arXiv subjects

Javier Licandro

Publications and source records attributed to Javier Licandro.

At least 19 recordsLinked to original sources

arXiv2026

Long-baseline ATLAS photometry of the seven main-belt asteroid targets of the Emirates Mission to the Asteroid Belt

The Emirates Mission to the Asteroid Belt (EMA) will use the MBR Explorer spacecraft to fly past six main-belt asteroids -- (10253) Westerwald, (623) Chimaera, (13294) Rockox, (88055) Ghaf, (23871) Ousha and (59980) Moza -- before rendezvousing with, and deploying a lander onto, the extremely red (269) Justitia. We present a homogeneous analysis of a decade of sparse photometry of all seven targets from the Asteroid Terrestrial-impact Last Alert System (ATLAS). For each object we derive absolute magnitudes and phase slopes in the ATLAS c and o bands, the c-o colour on a common phase slope, a rotation period from a Lomb-Scargle periodogram of the phase-corrected light curve, and a light-curve amplitude setting a lower limit on elongation. Five periods are secure -- 3.243 h for Rockox, 33.1 h for Justitia, 3.64 h for Westerwald, 14.6 h for Chimaera and 4.36 h for Moza -- and agree with independent work; for Ousha aliasing leads us to adopt the published 8.35 h, while Ghaf remains unresolved. Lightcurve inversion gives a unique convex shape and spin state for Rockox and two pole solutions for Chimaera, Moza and Justitia; no model was obtained for Ghaf, Ousha or Westerwald, though Westerwald's spin axis must be retrograde. Combining the c-o colour with an albedo class from the phase slope, we classify the sample as one dark C-type (Chimaera), three probable S-types (Westerwald, Ghaf, Moza), two X-complex objects (Rockox, plausibly M-type, and Ousha, possibly E-type), and the exceptionally red L/D-type Justitia, whose (c-o) = 0.48 is redder than typical Jupiter Trojans. This only partly matches the mission's family-based expectation of a predominantly primitive target set, so we present these as testable predictions. Those of Ghaf and Ousha are least secure -- both disagree with published work and have unresolved or aliased periods -- and warrant follow-up.

astro-ph.EP↗

arXiv2026

The Polana-Eulalia Complex with JWST NIRSpec: Connections to Bennu, Ryugu, and Outer Solar System Bodies

Carbon rich [C complex] asteroids provide insight into the early Solar System, and families of C complex asteroids serve as robust samples for learning about the internal structure of planetesimals and the materials of the protoplanetary disk. This work investigates the compositions of asteroids within the Polana Eulalia Complex [PEC] through analyses of JWST NIRSpec. Obtained as part of the Spectral Analysis of Main Belt Asteroids in the 3 um Region [SAMBA3] project. NIRSpec observations were conducted for the namesake asteroid of the Eulalia family, [495] Eulalia, as well as three members from the Polana family: [2441] Hibbs, [6712] Hornstein, and [6769] Brokoff. Analyses of the 2.7 um region demonstrate that PEC asteroids exhibit absorptions associated with Mg rich phyllosilicates, in turn underscoring high, though incomplete, degrees of aqueous alteration in the past for both PEC families. Although consistent in regard to composition, [142] Polana and [495] Eulalia show deeper 2.7 um bands than the Polana family asteroids, suggesting slight differences in the degrees of aqueous alteration between large and small PEC asteroids. Minor absorptions from 3.0 to 4.0 um indicate that [495] Eulalia's surface may contain more carbonates than [142] Polana, which potentially highlights slight differences between each family's formation and evolution. Additionally, PEC asteroids also show spectral consistency with Bennu and Ryugu, reinforcing their shared origin in the PEC. Minor absorptions in PEC asteroid spectra also connect to small bodies within and beyond the Main Belt, providing further evidence of outer Solar System formation for the PEC parent bodies.

astro-ph.EP↗

arXiv2026

JWST and Gemini Observations of the Active Centaur 450P/LONEOS: Nucleus and Coma Characterizations

Between 2019 and 2024, we used the Gemini-N and JWST observatories to conduct a detailed case study of the active Centaur 450P/LONEOS, whose orbit was significantly altered by a close Saturn encounter in 1992. Gemini-N GMOS optical images likely captured the first views of 450P's inactive nucleus, indicating a relatively small radius of $R_N = 1.8\pm0.5$ km and a surface color of $g' - i' = 1.15\pm0.09$. This places 450P on the red end of the neutral/gray Centaur population and may indicate comparatively limited solar-driven surface processing relative to other known active Centaurs. A coma developed as 450P changed its heliocentric distance, $R_H$, from 7.83 au to 7.24 au, with an estimated low dust production rate of $\sim$4-8 kg s$^{-1}$. JWST NIRSpec IFU Prism-mode spectra revealed an elongated dust morphology and a symmetric $CO_2$ gas distribution in the coma but no $H_2O$ or CO emission features, with production rates of $Q_{CO_2} = (6.99\pm0.07)\times10^{24}$ molec. s$^{-1}$, $Q_{H_2O} \leq 1.2\times10^{24}$ molec. s$^{-1}$, and $Q_{CO} \leq 5.2\times10^{24}$ molec. s$^{-1}$. Absorption features at 2.0 and 3.0 $\mu$m indicate the presence of water ice, and a subtle 3.1 $\mu$m feature is consistent with crystalline water ice in larger grains. A Hapke-style model dominated by large ($D_{eff.} = 5.9$ $\mu$m) dust grains with a volumetric ice fraction of $f_{ice} = 33\%$ fits the spectrum. A thermal model incorporating 450P's orbital history since $\sim$1500 CE aligns with the observed onset of activity driven by $CO_2$ outgassing from amorphous water ice crystallization between 140-160 K.

astro-ph.EP↗

arXiv2026

Accessible does not mean exploitable: HiPERCAM reveals the ultra-fast rotation of 2022 OB$_5$

2022 OB$_5$ is a sub-10-metre Apollo-type near-Earth asteroid whose orbital configuration placed it among the most dynamically accessible small bodies in near-Earth space, motivating its selection as the target of the first commercial asteroid-prospecting mission. We present its first photometric characterisation, based on high-cadence simultaneous five-band $u_sg_sr_si_sz_s$ observations obtained with HiPERCAM at the 10.4-m Gran Telescopio Canarias (GTC). Analysis of the light curves yields a rotation period of $P_{\rm rot} = 1.542 \pm 0.001$ min, independently confirmed with observations taken by the Two-meter Twin Telescope, establishing 2022 OB$_5$ as an ultra-fast rotator. The reflectance spectrum derived from the simultaneous multiband photometry is featureless and moderately red, consistent with the X-complex. Despite its good orbital accessibility, the ultra-fast rotation of 2022 OB$_5$ poses severe practical challenges for any surface operation with current technology, regardless of compositional interest. This illustrates a population-level challenge: at the sizes and $\Delta v$ values most favourable for in-situ missions, fast rotation is the dominant spin state, and rotation period measurement is therefore an indispensable prerequisite for evaluating the resource potential of asteroid mission candidates.

astro-ph.EP↗

arXiv2026

Spin Parameters and Shape Models of Near-Earth Asteroids (4660) Nereus, (21088) Chelyabinsk, (66146) 1998 TU3, and (297418) 2000 SP43

We present our shape and rotational characterization of four near-Earth asteroids observed as part of the Visible NEAs Observations Survey. This work includes 61 new light curves obtained between 2020 June and 2024 September for asteroids (21088) Chelyabinsk and (66146) 1998 TU3 and the potentially hazardous asteroids (4660) Nereus and (297418) 2000 SP43. We combine these observations with archival data to derive their shape models, spin parameters, and refined rotation periods using a light-curve inversion method. Our derived rotational periods are consistent with previously published values for all the objects. We present constant-period models for each asteroid, while for (66146) 1998 TU3 we detect a possible Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) acceleration of $\upsilon \simeq 2.05 \times 10^{-8} \text{ rad day}^{-2}$, potentially adding it to the short list of asteroids known to experience the YORP effect.

astro-ph.EP↗

arXiv2026

A dedicated survey of fast-rotating near-Earth asteroids with the Two-meter Twin Telescope. I. Observational strategy and first results

The rotational properties of small near-Earth asteroids (NEAs) provide crucial insights into their internal structure and collisional history. However, systematic surveys targeting metre- to decametre-sized bodies are rare, thus leaving their spin distribution poorly constrained. Our aim was to quantify the prevalence of fast rotation and characterise the spin-rate distribution of small NEAs to constrain their internal strength and evolution. We conducted a dedicated high-cadence photometric survey of 249 NEAs using the Two-meter Twin Telescope (TTT). Rotation periods and amplitudes were derived from dense time series to classify objects as fast or non-fast rotators. We determined the rotation period of 156 new fast rotators (P < 2.2 h), including 87 that rotate faster than 10 min. The prevalence of fast rotators increases with absolute magnitude: from 60.6-80.3 % for 22 < H < 24 to 77.3-89.4 % for 24 < H < 26 and 94.1-96.1 % for H > 26, indicating that fast rotation dominates in the small NEA population. Most objects spin faster than the gravity-defined limit; 98 targets require cohesive strengths exceeding that of weak rubble piles, and 22 are compatible only with compact, high-strength interiors. This is the first systematic survey targeting the rotation of such small NEAs, providing the largest homogeneous sample of fast rotators obtained by a single campaign. Our findings demonstrate that fast rotation is the norm for objects smaller than tens of metres, implying that modest cohesive strength is required to prevent their rotational disruption.

astro-ph.EP↗

arXiv2025

Compositional characterisation of asteroid (84) Klio with JWST

The analysis of the composition of primitive C$-$complex asteroids is essential to understand the distribution of volatiles in the Solar System since its formation. Primitive low-albedo families within the inner main asteroid belt are of particular interest because they are a significant source of carbonaceous near-Earth asteroids, such as Ryugu and Bennu. This study, part of the JWST SAMBA3 project (Spectral Analysis of Main Belt Asteroids in the 3 $\mu$m region), report the first spectroscopic analysis of asteroid (84) Klio in the 3 $\mu$m region, in order to better constrain its composition. We analysed the infrared (0.97$-$5.10 $\mu$m) Spectrum of Klio measured by the NIRSpec instrument on board JWST. We used the NEATM thermal model to extract the reflectance spectrum of the asteroid. Several spectral features were then analysed in the 2.8, 3.4, and 3.9 $\mu$m regions by different Gaussian fitting. The Spectrum of Klio shows an absorption band at 2.776 $\pm$ 0.001 $\mu$m that we attributed to phyllosilicates. We compared the position and shape of the feature with that observed in primitive materials such as carbonaceous chondrites and returned samples from Ryugu and Bennu. The position and shape of the 2.8 $\mu$m band, as well as the presence of a 0.7 $\mu$m band in the visible, suggest that Klio's spectrum is similar to certain CM2 meteorites. We observed an absorption band around 3.9 $\mu$m, with a depth of $0.020 \pm 0.001$ that could be attributed to carbonates. We could not clearly detect any absorption associated with organics at 3.4 $\mu$m.

astro-ph.EP↗

arXiv2025

ATLAS Photometry of Interstellar Object 3I/ATLAS

We present calibrated ATLAS photometry of the interstellar comet 3I/ATLAS (C/2025 N1) from 28 March through 29 Aug 2025, obtained with the five-site, robotic ATLAS network in the c (420-650~nm), o (560-820~nm), and Teide w (420-720~nm) bands. Stacked difference images yield reliable light curves measured in four fixed apertures that capture the evolving coma. We observe 3I/ATLAS transitioning in color from red (c-o)~0.7 before MJD 60860 to near-solar (c-o)~0.3 after MJD 60870, coincident with the appearance of a prominent anti-solar tail. The absolute magnitude curve H(t) shows a slope break near MJD 60890 at r~3.3 au from -0.035 to -0.012 mag/day, or in terms of coma cross section as a function of heliocentric distance, r^{-3.9} to r^{-1.1}.

astro-ph.EP↗

arXiv2025

Characterization of of (98943) 2001 CC$_{21}$, the target of Hayabusa2$\#$

The near-Earth asteroid (98943) Torifune, previously designated 2001 CC$_{21}$, is the flyby target of the Hayabusa2 extended mission, nicknamed Hayabusa2$\#$ (SHARP: Small Hazardous Asteroid Reconnaissance Probe). The ground-based telescope observations offer a key science input for the mission's scientific investigation. During 2022 - 2024 this asteroid was at visible apparent magnitudes brighter than 18.5, allowing for a detailed characterization using ground-based telescope observations. We determined its rotation period $P~=~5.021516\pm0.000106$ h and its absolute magnitude H = 18.78 $\pm$ 0.14 and. The large number of lightcurves allows to estimate its axes ratio, its convex shape and its pole orientation $\lambda = 301^{\circ} \pm 35^{\circ}$, $\beta = {89^{+1}_{-6}}^{\circ}$ and $\epsilon = 5^{\circ} \pm 3^{\circ}$ which indicate a prograde rotation. We report the semi-axis of the equivalent ellipsoid, $a$ = 0.42$^{+0.08}_{0.06}$ km, $b$ = 0.16$^{+0.05}_{0.04}$ km, and $c$ = $0.17\pm0.03$ km. Consequently, the volume equivalent diameter is $D_{eq}$ = $0.44 \pm 0.06$ km . Using observations conducted simultaneously with four broadband filters, we determined $(g-r) = 0.663 \pm 0.022$ mag, $(r-i) = 0.177 \pm 0.012$ mag, and $(i-z_s) = -0.061 \pm 0.032$ mag. Additionally, we found that Torifune exhibits no detectable large-scale heterogeneity. We classified the object using a high signal-to-noise ratio spectrum (over the visible and near-infrared region) as Sq-type in the Bus-DeMeo taxonomy. We estimate a mineralogy similar to LL/L ordinary chondrites, with an ol/(ol+px) = 0.60, a Fa content of 28.5 mol$\%$, and a Fs content of 23.4 mol$\%$. The spectral data indicate a surface affected by moderate space weathering effects.

astro-ph.EP↗

arXiv2024

Light-curve analysis and shape models of NEAs 7335, 7822, 154244 and 159402

In an attempt to further characterise the near-Earth asteroid (NEA) population we present 38 new light-curves acquired between September 2020 and November 2023 for NEAs (7335) 1989 JA, (7822) 1991 CS, (154244) 2002 KL6 and (159402) 1999 AP10, obtained from observations taken at the Teide Observatory (Tenerife, Spain). With these new observations along with archival data, we computed their first shape models and spin solutions by applying the light curve inversion method. The obtained rotation periods are in good agreement with those reported in previous works, with improved uncertainties. Additionally, besides the constant period models for (7335) 1989 JA, (7822) 1991 CS and (159402) 1999 AP10, our results for (154244) 2002 KL6 suggest that it could be affected by a Yarkovsky-O'Keefe-Radzievskii-Paddack acceleration with a value of $\upsilon \simeq -7 \times 10^{-9}$ rad d$^{-2}$. This would be one of the first detections of this effect slowing down an asteroid.

astro-ph.EP↗

arXiv2024

Pre-perihelion Monitoring of Interstellar Comet 2I/Borisov

The discovery of interstellar comet 2I/Borisov offered the unique opportunity to obtain a detailed analysis of an object coming from another planetary system, and leaving behind material in our interplanetary space. We continuously observed 2I/Borisov between October 3 and December 13, 2019 using the 1.52-m Telescopio Carlos S\'{a}nchez equipped with MuSCAT2 instrument, and the 2.54-m Isaac Newton Telescope with Wide Field Camera. We characterize its morphology and spectro-photometric features using the data gathered during this extended campaign. Simultaneous imaging in four bands ($g$, $r$, $i$, and $z_s$) reveals a homogeneous composition and a reddish hue, resembling Solar System comets, and as well a diffuse profile exhibiting familiar cometary traits. We discern a stationary trend fluctuating around a constant activity level throughout October and November 2019. Subsequently, a reduction in activity is observed in December. Dust production and mass loss calculations indicate approximately an average of 4 kg/s before perihelion, while after perihelion the net mass loss is about 0.6 kg/s. Our simulations indicate the most probable size of coma dust particles should be in the range 200-250 nm, and the terminal speed around 300 m/s. The spectrum acquired with the 4.2-m William Herschel Telescope shows the presence of a strong CN line for which we find a gas production rate of $1.2 \times 10^{24}~s^{-1}$. We also detected NH$_2$ and OI bands. The ratio between NH$_2$ and CN productions is $\log (NH_2/CN) =-0.2$. Overall, this observing campaign provides a new understanding of 2I/Borisov's unique characteristics and activity patterns.

astro-ph.EP↗

arXiv2023

Improved models for near-Earth asteroids (2100) Ra-Shalom, (3103) Eger, (12711) Tukmit & (161989) Cacus

We present 24 new dense lightcurves of the near-Earth asteroids (3103) Eger, (161989) Cacus, (2100) Ra-Shalom and (12711) Tukmit, obtained with the Instituto Astrof\'isico Canarias 80 and Telescopio Abierto Remoto 2 telescopes at the Teide Observatory (Tenerife, Spain) during 2021 and 2022, in the framework of projects visible NEAs observations survey and NEO Rapid Observation, Characterization and Key Simulations. The shape models and rotation state parameters ($P$, $\lambda$, $\beta$) were computed by applying the lightcurve inversion method to the new data altogether with the archival data. For (3013) Eger and (161989) Cacus, our shape models and rotation state parameters agree with previous works, though they have smaller uncertainties. For (2100) Ra-Shalom, our results also agree with previous studies. Still, we find that a Yarkovsky - O'Keefe - Radzievskii - Paddack acceleration of $\upsilon = (0.223\pm0.237)\times10^{-8}$ rad d$^{-2}$ slightly improves the fit of the lightcurves, suggesting that (2100) Ra-Shalom could be affected by this acceleration. We also present for the first time a shape model for (12711) Tukmit, along with its rotation state parameters ($P=3.484900 \pm 0.000031$ hr, $\lambda = 27^{\circ}\pm 8^{\circ}$, $\beta = 9^{\circ} \pm 15^{\circ}$).

astro-ph.EP↗

arXiv2023

Photometry of the Didymos system across the DART impact apparition

On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft impacted Dimorphos, the satellite of binary near-Earth asteroid (65803) Didymos. This demonstrated the efficacy of a kinetic impactor for planetary defense by changing the orbital period of Dimorphos by 33 minutes (Thomas et al. 2023). Measuring the period change relied heavily on a coordinated campaign of lightcurve photometry designed to detect mutual events (occultations and eclipses) as a direct probe of the satellite's orbital period. A total of 28 telescopes contributed 224 individual lightcurves during the impact apparition from July 2022 to February 2023. We focus here on decomposable lightcurves, i.e. those from which mutual events could be extracted. We describe our process of lightcurve decomposition and use that to release the full data set for future analysis. We leverage these data to place constraints on the post-impact evolution of ejecta. The measured depths of mutual events relative to models showed that the ejecta became optically thin within the first ~1 day after impact, and then faded with a decay time of about 25 days. The bulk magnitude of the system showed that ejecta no longer contributed measurable brightness enhancement after about 20 days post-impact. This bulk photometric behavior was not well represented by an HG photometric model. An HG1G2 model did fit the data well across a wide range of phase angles. Lastly, we note the presence of an ejecta tail through at least March 2023. Its persistence implied ongoing escape of ejecta from the system many months after DART impact.

astro-ph.EP↗

arXiv2023

Long-lasting activity of asteroid (248370) 2005 QN 173

We present the results of observations of asteroid (248370) QN$_{173}$ obtained during July 2021 - January 2022 with three telescopes. Our analysis revealed the presence of the dust tail for about half of a year. The direct images of the asteroid were obtained with broad-band filters. No emissions were revealed in the spectra, and the spectrum of the asteroid closely matched that of a C-type asteroid. Created color and linear polarization variations along the tail were analyzed. The asteroid demonstrated a redder color compared to the Sun. Dramatic changes in dust productivity obtained in different filters were not detected. The $g-r$ color changes from $0.2^{m}$ to $0.7^{m}$ over the coma, and the linear polarization degree varies from about $1.2$\% to $0.2$\% and from $-0.2$\% to $-1.5$\% at the phase angle of $23.2^{\circ}$ and $8.16^{\circ}$. The total dust mass ejected until the latest observation on October 10 is $4.2 \times 10^7$~kg, with a maximum rate of 2.6~kg\,s$^{-1}$ based on the Monte Carlo modeling of the dust tail. The estimated asteroid size is 1.3~km. It is shown that large particles are concentrated around the nucleus, whereas smaller ones dominate in the tail. The evolution of (248370) QN$_{173}$ orbit and the orbits of the sample of the 464 short-periodic comets were followed. Ten of them approached the asteroid's orbit. These objects are not genetically related, despite the very close distance of their orbits for a relatively long time.

astro-ph.EP↗

arXiv2023

Characterization of the ejecta from NASA/DART impact on Dimorphos: observations and Monte Carlo models

The NASA/DART (Double Asteroid Redirection Test) spacecraft successfully crashed on Dimorphos, the secondary component of the binary (65803) Didymos system. Following the impact, a large dust cloud was released, and a long-lasting dust tail was developed. We have extensively monitored the dust tail from the ground and from the Hubble Space Telescope (HST). We provide a characterization of the ejecta dust properties, i.e., particle size distribution and ejection speeds, ejection geometric parameters, and mass, by combining both observational data sets, and by using Monte Carlo models of the observed dust tail. The differential size distribution function that best fits the imaging data was a broken power-law, having a power index of --2.5 for particles of r$\le$ 3 mm, and of --3.7 for larger particles. The particles range in sizes from 1 $\mu$m up to 5 cm. The ejecta is characterized by two components, depending on velocity and ejection direction. The northern component of the double tail, observed since October 8th 2022, might be associated to a secondary ejection event from impacting debris on Didymos, although it is also possible that this feature results from the binary system dynamics alone. The lower limit to the total dust mass ejected is estimated at $\sim$6$\times$10$^6$ kg, half of this mass being ejected to interplanetary space.

astro-ph.EP↗

arXiv2023

Near-Ultraviolet Absorption Distribution of Primitive Asteroids from Spectrophotometric Surveys

Aims: Our objectives were first to evaluate the possibility for using the NUV absorption as diagnostics of hydrated minerals based on the recent datasets of primitive asteroids and hydrated carbonaceous chondrites, and second to investigate the reflectance spectrophotometry of the primitive asteroids in the NUV as functions of heliocentric distance and size. Methods: The NUV and visible reflectance spectrophotometry of more than 9,000 primitive asteroids was investigated using two spectrophotometric surveys, the Eight Color Asteroid Survey (ECAS) and the Sloan Digital Sky Survey (SDSS), which cover wavelengths down to 0.32 um and 0.36 um, respectively. We classified asteroids from the main asteroid belt, the Cybele and Hilda zones, and Jupiter Trojans based on Tholen's taxonomy and described the statistical distribution of primitive asteroid types. We also examined the relationship of the NUV, 0.7 um, and 2.7 um absorptions among primitive asteroids and hydrous carbonaceous chondrites CI and CM. Results: We found strong correlations between the NUV and the OH-band (2.7 um) absorptions for primitive asteroids and hydrated meteorites, suggesting the NUV absorption can be indicative of hydrated silicates. Moreover, there is a great difference in the NUV absorption between the large asteroids (diameter d > 50 km) and small asteroids (d < 10 km) in the taxonomic distribution. The taxonomic distribution of asteroids differs between the inner main belt and middle-outer main belt. Notably, the C types are dominating large members through the main belt and the F types are dominating small asteroids of the inner main belt. The asteroids beyond the main belt consist mostly of P and D types, although P types are common everywhere in the main belt. The peculiar distribution of F types might indicate a different formation reservoir or displacement process of F types in the early Solar System.

astro-ph.EP↗

arXiv2023

ATLAS-TEIDE: The next generations of ATLAS units for the Teide Observatory

In this work we present the design of the ATLAS unit (Asteroid Terrestrial-impact Last Alert System) that will be installed at Teide Observatory in Tenerife island (Spain). ATLAS-Teide will be built by the Instituto de Astrofisica de Canarias (IAC) and will be operated as part of the ATLAS network in the framework of an operation and science exploitation agreement between the IAC and the ATLAS team at University of Hawaii. ATLAS-Teide will be the first ATLAS unit based on commercial on the shelf (COTS) components. Its design is modular, each module (building block) consist of four Celestron RASA 11 telescopes that point to the same sky field, equipped with QHY600PRO CMOS cameras on an equatorial Direct Drive mount. Each module is equivalent to a 56cm effective diameter telescope and provides a 7.3 deg^2 field of view and a 1.26 arcsec/pix plate scale. ATLAS-Teide will consist of four ATLAS modules in a roll-off roof building. This configuration allows to cover the same sky area of the actual ATLAS telescopes. The first ATLAS module was installed in November 2022 in an existing clamshell at the TO. This module (ATLAS-P) is being used as a prototype to test the system capabilities, develop the needed software (control, image processing, etc.) and complete the fully integration of ATLAS-Teide in the ATLAS network. The preliminary results of the tests are presented here, and the benefits of the new ATLAS design are discussed.

astro-ph.IM↗

arXiv2023

Scientific CMOS sensors in Astronomy: IMX455 and IMX411

Scientific complementary metal-oxide-semiconductor (CMOS) detectors have developed quickly in recent years thanks to their low cost and high availability. They also have some advantages over charge-coupled devices (CCDs), such as high frame rate or typically lower readout noise. These sensors started to be used in astronomy following the development of the first back-illuminated models. Therefore, it is worth studying their characteristics, advantages, and weaknesses. One of the most widespread CMOS sensors are those from the Sony IMX series, which are included in large astronomical survey projects based on small and fast telescopes because of their low cost, and capability for wide-field and high-cadence surveys. In this paper, we aim to characterize the IMX455M and IMX411M sensors, which are integrated into the QHY600 and QHY411 cameras, respectively, for use in astronomical observations. These are large (36 $\times$ 24 and 54 $\times$ 40 mm) native 16 bit sensors with 3.76 $\mu$m pixels and are sensitive in the optical range. We present the results of the laboratory characterization of both cameras. They showed a very low dark current of 0.011 and 0.007 e$^{-}$ px$^{-1}$ s$^{-1}$ @$-$10 C for the QHY600 and QHY411 cameras, respectively. They also show the presence of warm pixels, $\sim$0.024% in the QHY600 and 0.005% in the QHY411. Warm pixels proved to be stable and linear with exposure time, and are therefore easily corrected using dark frames. Pixels affected by the Salt \& Pepper noise are $\sim$2% of the total and a method to correct for this effect is presented. Both cameras were attached to night telescopes and several on-sky tests were performed to prove their capabilities. On-sky tests demonstrate that these CMOS behave as well as CCDs of similar characteristics and (for example) they can attain photometric accuracies of a few milli-magnitudes.

astro-ph.IM↗