J/A+A/687/A38 Asteroids spin orientation and phase function (Carry+, 2024)
Combined spin orientation and phase function of asteroids.
Carry B., Peloton J., Le Montagner R., Mahlke M., Berthier J.
<Astron. Astrophys. 687, A38 (2024)>
=2024A&A...687A..38C 2024A&A...687A..38C (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Photometry ; Optical ; Models
Keywords: methods: data analysis - techniques: photometric -
minor planets, asteroids: general
Abstract:
Large sky surveys provide numerous non-targeted observations of small
bodies of the Solar System. The upcoming Legacy Survey of Space and
Time (LSST) of the Vera C. Rubin observatory will be the largest
source of small body photometry in the next decade. With
non-coordinated epochs of observation, colors, and therefore taxonomy
and composition, can only be computed by comparing absolute magnitudes
obtained in each filter by solving the phase function (evolution of
brightness of the small body against the solar phase angle). Current
models in use in the community (HG, HG12*, HG1G2) however fail to
reproduce the long-term photometry of many targets due to the change
in aspect angle between apparitions. We aim at deriving a generic yet
simple phase function model accounting for the variable geometry of
the small bodies over multiple apparitions. As a spinoff of the HG1 G2
model, we propose the sHG1 G2 phase function model in which we
introduce a term describing the brightness changes due to spin
orientation and polar oblateness. We apply this new model to
13245908 observations of 122675 SSOs. These observations were
acquired in the g and r filters with the Zwicky Transient Facility
between 2019/11/01 and 2023/12/01. We retrieve them and implement the
new sHG1 G2 model in Fink, a broker of alerts designed for the LSST.
The sHG1 G2 model leads to smaller residuals than other phase function
models, providing a better description of the photometry of asteroids.
We determine the absolute magnitude H and phase function coefficients
(G1, G2) in each filter, the spin orientation (α0 , δ0),
and the polar-to-equatorial oblateness R for 95593 Solar System
Objects (SSOs), which constitutes about a tenfold increase in the
number of characterized objects compared to current census. The
application of the sHG1 G2 model on ZTF alert data using the FINK
broker shows that the model is appropriate to extract physical
properties of asteroids from multi-band and sparse photometry, such as
the forthcoming LSST survey.
Description:
We implemented the sHG1G2 model in FINK6, (Moeller et al.
2021MNRAS.501.3272M 2021MNRAS.501.3272M) a broker of alerts for the LSST (LSST
Collaboration 2009, arXiv e-prints [0912.0201] ). Today, before
the start of the LSST, FINK processes daily the public stream of
alerts from the Zwicky Transient Survey (ZTF; Masci et al.
2019PASP..131a8003M 2019PASP..131a8003M; Graham et al. 2019PASP..131g8001G 2019PASP..131g8001G; Bellm et al.
2019PASP..131a8002B 2019PASP..131a8002B; Patterson et al. 2019PASP..131a8001P 2019PASP..131a8001P).
We tested the new sHG1G2 model on observations in g and r, collected
over 3yr by the ZTF.
We used FINK to retrieve 19319067 observations of 565045 unique
SSOs in g and r between November 2019 and December 2023. We decided to
only retain objects with at least 50 observations across all filter
bands (122675 unique SSOs).
The resulting catalog is presented here.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 563 122675 FINK SSOFT (ZTF photometry, FINK broker)
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See also:
B/astorb : Orbits of Minor Planets (Bowell+, 2014-)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- SSOnumber ? Official IAU number (sso_number)
8- 24 A17 --- SSOname Official IAU designation (sso_name)
26- 28 I3 --- Nobs ? Total number of observations (n_obs)
30- 32 I3 --- Nobs-g ? Number of observations in g filter
(nobsg)
34- 36 I3 --- Nobs-r ? Number of observations in r filter
(nobsr)
38- 43 F6.2 --- Minphase ? Minimum phase angle of observations
(min_phase)
45- 50 F6.2 --- Minphase-g ? Minimum phase angle of observations
in g filter (minphaseg)
52- 57 F6.2 --- Minphase-r ? Minimum phase angle of observations
in r filter (minphaser)
59- 65 F7.2 --- Maxphase ? Maximum phase angle of observations
(max_phase)
67- 73 F7.2 --- Maxphase-g ? Maximum phase angle of observations
in g filter (maxphaseg)
75- 81 F7.2 --- Maxphase-r ? Maximum phase angle of observations
in r filter (maxphaser)
83- 88 F6.1 --- Ndays ? Number of days covered by
observations (n_days)
90- 95 F6.1 --- Ndays-g ? Number of days covered by
observations in g filter (ndaysg)
97-102 F6.1 --- Ndays-r ? Number of days covered by
observations in r filter (ndaysr)
104-109 F6.2 mag HG-H-g ? Absolute magnitude H in HG model
in g filter (HGHg)
111-116 F6.2 mag e_HG-H-g ? Uncertainty on the absolute
magnitude H in HG model
in g filter (HGdHg)
118-122 F5.2 --- HG-G-g ? Phase slope G in HG model in
g filter (HGGg)
124-129 F6.2 --- e_HG-G-g ? Uncertainty on phase slope G
in HG model in g filter (HGdGg)
131-136 F6.2 mag HG-H-r ? Absolute magnitude H in HG model
in r filter (HGHr)
138-142 F5.2 mag e_HG-H-r ? Uncertainty on the absolute
magnitude H in HG model
in r filter (HGdHr)
144-148 F5.2 --- HG-G-r ? Phase slope G in HG model in
r filter (HGGr)
150-155 F6.2 --- e_HG-G-r ? Uncertainty on phase slope G
in HG model in r filter (HGdGr)
157-161 F5.2 --- HG-rms ? RMS residuals of HG model (HG_rms)
163-167 F5.2 --- HG-rms-g ? RMS residuals of HG model
in g filter (HGrmsg)
169-173 F5.2 --- HG-rms-r ? RMS residuals of HG model
in r filter (HGrmsr)
175-182 F8.2 --- HG-chi2red ? Chi-square of HG model (HG_chi2red)
184-185 I2 --- HG-status Fit status of HG model (HG_status)
187 I1 --- HG-fit Quality code of the fit of HG model
(HG_fit)
189-194 F6.2 mag HG1G2-H-g ? Absolute magnitude H in HG1G2 model
in g filter (HG1G2Hg)
196-206 F11.2 mag e_HG1G2-H-g ? Uncertainty on the absolute
magnitude H in HG1G2 model
in g filter (HG1G2dHg)
208-212 F5.2 --- HG1G2-G1-g ? Phase slope G1 in HG1G2 model
in g filter (HG1G2G1g)
214-224 F11.2 --- e_HG1G2-G1-g ? Uncertainty on phase slope G1
in HG1G2 model in g filter
(HG1G2dG1g)
226-230 F5.2 --- HG1G2-G2-g ? Phase slope G2 in HG1G2 model
in g filter (HG1G2G2g)
232-242 F11.2 --- e_HG1G2-G2-g ? Uncertainty on phase slope G2
in HG1G2 model in g filter
(HG1G2dG2g)
244-249 F6.2 mag HG1G2-H-r ? Absolute magnitude H in HG1G2 model
in r filter (HG1G2Hr)
251-261 F11.2 mag e_HG1G2-H-r ? Uncertainty on the absolute
magnitude H in HG1G2 model
in g filter (HG1G2dHr)
263-267 F5.2 --- HG1G2-G1-r ? Phase slope G1 in HG1G2 model
in r filter (HG1G2G1r)
269-279 F11.2 --- e_HG1G2-G1-r ? Uncertainty on phase slope G1
in HG1G2 model in r filter
(HG1G2dG1r)
281-285 F5.2 --- HG1G2-G2-r ? Phase slope G2 in HG1G2 model
in r filter (HG1G2G2r)
287-296 F10.2 --- e_HG1G2-G2-r ? Uncertainty on phase slope G2
in HG1G2 model in r filter
(HG1G2dG2r)
298-302 F5.2 --- HG1G2-rms ? RMS residuals of HG1G2 model
(HG1G2_rms)
304-308 F5.2 --- HG1G2-rms-g ? RMS residuals of HG1G2 model
in g filter (HG1G2rmsg)
310-314 F5.2 --- HG1G2-rms-r ? RMS residuals of HG1G2 model
in r filter (HG1G2rmsr)
316-323 F8.2 --- HG1G2-chi2red ? Chi-square of HG1G2 model
(HG1G2_chi2red)
325-326 I2 --- HG1G2-status Fit status of HG1G2 model
(HG1G2_status)
328 I1 --- HG1G2-fit Quality code of the fit of HG1G2 model
(HG1G2_fit)
330-335 F6.2 mag SHG1G2-H-g ? Absolute magnitude H in sHG1G2 model
in g filter (SHG1G2Hg)
337-347 F11.2 mag e_SHG1G2-H-g ? Uncertainty on absolute magnitude H
in sHG1G2 model in g filter
(SHG1G2dHg)
349-353 F5.2 --- SHG1G2-G1-g ? Phase slope G1 in sHG1G2 model
in g filter (SHG1G2G1g)
355-365 F11.2 --- e_SHG1G2-G1-g ? Uncertainty on phase slope G1
in sHG1G2 model in g filter
(SHG1G2dG1g)
367-371 F5.2 --- SHG1G2-G2-g ? Phase slope G2 in sHG1G2 model
in g filter (SHG1G2G2g)
373-383 F11.2 --- e_SHG1G2-G2-g ? Uncertainty on phase slope G2
in sHG1G2 model in g filter
(SHG1G2dG2g)
385-390 F6.2 mag SHG1G2-H-r ? Absolute magnitude H in sHG1G2 model
in r filter (SHG1G2Hr)
392-402 F11.2 mag e_SHG1G2-H-r ? Uncertainty on absolute magnitude H
in sHG1G2 model in r filter
(SHG1G2dHr)
404-408 F5.2 --- SHG1G2-G1-r ? Phase slope G1 in sHG1G2 model
in r filter (SHG1G2G1r)
410-419 F10.2 --- e_SHG1G2-G1-r ? Uncertainty on phase slope G1
in sHG1G2 model in r filter
(SHG1G2dG1r)
421-425 F5.2 --- SHG1G2-G2-r ? Phase slope G2 in sHG1G2 model
in r filter (SHG1G2G2r)
427-436 F10.2 --- e_SHG1G2-G2-r ? Uncertainty on phase slope G2
in sHG1G2 model in r filter
(SHG1G2dG2r)
438-442 F5.2 --- SHG1G2-R ? Oblateness (SHG1G2_R)
444-450 F7.2 --- e_SHG1G2-R ? Uncertainty on oblateness
(SHG1G2_dR)
452-458 F7.2 deg SHG1G2-alpha0 ? Right Ascension of the spin vector
(SHG1G2_alpha0)
460-465 F6.2 deg SHG1G2-delta0 ? Declination of the spin vector
(SHG1G2_delta0)
467-473 F7.2 deg SHG1G2-alpha0-alt ? Right Ascension of the spin vector,
symmetric solution
(SHG1G2alpha0alt)
475-480 F6.2 deg SHG1G2-delta0-alt ? Declination of the spin vector,
symmetric solution
(SHG1G2delta0alt)
482-494 F13.2 deg e_SHG1G2-alpha0 ? Uncertainty on the Right Ascension
of the spin vector (SHG1G2_dalpha0)
496-506 F11.2 deg e_SHG1G2-delta0 ? Uncertainty on the Declination of
the spin vector (SHG1G2_ddelta0)
508-514 F7.2 deg SHG1G2-obliquity ? Obliquity of the target
(SHG1G2_obliquity)
516-520 F5.2 --- SHG1G2mincoslambda ? Minimum cosine of the aspect angle
Lambda (SHG1G2mincos_lambda)
522-526 F5.2 --- SHG1G2meancoslambda ? Mean cosine of the aspect angle
Lambda (SHG1G2meancos_lambda)
528-532 F5.2 --- SHG1G2maxcoslambda ? Maximum cosine of the aspect angle
Lambda (SHG1G2maxcos_lambda)
534-538 F5.2 --- SHG1G2-rms ? RMS residuals of sHG1G2 model
(SHG1G2_rms)
540-544 F5.2 --- SHG1G2-rms-g ? RMS residuals of sHG1G2 model
in g filter (SHG1G2rmsg)
546-550 F5.2 --- SHG1G2-rms-r ? RMS residuals of sHG1G2 model
in g filter (SHG1G2rmsr)
552-558 F7.2 --- sHG1G2-chi2red ? Chi-square of sHG1G2 model
(sHG1G2_chi2red)
560-561 I2 --- sHG1G2-status Fit status of sHG1G2 model
(sHG1G2_status)
563 I1 --- sHG1G2-fit Quality code of the fit of sHG1G2
model (sHG1G2_fit)
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Acknowledgements:
Benoit Carry, benoit.carry(at)oca.eu
(End) Patricia Vannier [CDS] 09-Apr-2024