J/A+A/627/A124 INT near-Earth asteroids spectroscopic survey (Popescu+, 2019)
Near-Earth asteroids spectroscopic survey at Isaac Newton Telescope.
Popescu M., Vaduvescu O., de Leon J., Gherase R.M., Licandro J., Boaca I.L.,
Sonka A.B., Ashley R.P., Mocnik T., Morate D., Predatu M., De Pra M.,
Farina C., Stoev H., Diaz Alfaro M., Ordonez-Etxeberria I.,
Lopez-Martinez F., Errmann R.
<Astron. Astrophys. 627, A124 (2019)>
=2019A&A...627A.124P 2019A&A...627A.124P (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Spectroscopy
Keywords: minor planets, asteroids: general - techniques: spectroscopic -
methods: observational
Abstract:
The population of near-Earth asteroids (NEAs) shows a large variety of
objects in terms of physical and dynamical properties. They are
subject to planetary encounters and to strong solar wind and radiation
effects. Their study is also motivated by practical reasons regarding
space exploration and long-term probability of impact with the Earth.
We aim to spectrally characterize a significant sample of NEAs with
sizes in the range of ∼0.25-5.5km (categorized as large), and
search for connections between their spectral types and the orbital
parameters.
Optical spectra of NEAs were obtained using the Isaac Newton Telescope
(INT) equipped with the IDS spectrograph. These observations are
analyzed using taxonomic classification and by comparison with
laboratory spectra of meteorites.
A total number of 76 NEAs were observed. We spectrally classified 44
of them as Q/S-complex, 16 as B/C-complex, eight as V-types, and
another eight belong to the remaining taxonomic classes. Our sample
contains 27 asteroids categorized as potentially hazardous and 31
possible targets for space missions including (459872) 2014 EK24,
(436724) 2011 UW158, and (67367) 2000 LY27. The spectral data
corresponding to (276049) 2002 CE26 and (385186) 1994 AW1 shows the
0.7um feature which indicates the presence of hydrated minerals on
their surface. We report that Q-types have the lowest perihelia (a
median value and absolute deviation of 0.797±0.244AU) and are
systematically larger than the S-type asteroids observed in our
sample. We explain these observational evidences by thermal fatigue
fragmentation as the main process for the rejuvenation of NEA
surfaces.
In general terms, the taxonomic distribution of our sample is similar
to the previous studies and matches the broad groups of the inner main
belt asteroids. Nevertheless, we found a wide diversity of spectra
compared to the standard taxonomic types.
Description:
The files contain optical spectra of near-Earth asteroids obtained
with Isaac Newton Telescope, Intermediate Dispersion Spectrograph
(IDS). The circumstances of the observations are shown in the log
file. The individual spectra of each asteroid are identified with the
prefix "spec", followed by the designation of the asteroid (number, if
available, otherwise the temporary designation). All spectra are
normalized to at 0.55 microns (i.e., the reflectance is 1 at 0.55
microns).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
log.dat 88 76 Observing information
spec/* . 76 Individual spectra
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Byte-by-byte Description of file: log.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Asteroid designation (Number or temp. desig.)
12- 15 F4.1 mag Vmag Apparent visual magnitude
17- 21 F5.1 deg Phi Phase angle
23- 29 F7.5 au r Heliocentric distance
31- 33 F3.1 arcsec Seeing Seeing
35- 50 A16 "datime" UT Mid time of observation YYYY-MM-DDThh:mm
52- 55 I4 s texp Total exposure time
57- 60 F4.2 --- AM Airmass
62- 70 A9 --- SA Solar Analogue used for obtaining the
reflectance
72- 88 A17 --- FileName Name of the spectrum file in subdirectory spec
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Byte-by-byte Description of file: spec/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 6 F6.4 um lambda Wavelength
8- 13 F6.4 --- refl Normalized reflectance
15- 20 F6.4 --- e_refl Reflectance error
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Acknowledgements:
Marcel Popescu, mpopescu(at)iac.es, popescu.marcel1983(at)gmail.com
(End) Marcel Popescu [IAC], Patricia Vannier [CDS] 02-Jul-2019