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 Gemini Multi-Object Spectrograph optical images likely captured the first views of 450P's inactive nucleus, indicating a relatively small radius of RN = 1.8 +/- 0.5 km and a surface color of g '-i ' = 1.15 +/- 0.09. 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, RH, from 7.83 to 7.24 au, with an estimated low dust production rate of similar to 4-8 kg s-1. JWST NIRSpec integral field unit prism-mode spectra revealed an elongated dust morphology and a symmetric CO2 gas distribution in the coma but no H2O or CO emission features, with production rates of QCO2 = (6.99 +/- 0.07) & times; 1024 molecules s-1, QH2O <= 1.2 & times; 1024 molecules s-1, and QCO <= 5.2 & times; 1024 molecules 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, which is consistent with crystalline water ice in larger grains. A Hapke-style model dominated by large (Deff = 5.9 mu m) dust grains with a volumetric ice fraction of fice = 33% fits the spectrum. A thermal model incorporating 450P's orbital history since similar to 1500 CE aligns with the observed onset of activity driven by CO2 outgassing from amorphous water ice crystallization between 140 and 160 K.

We report on the observation and measurement of astrometry, photometry, morphology, and activity of the interstellar object 3I/ATLAS, also designated C/2025 N1 (ATLAS) with the NSF-DOE Vera C. Rubin Observatory. Comet 3I/ATLAS, the third known interstellar object, was discovered on UT 2025 July 1. Rubin Observatory had coincidentally collected images of the object's region of the sky during routine commissioning. Facilitated by Rubin's high resolution and large aperture, we successfully recovered object detections from Rubin observations spanning UT 2025 June 21 (10 days before discovery, when 3I/ATLAS was 4.5 au from the Sun) through the date of discovery, and we acquired additional images through UT 2025 July 20 as part of commissioning. We measure on-sky locations of 3I/ATLAS in Rubin ugrizy bands, with a typical precision of similar to 70 mas, and briefly describe the reason this is coarser than our measured static source astrometric precision of similar to 3 mas in Rubin images. We measure grizy magnitudes of 3I/ATLAS photometry at similar to 0.01 mag precision, detecting no short-term photometric variability above 0.01 mag. We derive an estimated near-nucleus dust-to-nucleus scattering cross-sectional ratio of eta greater than or similar to 13 on UT 2025 July 2 based on Rubin photometry and an upper limit nucleus size computed from Hubble Space Telescope observations. We find Rubin colors of g - r = (0.657 +/- 0.013) mag, r - i = (0.235 +/- 0.018) mag, i - z = (0.147 +/- 0.042) mag, and z - y = (0.047 +/- 0.052) mag. These data represent the earliest observations of this object by a large (greater than or similar to 8 m class) telescope and illustrate the type of measurements (and discoveries) Rubin's Legacy Survey of Space and Time will provide after it begins in early 2026.

Hyperactive comet activity typically becomes evident beyond the frost line (3 to 4 au) where it becomes too cold for water-ice to sublimate. If carbon monoxide (CO) and carbon dioxide (CO2) are the species that drive activity at sufficiently large distances, then detailed studies on the production rates of these species are extremely valuable to examine the formation of the solar system because these two species (beyond water) are next culpable for driving cometary activity. The NEOWISE reactivated mission operates at two imaging bandpasses, W1 and W2 at 3.4 and 4.6 microns, respectively, with the W2 channel being fully capable of detecting CO and CO2 at 4.67 and 4.23 microns in the same bandpass. It is extremely difficult to study CO2 from the ground due to contamination in Earth's atmosphere. We present our W1 and W2 photometry, dust measurements, and findings for comets C/2014 B1 (Schwartz), C/2017 K2 (Pan-STARRS), and C/2010 U3 (Boattini), hereafter, B1, K2, and U3, respectively. Our results assess CO and CO2 gas production rates observed by NEOWISE. We have determined: (1) comets B1 and K2 have CO2 and CO gas production rates of 1e27 and 1e29 molecules per second, respectively, if one assumes the excess emission is attributed to either all CO or all CO2; (2) B1 and K2 are considered hyperactive in that their measured AfRho dust production values are on the order of greater than or equal to 1e3 cm; and (3) the CO and CO2 production rates do not always follow the expected convention of increasing with decreased heliocentric distance, while B1 and K2 exhibit noticeable dust activity on their inbound leg orbits.

AbstractThe Near-Earth Object Surveillance Mission (NEOSM) will provide unprecedented detection, tracking and characterization of Near-Earth Objects (NEOs) using high-cadence imaging from a space-based infrared telescope. Planning for the NEOSM requires an accurate model of the solar system’s small body populations in order to develop efficient operational survey strategies and to assess survey performance once in-flight operations have commenced. The NEOSM Investigation Team is currently developing the Reference Small Body Population Model (RSBPM; [1]) that will contain the current best estimates of the dynamical and physical properties of the solar system’s small body populations. Development of the RSBPM will be completed before the NEOSM launch, and the finished product will be peer-reviewed to ensure accuracy. Once the survey begins, we will compare predictions based on the RSBPM to actual observational measurements to calculate the efficiency of the survey, and thus de-bias the survey to properly characterize each population in order to assess Earth impact risks. We present here an update to the methods of incorporating comets into the RSBPM, with particular focus on accurately incorporating dust and CO+CO2 gas comae activity behaviors. A better understanding of these physical characteristics are relevant for planetary defense (e.g., determining nuclei diameters).The high abundance of volatile ices (e.g., H2O, CO, CO2) present in comet nuclei drives outgassing and dust lofting when the surface material is exposed to the Sun, generating comae and tails. While high-cadence and long-baseline observational campaigns producing physical characterization of nuclei and comae exist for a few comets (e.g. 1P/Halley, 9P/Tempel, 67P/Churyumov-Gerasimenko, C/1995 O1 (Hale-Bopp), C/2012 S1 (ISON)) and have allowed determination of single-apparition secular light curves, predictions for the behaviors of an individual comet are notoriously difficult due to the possibility of outbursts, fragmentation events, complete nucleus disintegration and seasonal effects. This high degree of uncertainty for cometary behaviors introduces complications for modeling the brightening trends for individual comets as compared to those for the asteroid populations. Fortunately, characterizing the behaviors of comets in the infrared as an ensemble population is a somewhat more tractable problem. Previous (e.g., COBE [2], AKARI [3], Spitzer [4]) and ongoing surveys (e.g, Pan-STARRS [5], Zwicky Transient Facility [6], ATLAS [7], WISE/NEOWISE [8]) detecting large numbers of comets in the infrared are allowing a framework through which an individual comet’s activity behaviors can be estimated based on behavior trends in infrared emission of the larger ensemble. We are utilizing derived ensemble properties from these observational campaigns to develop a recipe for best simulating the morphological and photometric behaviors for the solar system’s comet populations.NEOSM will utilize a space-based 50-cm aperture infrared-optimized telescope located at the Sun-Earth L1 Lagrange position. It will contain a single instrument with a dual-channel infrared imaging camera that will survey the sky in bandpasses at 4-5.2 microns (denoted NC1) and 6-10 microns (denoted NC2). NC1 images of comets will mostly contain thermal emission (for comets within ~3 au of the Sun) from the nucleus and any dust coma/tail/trail. Additionally, the bandpass of NC1 covers the CO2 gas ν3 vibrational mode emission band centered at 4.26 microns and the CO gas vibrational mode emission band centered at 4.67 microns, which will allow detection of a comet’s combined CO+CO2 gas coma. This method of detecting such cometary volatiles via broadband imaging has had much success in the past with Spitzer (e.g. [4, 9]) and WISE/NEOWISE (e.g. [10, 11]). The longer wavelength NC2 images of comets will measure thermal emission from nuclei and dust. Because of the particular bandpasses of NC1 and NC2 we are currently focusing on developing methods of modeling cometary activity behaviors utilizing derived (1) nuclei cumulative size distributions, (2) dust activity behaviors as characterized by empirical trends of the εfρ parameter and (3) CO and CO2 gas comae trends based on the previously mentioned past and ongoing surveys. Future efforts by the NEOSM Investigation Team will focus on incorporation of other characteristic cometary phenomena (e.g., dust tails and trails) to help refine expected detection efficiencies and coma and/or tail flux removal for robust nucleus size estimation.AcknowledgementsNEOSM is a project sponsored by NASA’s Planetary Defense Coordination Office, a division of NASA’s Planetary Science Directorate.References[1] Lilly (Schunova) et al., 2020, AAS Meeting Abstracts, 385.04.[2] Lisse et al., 2002, IAU Colloq. 181, Vol. 15, 259.[3] Ootsubo et al., 2012, ApJ, 752:15.[4] Fernandez et al., 2013, Icarus, 226, Issue 1.[5] Denneau et al., 2013, PASP, 125:926.[6] Masci et al., 2019, PASP, 131:995.[7] Tonry et al., 2018, PASP, 130:988.[8] Mainzer et al., 2011, ApJ, 731:53.[9] Kelley et al., 2013, Icarus, 225:475.[10] Bauer et al., 2015, ApJ, 814:85.[11] Bauer et al., 2017, AJ, 154:53.

The active Centaur 29P/Schwassmann-Wachmann 1 has been an enigma since its discovery almost a century ago due to the combination of its orbital properties and outburst prone cometary behaviors. Its nearly circular trans-Jovian orbit (perihelion distance q ~ 5.8 au) provides a relatively stable thermal environment, yet 29P displays a moderately variable persistent dust and gas production sprinkled with frequent short-lived major outbursts when its visual magnitude brightens by ~ 1 to 6 magnitudes. This type of dust production behavior has been well documented since its discovery and it is unique. It is natural to then question whether 29P nucleus’ compositional nature is also unique, or whether its behaviors are explained by a fortuitous combination of orbital and nuclear properties (i.e., size, spin state, shape, etc.) such that 29P represents an extreme case of cometary activity that other objects would similarly display provided the right circumstances.We present the first NIR nucleus surface reflectance spectrum of 29P with the goal of using it to better explain its activity behaviors. Acquiring nucleus surface information for 29P is challenging due to the persistent presence of a dust coma which confuses attempts to disentangle nucleus vs. coma flux. The new spectrum we present was enabled by the combination of the wavelength coverage, sensitivity, and stable point spread function (PSF) of the JWST NIRSpec utilized in the integral field unit (IFU) mode. The spectral data were acquired with the PRISM disperser, covering a wavelength range of 0.6 – 5.3 microns, on UT 2023 February 20 as part of the Cycle 1 GO Program 2416 [1]. The IFU’s 3” x 3” field of view enabled application coma modeling and removal [2] to isolate the nucleus’ flux contributions over each of the datacube’s wavelengths to produce a nucleus-only reflectance spectrum.The NIR spectrum of 29P presents a shape retaining distinct characteristics of the “Bowl”-type trans-Neptunian Objects (TNOs) spectral classification established by the JWST Cycle 1 Program 2418 [2; DiSCo-TNOs]. TNOs from this population are hypothesized to have abundant water ice and to have formed interior to the CO2 ice line [4, 5]. The prospects of 29P’s progenitor nucleus forming in a region too warm for the condensation of CO and CO2, yet the gas comae environment observed with an abundance of both [6, 7] provides potential evidence of its nucleus having retained abundant amorphous water ice (AWI) trapping the two gas species. However, future studies are necessary to better understand the surface evolution experienced by Centaurs as they become thermally activated, potentially causing objects to change between spectral classification types, and trace the possible evolution of active surface areas. In our presentation we will show the surface reflectance spectrum and preliminary compositional modeling of the surface and thermophysical modeling of the nucleus’s bulk interior.References: [1] McKay, A., et al., JWST Proposal Cycle 1, ID. #2416. [2] Fernández, Y, R., et al., 2013, Icarus, 226, 1138-1170. [3] Pinilla-Alonso, N., et al., JWST Proposal. Cycle 1, ID. #2418. [4] Pinilla-Alonso, N., et al., Nature Astronomy, in review. [5] De Prá, M., et al., 2024, Nature Astronomy, in press. [6] Bockelée-Morvan, D., et al., 2022, A&A, 664, id.A95. [7] Faggi, S., et al., Nature Astronomy, in review.

The Double Asteroid Redirection Test (DART) spacecraft successfully impacted Dimorphos, the moon of the Didymos double-asteroid system, on 26 September 2022. The resulting data sets collected and relayed to Earth from DART and its companion Light Italian Cubesat for Imaging of Asteroids (LICIACube), as well as observations from four ground-based observatories following the impact and its aftermath, have been archived with the Small Bodies Node of the Planetary Data System. In anticipation of the October 2024 launch of the ESA mission Hera, set to investigate the aftermath of the DART collision in detail, we provide an overview and guide to the data legacy the DART mission has bequeathed to its successor.

The NEOWISE mission utilizes the Wide-Field Infrared Survey Explorer (WISE) spacecraft to detect and characterize Near-Earth Objects (NEOs) (Wright et al. 2010). The prime WISE mission was part of NASA’s Explorer Program, with the goal to map the entire sky using an infrared telescope with four infrared wavelength bands (3.4, 4.6, 12, and 22 mm). In December 2013, the WISE spacecraft was re-activated with two infrared wavelength bands W1 and W2 (respectively at 3.4 and 4.6 mm) to continue its search for NEOs under the NEOWISE program (Mainzer et al. 2014) as a NASA Planetary Defense asset. As the NEOWISE mission continued to take images, over 270 active comets were observed during the NEOWISE mission phase. The mission has also discovered 24 comets during the reactivation phase from 2013 to the present, 45 comets overall (including all phases starting from December, 2009), including comet C/2020 F3 (NEOWISE). This is a long-period comet having an orbital semi-major axis of 270 AU (Inbound) and 358 AU (Outbound), with eccentricity = 0.9992, and an Inclination of 129°. This comet was discovered on 2020 March 27 by NEOWISE. One of the advantages of the NEOWISE data is that we can constrain CO+CO2 production in comets, while ground-based observations do not provide signals detecting especially CO2 due to the Earth's atmospheric effect. In this study, we describe four visits of comet C/2020 F3 observed by NEOWISE in 2020-2021 and provide analyses of the CO+CO2 production rates indicating the coma gas activity of the comet at heliocentric distances Rh > 3 au. Since NEOWISE is a survey mission that samples the sky at near-90° solar elongations, we revisited the data collected when the NEOWISE survey covered the region of the sky where Comet C/2020 F3 was predicted to be located. The four visits that we analyzed were observed on 2020 Jan 17 (visit A), 2020 Mar 28 (visit B), 2021 Mar 01 (visit C), and 2021 Jul 13 (visit D). We mainly use the 4.6 mm W2 signals to constrain the CO+CO2 production rate because the presence of the strong gas (CO+CO2) emission is noticeable in the 4.6 mm wavelength bandpass; the W1 band (3.4 mm bandpass) is mostly dominated by dust signal. We follow the CO+CO2 extraction routine that has been used for calibrating a few hundred comets observed by NEOWISE (Bauer et al., 2015; 2017, Gicquel et al., 2023). Figure 1 NEOWISE observations of comet C/2020 F3 at 3.1 au (Visit A), 2.1 au (Visit B), 4.0 au (Visit C), and 4.9 au (Visit D). Given the uncertainty, visit B (Rh = 2.1 AU) and visit C (Rh = 4.0 AU) show more significant signals in both W1 and W2 bands than the other two visits. We found that CO+CO2 production rates of Comet C/2020F3 were 8.7 [0.24] E+26 and 2.6 [0.3] E+26 mol s-1 for visit B and C, respectively, while visits A and D had no detection. The measured gas rates yielded a comparable rate consistent with the preliminary result for the detected SPCs and LPCs, primarily observed in 2013-2015, a heliocentric distance between 2 to 4 AU (Bauer et al., 2021). If CO2 emission dominated W2 flux, this result supports that CO2 could be a strong contributor to inducing comet activity at relatively large heliocentric distances. We also employed a nucleus extraction technique (Bauer et al. 2017) to separate the coma and nucleus signals and constrained the size of the nucleus. We will present an analysis of the maximum active area on the nucleus corresponding to each measured gas species at the time of the comet’s discovery. As a final note, the existing numerical model used for the CO+CO2 extraction routine was developed in IDL. The revised implementation used in the current work has been translated to a more user-friendly interface written in Python, and can be adapted for similar analysis using the NEO Surveyor (NEOS) mission’s data (Mainzer et al. 2023) in the future. References Bauer, J. M., Stevenson, R., Kramer, E., et al. 2015, The Astrophysical Journal, 814, 85. Bauer, J. M., Grav, T., Ferna´ndez, Y. R., et al. 2017, The Astronomical Journal, 154, 53. Bauer, J. M., Gicquel, A., Kramer, E., & Meech, K. J. 2021, The Planetary Science Journal, 2, 34. Gicquel, A., Bauer, J. M., Kramer, E. A., Mainzer, A. K., & Masiero, J. R. 2023, The Planetary Science Journal, 4, 3. Mainzer, A., Bauer, J., Grav, T., et al. 2014, The Astrophysical Journal, 784, 110. Mainzer A.K., Masiero J.R., Abell P.A., Bauer J.M., Bottke W., Buratti B.J., Carey S.J., et al., 2023, PSJ, 4, 224. Wright, E. L., Eisenhardt, P. R., Mainzer, A. K., et al. 2010, The Astronomical Journal, 140, 1868.

The Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx), is a cosmological mission in NASA's Medium Explorer (MIDEX) astrophysics program that will launch in early 2025 and perform a 2-year all-sky near-infrared spectral survey [1-3]. (More details concerning SPHEREx are available at http://spherex.caltech.edu.)The upcoming SPHEREx spectral survey provides a fantastic opportunity to detect, spectrally categorize, and catalog hundreds of thousands of solar system objects at WISE/NEOWISE sensitivity levels in 102 spectral bands between 0.75 - 5.0 µm with R = 41 to 135 [4] using a single stable, well-characterized and calibrated space-based remote sensing platform [1-3]. Utilizing a sun-synchronous NEOWISE-like polar orbit, objects in the sky at ~90 deg elongation will be observed in each great circle. The Earth’s motion around the Sun advances the great circle’s longitude ~1 deg/day; taking data in both the leading/trailing directions so the entire sky’s range of longitudes is covered in 6 months.In this work we give an overview of the SPHEREx mission, and describe the promise and challenges of taking the SPHEREx sky-survey LVF imaging data obtained by a mission designed to study billions of fixed galaxies and produce a moving object catalog with scientific content even greater than of the previous NEOWISE NIR photometric all-sky catalog, for ~15 times less cost. The resulting spectra could be used for everything from discerning new families of asteroids, comets, Trojans, Centaurs, and KBOs; to characterizing brand new interstellar objects; to mapping the zodiacal light with higher spatial resolution than has ever been done previously while searching for compositional structures; and to augmenting the science return from missions like DAWN, Psyche, Lucy, and NEO Surveyor [5]. In addition, there is great potential for overlapping synergies with results from missions running concurrently in the late 2020’s like JWST, WFIRST, Euclid, GAIA, TESS, eROSITA and LSST [3,7]. The SPHEREx Solar System pipeline will rely on a “forced photometry” approach, extracting signal for known bodies at their predicted locations on the sky, and thus benefit from the observations obtained from these and other platforms. With great care of converting the millions of individual SPHEREx LVF sky images into calibrated spectra with observational systematics, the resultant data will be capable of: Determination of the size, albedo, and composition of ~105 asteroids [6, 7]. Discovery of newly active asteroids and characterization of known episodically active asteroids and Potentially Hazardous Objects [6, 8]. Characterization from 0.7-5.0 µm of Interstellar Objects passing through the SPHEREx sky survey from a stable, sensitive, above-the-atmosphere observatory. Spectral monitoring of the weather on Uranus, Nep- tune, and Pluto over weeks and years. Discovery, detection, and characterization of 1000’s of Centaurs and Comets, leading to better understanding of the origins and evolution of their primordial icy materials (especially CO2 which is unavailable from the ground), as well as support of the ESA Comet Interceptor Providing the planetary science community with an accurate object spectral data catalog containing ~105 objects with IRTF/SpeX/Prism-like data will require the work of a dedicated team familiar with the SPHEREx mission, instrument calibration, and science data pipeline, time domain astronomical observations, and big dataset archiving at the PDS and IRSA. References 1. Crill+ 2020, "SPHEREx: NASA's Near-IR Spectrophoto- metric All-Sky Survey", SPIE 11443, 114430I2. Doré+ 2016, “Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar & Planetary Science”, eprint arXiv:1606.070393. Doré+ 2018, “Science Impacts of the SPHEREx All-Sky Optical to Near-IR Spectral Survey II: Report of a Community Workshop on the Scientific Synergies Between the SPHEREx Survey & Other Astronomy Observatories”, eprint arXiv:1805.054894. Mainzer+ 2015, "Space-Based Infrared Discovery and Characterization of Minor Planets with NEOWISE", in Hand- book of Cosmic Hazards and Planetary Defense, ISBN: 978-3- 319-03952-7. pp. 583-6115. Mainzer+ 2023, PSJ 4, 224.6. Lisse & Bauer, 2023, “Planetary Defense Use of the SPHEREx Solar System Object Catalog”, PDO White Paper submitted August 2023, arxiv7. Ivezić+ 2019, "LSST: From Science Drivers to Reference Design and Anticipated Data Products", Astrophys J 873, 1118. Ivezic, Z. et al. 2022, "Simulated SPHEREx Spectra of Asteroids and Their Implications for Asteroid Size and Reflectance Estimation", Icarus 371, 11469

The upcoming NASA SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) all-sky 0.7 to 5.0 um spectral survey, to be conducted from 2025 to 2027, provides a unique space-based opportunity to detect, spectrally categorize, and catalog hundreds of thousands of solar system objects at WISE/NEOWISE sensitivities. This paper discusses the unique near-infrared capabilities of SPHEREx, its potential applications in Planetary Defense, (PD), and the implications for risk mitigation associated with Potentially Hazardous Objects (PHOs). By leveraging SPHEREx data, scientists and decision-makers can enhance our ability to track and characterize PHOs, ultimately contributing to the protection of our planet.

Centaurs are minor solar system bodies with orbits transitioning between those of trans-Neptunian scattered disk objects and Jupiter-family comets (JFCs). 39P/Oterma (39P) is a frequently active centaur that has recently held both centaur and JFC classifications and was observed with the JWST NIRSpec instrument on 2022 July 27 UTC while it was 5.82 au from the Sun. For the first time, CO 2 gas emission was detected in a centaur, with a production rate of Q CO 2 = (5.96 ± 0.80) × 10 23 molecules s −1 . This is the lowest detection of CO 2 of any centaur or comet. CO and H 2 O were not detected down to constraining upper limits. Derived mixing ratios of Q CO / Q CO 2 ≤ 2.03 and Q CO 2 / Q H 2 O ≥ 0.60 are consistent with CO 2 and/or CO outgassing playing large roles in driving the activity, but not water, and show a significant difference between the coma abundances of 29P/Schwassmann–Wachmann 1, another centaur at a similar heliocentric distance, which may be explained by thermal processing of 39P’s surface during its previous JFC orbit. To help contextualize the JWST data we also acquired visible CCD imaging data on two dates in 2022 July (Gemini-North) and September (Lowell Discovery Telescope). Image analysis and photometry based on these data are consistent with a point-source detection and an estimated effective nucleus radius of 39P in the range of R nuc = 2.21–2.49 km.

Hazards due to near-Earth objects (NEOs) continue to pose a threat to life on Earth. While our capability for discovering NEOs has steadily progressed over the last three decades, physical characterization of a representative population has lagged behind. To test the operational readiness of the global planetary defense capabilities, we conducted a community-led global planetary defense exercise, with support from the NASA's Planetary Defense Coordination Office (PDCO) and the International Asteroid Warning Network (IAWN), to test the operational readiness of global planetary defense capabilities. This campaign focused on the characterization (direct imaging, radar, spectroscopy) of the binary near-Earth asteroid (NEA) (66391) Moshup (formerly known as 1999 KW4) and its moon Squannit. We chose a binary system because roughly one in six large NEAs are binaries. An additional goal was to apply lessons learned from this campaign towards ground-based characterization campaign for binary NEA (65803) Didymos, the target of the PDCO's Double Asteroid Redirection Test (DART) and the European Space Agency's Hera missions. Spectral observations of Moshup from the NASA Infrared Telescope Facility (IRTF) show similarities to Q-type asteroids. Based on its spectral band parameters, the best meteorite analogs for Moshup are L chondrites. We did not detect a hydration feature at 3 mu m, which suggests that the entire surface is anhydrous. We imaged the binary using the SPHERE instrument on the Very Large Telescope (VLT) and obtained resolved spectral measurements of Moshup similar to those obtained with the NASA IRTF. Squannit appears to have slightly redder spectral slope than Moshup. Radar observations Arecibo Observatory at 2380 MHz indicate a polarization ratio of ~0.4, which is higher than the average values for the S complex asteroids, which includes Q types. The visible extent of the components from the radar observations, taken as proxies for their radii, suggest Moshup and Squannit have diameters of 1500 +/- 120 m and 480 +/- 60 m, respectively. We constrain the system mass to 2.2 +/- 0.5 x 10(12) kg with a maximum range for bulk density between ~0.8 g/cm(3) for a very low-mass system with spherical shapes up to 2.7 g/cm(3) for very high-mass system where Moshup has a more ridged-ball shape. We note that the radar-derived parameters presented in the paper are for the purposes of this exercise and do not supersede those in Ostro et al. (2006). We assessed the impact risk of a hypothetical impactor based on Moshup's physical properties using the Probabilistic Asteroid Impact Risk (PAIR) model. We assessed three impact risk scenarios at different epochs as the state of knowledge of Moshup improved. For kilometer-scale impactors like Moshup, the risk is driven predominantly by the potential for global climatic effects (95-97% of cases across the epochs) with a few percent driven by local damage and a few tenths of a percent driven by tsunami.

Assess the joint capabilities of emerging telescopes for near-Earth objects (NEOs) survey and characterization, and what they will add to the current capabilities or replace. NASA telescopes in prime mission, in development, or under study, and requested for this assessment, include: - The Transiting Exoplanet Survey Satellite (TESS) - The James Webb Space Telescope (JWST) - The Wide Field Infrared Survey Telescope (WFIRST) - The Near-Earth Object Camera (NEOCam). Also requested for this assessment is the Large Synoptic Survey Telescope (LSST), an 8.4-meter ground-based telescope in development by the National Science Foundation and Department of Energy (DOE), with the capability to discover and catalogue NEOs.

46 / Bull. Kor. Astron. Soc. Vol. 45 No.1, Oct. 2020 images. These images were taken on 2005 November 12 during the close approach to the asteroid. As a result, we found the surface exposure timescales of these boulders are an order of 106 years. In this meeting, we will introduce our data analysis technique and evaluate the consistency among previous research for a better understanding of the evolution of this near-Earth asteroid.

We present visible and mid-infrared imagery and photometry of temporary Jovian co-orbital comet P/2019 LD2 taken with Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3), Spitzer Space Telescope/Infrared Array Camera (Spitzer/IRAC), and the GROWTH telescope network, visible spectroscopy from Keck/Low-Resolution Imaging Spectrometer (LRIS), and archival Zwicky Transient Facility observations taken between 2019 April and 2020 August. Our observations indicate that the nucleus of LD2 has a radius between 0.2 and 1.8 km assuming a 0.08 albedo and a coma dominated by ∼100 μm-scale dust ejected at ∼1 m s−1 speeds with a ∼1′ jet pointing in the southwest direction. LD2 experienced a total dust mass loss of ∼108 kg at a loss rate of ∼6 kg s−1 with Afρ/cross section varying between ∼85 cm/125 km2 and ∼200 cm/310 km2 from 2019 April 9 to 2019 November 8. If the increase in Afρ/cross section remained constant, it implies LD2's activity began ∼2018 November when within 4.8 au of the Sun, implying the onset of H2O sublimation. We measure CO/CO2 gas production of ≲1027 mol s−1/≲1026 mol s−1 from our 4.5 μm Spitzer observations; g–r = 0.59 ± 0.03, r–i = 0.18 ± 0.05, and i–z = 0.01 ± 0.07 from GROWTH observations; and H2O gas production of ≲80 kg s−1 scaling from our estimated C2 production of mol s−1 from Keck/LRIS spectroscopy. We determine that the long-term orbit of LD2 is similar to Jupiter-family comets having close encounters with Jupiter within ∼0.5 Hill radius in the last ∼3 y and within 0.8 Hill radius in ∼9 y. Additionally, 78.8% of our orbital clones are ejected from the solar system within 1 × 106 yr, having a dynamical half-life of 3.4 × 105 yr.

We present visible and mid-infrared imagery and photometry of Jovian co-orbital comet P/2019 LD₂ (ATLAS) taken with Hubble Space Telescope/WFC3 on 2020 April 1, Spitzer Space Telescope/IRAC on 2020 January 25, Zwicky Transient Facility between 2019 April 9 and 2019 Nov 8 and the GROWTH telescope network from 2020 May to July, as well as visible spectroscopy from Keck/LRIS on 2020 August 19. Our observations indicate that LD₂ has a nucleus with radius 0.2-1.8 km assuming a 0.08 albedo and that the coma is dominated by ∼100 μ m-scale dust ejected at m/s speeds with a ∼1 jet pointing in the SW direction. LD₂ experienced a total dust mass loss of ∼10⁸ kg and dust mass loss rate of ∼6 kg/s with Afρ/cross-section varying between ∼85 cm/125 km² and ∼200 cm/310 km² between 2019 April 9 and 2019 Nov 8. If the Afρ/cross-section increase remained constant, it implies that LD₂ has remained active since ∼2018 November when it came within 4.8 au of the Sun, a typical distance for comets to begin sublimation of H₂O. From our 4.5 μm Spitzer observations, we set a limit on CO/CO₂ gas production of ∼10²⁷/∼10²⁶ mol/s. Multiple bandpass photometry of LD₂ taken by the GROWTH network measured in a 10,000 km aperture provide color measurements of g-r = 0.59±0.03, r-i = 0.18±0.05, and i-z = 0.01±0.07, colors typical of comets. We set a spectroscopic upper limit to the production of H₂O gas of ∼80 kg/s. Improving the orbital solution for LD₂ with our observations, we determine that the long-term orbit of LD₂ is that of a typical Jupiter Family Comet having close encounters with Jupiter coming within ∼0.5 Hill radius in the last ∼3 y to within 0.8 Hill radius in ∼9 y and has a 95% chance of being ejected from the Solar System in < 10 Myr.