each asteroid a composite lightcurve is included, obtained
with the specified synodic rotation period. The period, together with
the shifts in magnitude of the individual data sets used in the
composite lightcurve, were obtained in a least-square fit of the
Fourier series of the specified order.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 24 Aspect data and observing log
table2.dat 43 17 Summary of the results
list.dat 65 44 List of all light curves
lc/* . 30 Individual light curves
clc/* . 14 Composite light curves
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See also:
J/A+A/465/331 : Asteroid brightness and geometry (Durech+, 2007)
J/A+A/498/313 : Photometry of 3 main belt asteroids (Marciniak+, 2009)
J/A+A/508/1503 : Photometry of 3 main belt asteroids (Marciniak+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Ast Designation of the asteroid
12- 21 A10 "YYYY/MM/DD" Obs1.date Observation date (beginning) (1)
23- 27 A5 "h:m" Obs1.time Observing time (beginning) (1)
29- 33 A5 "h:m" Obs2 Observing time (end) (1)
35- 40 F6.4 AU r Asteroid-Sun distance (2)
42- 47 F6.4 AU Delta Asteroid-Earth distance (2)
49- 52 F4.1 deg alpha Solar phase angle (2)
54- 58 F5.1 deg ELon Geocentric, ecliptic longitude (2)
60- 64 F5.1 deg ELat Geocentric, ecliptic latitude (2)
66- 69 F4.1 mag Vmag Apparent magnitude
71- 74 F4.1 arcsec/min pmov Asteroid movement on the sky
76- 77 I2 s texp Exposure time
79 A1 --- filt [VC] Kron-Cousins V or "clear" filter
81- 83 I3 --- N1 Number of exposures taken
85- 87 I3 --- N2 Number of exposures used
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Note (1): Observing runs which started on the next UTC night have hours
greater than 24h.
Note (2): Coordinates given for the middle of the observation
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Ast Asteroid designation
12- 20 F9.7 h Per Rotation period
22- 30 F9.7 h e_Per Period uncertainty (sigma)
32- 34 F3.1 mag Amp Peak-to-peak lightcurve amplitude
36- 38 F3.1 --- a/b Maximum elongation (1)
40- 44 F5.3 km Diam Effective diameter
46- 54 A9 --- File Corresponding figure and file,
in "clc" subdirectory
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Note (1): Actual a/b elongation is not greater than the given value
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Ast Asteroid name
12- 25 A14 --- FileName Name of the file containing the light curve
31- 65 A35 --- Title Title of the file
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Byte-by-byte Description of file: lc/*
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.7 d Date JD-2400000 (1)
15- 19 F5.3 mag mag Relative magnitude
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Note (1): not corrected for the light travel time
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Byte-by-byte Description of file: clc/*
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Bytes Format Units Label Explanations
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5- 13 F9.7 d Phase Rotation phase
15- 19 F5.3 mag mag Relative magnitude
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Acknowledgements:
Tomasz Kwiatkowski, tkastr(at)vesta.astro.amu.edu.pl
History:
* 28-Mar-2010: in table1 name "2007 YH14" was replaced by "2006 YH14"
(2007 YH14 can't be a near-Earth asteroid)
(End) T. Kwiatkowski [Poznan Obs., Poland], P. Vannier [CDS] 15-Feb-2010