J/A+A/676/A126 NEA 2023 DZ2 spectro-photometry (Popescu+, 2023)
Discovery and physical characterization as the first response to a potential
asteroid collision: The case of 2023 DZ2.
Popescu M.M., Vaduvescu O., de Leon J., de la Fuente Marcos C.,
de la Fuente Marcos R., Stanescu M.O., Alarcon M.R., Serra Ricart M.,
Licandro J., Bertesteanu D., Predatu M., Curelaru L., Barwell F., Jhass K.,
Boldea C., Aznar Macias A., Hudin L., Dumitru B.A.,
<Astron. Astrophys. 676, A126 (2023)>
=2023A&A...676A.126P 2023A&A...676A.126P (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets ; Photometry ; Spectroscopy
Keywords: minor planets, asteroids: individual: 2023 DZ2 -
techniques: spectroscopic - techniques: photometric -
methods: observational - methods: numerical - celestial mechanics
Abstract:
Near-Earth asteroids (NEAs) that may evolve into impactors deserve
detailed threat assessment studies. Early physical characterization of
a would-be impactor may help in optimizing impact mitigation plans. We
first detected NEA 2023 DZ2 on 27 February 2023. After that, it was
found to have a minimum orbit intersection distance (MOID) with Earth
of 0.00005au as well as an unusually high initial probability of
becoming a near-term (in 2026) impactor. We perform a rapid but
consistent dynamical and physical characterization of 2023 DZ2 as an
example of a key response to mitigating the consequences of a
potential impact. We used a multi-pronged approach, drawing from
various methods (observational-computational) and techniques
(spectroscopy-photometry from multiple instruments), and bringing
the data together to perform a rapid and robust threat assessment. The
visible reflectance spectrum of 2023 DZ2 is consistent with that of an
X-type asteroid. Light curves of this object obtained on two different
nights give a rotation period P=6.2743±0.0005 min with an
amplitude A=0.57±0.14mag. We confirm that although its MOID is
among the smallest known, 2023 DZ2 will not impact Earth in the
foreseeable future as a result of secular near-resonant behaviour. Our
investigation shows that coordinated observation and interpretation of
disparate data provides a robust approach from discovery to threat
assessment when a virtual impactor is identified.
Description:
Based on observations made with the Gran Telescopio Canarias (GTC)
telescope and the Isaac Newton Telescope (INT), in the Spanish
Observatorio del Roque de los Muchachos of the Instituto de
Astrofisica de Canarias (programme IDs GTC31-23A and
INT99-MULTIPLE-2/23A), and the Two-Meter Twin Telescope (TTT) and the
Telescopio Carlos Sanchez (TCS), in the Spanish Observatorio del Teide
of the Instituto de Astrofisica de Canarias.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
specphot.dat 254 1 TCS Spectro-photometric data
spectrum.dat 19 441 GTC visible spectroscopy (2023/03/20)
phot-073.dat 28 2771 Lightcurve obtained by 073 Observatory
phot-l04.dat 28 242 Lightcurve obtained by L04 Observatory
phot-295.dat 28 274 Lightcurve obtained by 073 Observatory
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Byte-by-byte Description of file: specphot.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- PDesign Asteroid designation in the
Minor Planet Center packed format
9- 16 A8 --- MDesign Asteroid temporary designation
18- 36 A19 "datime" UTstart Start of TCS observations, UT time,
in the format YYYY-MM-DDTHH:MM:SS
38- 42 F5.2 mag Vmag Apparent V magnitude of the asteroid at
the start of observations,
provided by JPL Horizons
44- 47 F4.2 arcsec/min mu Differential rate of the asteroid at the
start of observations
49- 58 F10.8 au rhelioc Heliocentric distance at the start of
observations, provided by JPL Horizons
60- 69 F10.8 au rgeo Geocentric distance at the start of
observations, provided by JPL Horizons
71- 78 F8.4 deg RAdeg Right ascension at the start of
observations (UTstart),
provided by JPL Horizons
80- 87 F8.5 deg DEdeg Declination at the start of observations,
(UTstart) provided by JPL Horizons
89- 92 F4.1 deg Phi Phase Angle at the start of observations,
provided by JPL Horizons
94- 99 F6.4 h gTTObsh Total time of observation in g filter
101-103 I3 --- gNImags Number of exposure obtained with g filter
105-111 F7.4 mag gMeanVal Average magnitude in g filter
113-118 F6.4 mag gErrPerObs Photometric error per exposure in g filter
120-125 F6.4 h rTTObsh Total time of observation in r filter
127-129 I3 --- rNImags Number of exposure obtained with g filter
131-137 F7.4 mag rMeanVal Average magnitude in r filter
139-144 F6.4 mag rErrPerObs Photometric error per exposure in r filter
146-151 F6.4 h iTTObsh Total time of observation in i filter
153-155 I3 --- iNImags Number of exposure obtained with i filter
157-163 F7.4 mag iMeanVal Average magnitude in i filter
165-170 F6.4 mag iErrPerObs Photometric error per exposure in i filter
172-177 F6.4 h zTTObsh Total time of observation in zs filter
179-181 I3 --- zNImags Number of exposure obtained with
zs filter
183-189 F7.4 mag zMeanVal Average magnitude in zs filter
191-196 F6.4 mag zErrPerObs Photometric error per exposure in
zs filter
198-203 F6.4 mag g-r (g-r) median color index
205-211 F7.5 mag e_g-r (g-r) median color error
213-218 F6.4 mag r-i (r-i) median color index
220-225 F6.4 mag e_r-i (r-i) median color error
227-232 F6.4 mag i-z (i-z_s) median color index
234-240 F7.5 mag e_i-z (i-z_s) median color error
242 A1 --- KNN-tax [X] Taxonomic classification using
KNN algorithm
244 I1 --- KNN-prob [1] Probability for the taxonomic class
assigned using KNN
246 A1 --- RF-tax [X] Taxonomic classification using
RF algorithm
248-252 F5.3 --- RF-prob [0.999] Probability for the taxonomic
class assigned using RF
254 A1 --- Final-tax [X] Assigned taxonomic classification
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Byte-by-byte Description of file: spectrum.dat
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Bytes Format Units Label Explanations
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1- 5 F5.3 um lambda Wavelength in microns
7- 12 F6.4 --- Reflect Reflectance, normalized at 0.55 microns
14- 19 F6.4 --- e_Reflect Reflectance error
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Byte-by-byte Description of file: phot-073.dat phot-295.dat phot-l04.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d JD Julian Day
16- 22 F7.3 mag mag Apparent magnitude
24- 28 F5.3 mag e_mag Apparent magnitude error
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History:
From Marcel Popescu, popescu.marcel1983(at)gmail.com
Acknowledgements:
The work of M.P., O.V., M.S., D.B., L.C. and M.P., was supported by a
grant of the Romanian National Authority for Scientific Research
UEFISCDI, project number PN-III-P2-2.1-PED-2021-3625. RdlFM and CdlFM
thank S.J. Aarseth for providing one of the codes used in this
research and A.I. Gomez de Castro for providing access to computing
facilities. This work was partially supported by the Spanish "Agencia
Estatal de Investigacion (Ministerio de Ciencia e Innovacion)" under
grant PID2020-116726RB-I00/AEI/10.13039/501100011033. Based on
observations made with the Isaac New- ton Telescope (INT), in the
Spanish Observatorio del Roque de los Muchachos of the Instituto de
Astrofisica de Canarias (program ID INT99-MULTIPLE- 2/23A). Based on
observations made with the Gran Telescopio Canarias (GTC), installed
at the Spanish Observatorio del Roque de los Muchachos of the
Instituto de Astrofisica de Canarias, on the island of La Palma. This
work is partly based on data obtained with the instrument OSIRIS,
built by a Consortium led by the Instituto de Astrofisica de Canarias
in collaboration with the Instituto de Astronomia of the Universidad
Nacional Autonoma de Mexico. OSIRIS was funded by GRANTECAN and the
National Plan of Astronomy and Astro- physics of the Spanish
Government.This paper includes observations made with the Two meter
Twin Telescope (TTT) at the IAC's Teide Observatory that Light
Bridges, SL, operates on the Island of Tenerife, Canary Islands
(Spain). The Observing Time Rights (DTO) used for this research at the
TTT have been provided by the Instituto de Astrofisica de Canarias.
The spectral and the spectro-photometric data were obtained in the
framework of the European Union's Horizon 2020 research and
innovation program under grant agreement No 870403 (NEOROCKS). JL,
JdeL, M.R-A and MP acknowledge support from the ACIISI, Consejeria de
Economia, Conocimiento y Empleo del Gobierno de Canarias and the
European Regional Development Fund (ERDF) under grant with reference
ProID2021010134. In preparation of this paper, we made use of the NASA
Astrophysics Data System, the ASTRO-PH e-print server, and the MPC
data server. We thank the reviewers for their comments which helped us
to improve the paper. We also thank to Dr. Hissa Medeiros for the
discussions on this topic and for the suggested references, to Gabriel
Nicolae Simon for providing the python functions used for the
spectro-photometric classification.
(End) Marcel M. Popescu [AIRA, Romania], Patricia Vannier [CDS] 01-Aug-2023