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J/A+A/522/A93    Short-term variability of 29 minor planets    (Thirouin+, 2010)

Short-term variability of a sample of 29 trans-Neptunian objects and Centaurs. Thirouin A., Ortiz J.L., Duffard R., Santos-Sanz P., Aceituno F.J., Morales N. <Astron. Astrophys. 522, A93 (2010)> =2010A&A...522A..93T
ADC_Keywords: Minor planets ; Photometry Keywords: Kuiper Belt: general - techniques: photometric Abstract: We present results of 6 years of observations, reduced and analyzed with the same tools in a systematic way. We present completely new data on 15 objects (1998SG35, 2002GB10, 2003EL61, 2003FY128, 2003MW12, 2003OP32, 2003WL7, 2004SB60, 2004UX10, 2005CB79, 2005RM43, 2005RN43, 2005RR43, 2005UJ438, 2007UL126 (or 2002KY14)), for 5 objects we present a new analysis of previously published results plus additional data (2000WR106, 2002CR46, 2002TX300, 2002VE95, 2005FY9) and for 9 objects we present a new analysis of data already published (1996TL66, 1999TZ1, 2001YH140, 2002AW197, 2002LM60, 2003AZ84, 2003CO1, 2003VS2, 2004DW). Lightcurves, possible rotation periods and photometric amplitudes are reported for all of them. The photometric variability is smaller than previously thought: the mean amplitude of our sample is 0.1mag and only around 15% of our sample has a larger variability than 0.15mag. The smaller variability than previously thought seems to be a bias of previous observations. We find a very weak trend of faster spinning objects towards smaller sizes, which appears to be consistent with the fact that the smaller objects are more collisionally evolved, but could also be a specific feature of the Centaurs, the smallest objects in our sample.We also find that the smaller the objects, the larger their amplitude, which is also consistent with the idea that small objects are more collisionally evolved and thus more deformed. Average rotation rates from our work are 7.5h for the whole sample, 7.6h for the TNOs alone and 7.3h for the Centaurs. All of them appear to be somewhat faster than what one can derive from a compilation of the scientific literature and our own results. Maxwellian fits to the rotation rate distribution give mean values of 7.5h (for the whole sample) and 7.3h (for the TNOs only). Assuming hydrostatic equilibrium we can determine densities from our sample under the additional assumption that the lightcurves are dominated by shape effects, which is likely no realistic. The resulting average density is 0.92g/cm3 which is not far from the density constraint that one can derive from the apparent spin barrier that we observe. Description: The time series photometry of all the objects is provided as Table 3. We highlighted in bold face the times corresponding to the images that we used to obtain an R magnitude calibration. The rest of the R magnitudes in the table was obtained by using the relative magnitude information. Also, in table 1 are geometric data such as geocentric and heliocentric distances. The R magnitudes that the TNOs would have if they were at 1AU from the Earth and the Sun (mR(1,1)) are also shown. No phase corrections were applied. In table 3, we present our photometric results: the name of the object and for each image we specify the Julian date (not corrected for travel time), the Relative magnitude [mag] and the 1-sigma error associated [mag], the R magnitude [mag], the filter used during observational runs, the phase angle (phi) [deg], topocentric (rh) and heliocentric (Delta) distances [AU] and the magnitude [mag] at 1AU from the Earth and at 1AU from the Sun. We highlight in bold face the date of the image in which we performed a crude absolute calibration. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 63 29 List of studied objects table1.dat 69 239 Dates, geometric and photometric data of the observations table3.dat 87 5377 Photometric results table3.tex 572 5386 Latex version of the table
See also: B/astorb : Orbits of Minor Planets (Bowell+ 2010) J/A+A/468/L13 : Photometry of the trans-Neptunian object 2005FY9 (Ortiz+, 2007) J/AJ/133/26 : Solar phase curves of distant icy bodies (Rabinowitz+, 2007) J/A+A/508/451 : Light curves of 5 Trans-Neptunian Objects (Perna+, 2009) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
2- 7 I6 --- Planet ? Planet number, if assigned (G1) 10- 19 A10 --- Name Planet name (G1) 25- 29 F5.2 mag H ? Absolute magnitude H parameter 32- 40 F9.6 deg i ? Orbit inclination 42- 51 F10.8 --- e ? Orbit eccentricity 53- 63 F11.8 AU a ? Orbit semimajor axis
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
2- 7 I6 --- Planet ? Planet number, if assigned (G1) 10- 19 A10 --- Name Planet name (G1) 24- 33 A10 "DD/MM/YYYY" Date Observation date 35- 37 I3 --- Nimg Number of images 39- 44 F6.3 AU rh Topocentric distance 46- 51 F6.3 AU delta Heliocentric distance 53- 56 F4.2 deg phi Phase angle 58 A1 --- Filt [R] Filter used 60- 69 A10 --- Tel Telescope: Calar Alto, INT or OSN (1)
Note (1): Telescopes are: Calar Alto = 2.2m at Calar Alto Obs. (Almeria, Spain) INT = 2.5m Isaac Newton Telescope at El Roque de Los Muchachos (Spain) OSN = 1.5m telescope at Sierra Nevada Obs. (Granada, Spain)
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
2- 7 I6 --- Planet ? Planet number, if assigned (G1) 10- 19 A10 --- Name Planet name (G1) 23 A1 --- n_JD [*] * for the date of the image in which we performed a crude absolute calibration 25- 37 F13.5 d JD Julian date, not corrected for travel time 39- 44 F6.3 mag relmag Relative magnitude 46- 50 F5.3 mag e_relmag 1-σ error associated to relmag 52- 56 F5.2 mag Rmag R magnitude 58- 62 A5 --- Filter Filter used during observational runs (Clear or R) 64- 67 F4.2 deg phi Phase angle 69- 74 F6.3 AU rh Topocentric distance 76- 81 F6.3 AU delta Heliocentric distance 83- 87 F5.2 mag mR(1,1) Magnitude at 1AU from the Earth and at 1AU from the Sun
Global notes: Note (G1): Planet names and numbers as in the "Astorb" data-base (Cat. B/astorb)
Acknowledgements: Audrey Thirouin, thirouin(at)
(End) Patricia Vannier [CDS] 27-Aug-2010
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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