The Hayabusa2 & sharp; flyby target 98943 Torifune (2001 CC21) has an uncertain size based on an uncertain albedo and absolute magnitude. We have collected all the NEOWISE observations of 2001 CC21 from 2021 November through 2024 February, a total of 132 frames, and analyzed these data to estimate an infrared radiometric diameter. We analyze the multiepoch 3.4 and 4.6 mu m NEOWISE data using an ellipsoidal, rotating, cratered thermophysical model (TPM) to obtain estimates for the diameter, rotation pole, shape, and thermal inertia. 2001 CC21 is quite faint at 4.6 mu m when Delta similar to 0.7 au, so the resulting diameter is substantially smaller than the 700 m derived from the H magnitude and L spectral type. Recent polarimetric data have also suggested a smaller diameter, but not quite as small as the diameter derived from the thermal IR data. A fit to an ellipsoidal TPM model gives a volume-equivalent sphere diameter of 337-27+33 m (posterior median and central 68% confidence interval). Prograde rotation with an obliquity of (24-9+6)degrees is preferred. We also applied this TPM to the Spitzer data presented by S. Fornasier et al. and obtained a diameter of 476% +/- 9% m, which is consistent with the NEATM modeling presented by Fornasier et al. but with more realistic error bars. Finally, fitting the NEOWISE and Spitzer data together requires unexpectedly large thermal inertias and gives a bimodal posterior diameter distribution.

Near-Earth asteroids are of great interest to the scientific community due to their proximity to Earth, making them both potential hazards and possible targets for future missions, as they are relatively easy to reach by spacecraft. A number of techniques and models can be used to constrain their physical parameters and build a comprehensive assessment of these objects. In this work, we compare physical property results obtained from improved H _V absolute magnitude values, thermophysical modeling, and polarimetry data for the well-known Amor-class NEO 1627 Ivar. We show that our fits for albedo are consistent with each other, thus demonstrating the validity of this cross-referencing approach, and propose a value for Ivar's albedo of $0.2{4}_{-0.02}^{+0.04}$ . Future observations will extend this work to a larger sample size, increasing the reliability of polarimetry for rapid asteroid property characterization as a technique independent of previously established methods and requiring significantly fewer observations.

The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft was reactivated in December 2013 and since then has been conducting an all-sky survey at 3.4 and 4.6 microns to discover and characterize asteroids and comets that come close to the Earth. NEOWISE employs an automated pipeline for the detection of moving objects, recording their astrometry and photometry and reporting positions to the Minor Planet Center for archiving. However, there are a subset of near-Earth objects that are not found by the automated system due to rates of motion or acceleration outside the pipeline limits, an insufficient number of detections, or confusion with background sources. Because NEOWISE archives every full-frame image obtained during the survey, detections of these objects can be recovered by manually searching the expected positions for coincident sources. We have performed searches for near-Earth objects in the NEOWISE archives from 2013 to 2019, recovering detections for over 400 objects and enabling fitting of their diameters and albedos (Masiero et al. 2018, Masiero et al. 2020). This builds on earlier work that searched the data from the cryogenic phase of the original WISE mission (Mainzer et al. 2014). Objects found through this technique tend to be smaller than those detected by the automated processing. The distribution of albedos for these objects is skewed to high reflectivities, as is expected for a population that is optically-selected. Here we present the results of our searches along with the physical properties of the recovered objects. We also will discuss the reasons these objects were missed by the automated processing, and what the observed physical property distribution implies about any remaining objects still waiting to be found in the data.

Within 20 pc of the Sun there are 29 isolated sources with measured distances (Kirkpatrick et al. 2024) and an estimated temperature between that of Jupiter (170K) and∼500K – the cold brown dwarf regime. These objects are valuable laboratories for exploring the diversity of extrasolar atmospheres and comparing them to solar system gas giants. Here we report JWST observations of one such source, WISEA J153429.75-104303.3 (W1534), which we confirm is a substellar mass member of the Galactic halo with a metallicity <0.01×solar. Its spectrum reveals methane (CH4), water (H2O), and silane (SiH4) gas. Although SiH4 is expected to serve as a key reservoir for the critical cloud-forming element Si in gas giant worlds, it eluded detection in any substellar mass object (solar system or otherwise) until now because it is removed from observable atmospheres by the formation of silicate clouds at depth. These condensates are favored with increasing metallicity, explaining why SiH4 remains undetected on well studied, metal-rich solar system worlds like Jupiter and Saturn (Fegley & Lodders 1994). On the metal-poor world W1534, we detect a clear signature of SiH4 centered at∼4.55 µm with an abundance of∼20 parts per billion (ppb). Chemical models suggest it is likely quenched from regions just above the silicate cloud layers where moderate to strong vertical mixing from a pressure level of several hundred bar can transport it to the observable photosphere. The formation and detection of SiH4 – favoured by the low metallicity and short convective mixing timescales in the atmosphere of W1534 – demonstrates key coupled relationships between composition, cloud formation, and atmospheric mixing in cold brown dwarf and planetary atmospheres.

The Near-Earth Object (NEO) Surveyor mission is a NASA Observatory designed to discover and characterize asteroids and comets. The mission’s primary objective is to find the majority of objects large enough to cause severe regional impact damage (>140 m in effective spherical diameter) within its 5 yr baseline survey. Operating at the Sun–Earth L1 Lagrange point, the mission will survey to within 45° of the Sun in an effort to find objects in the most Earth-like orbits. The survey cadence is optimized to provide observational arcs long enough to distinguish near-Earth objects from more distant small bodies that cannot pose an impact hazard reliably. Over the course of its survey, NEO Surveyor will discover ∼200,000–300,000 new NEOs down to sizes as small as ∼10 m and thousands of comets, significantly improving our understanding of the probability of an Earth impact over the next century.

We present optical and infrared imaging and spectroscopy of the R Coronae Borealis-type (R Cor Bor) star IRAS 00450+7401. Optical spectra further confirm its classification as a cool R Cor Bor system, having a hydrogen-deficient carbon star spectral subclass of HdC5 or later. Mid-infrared spectroscopy reveals the typical ∼8 μ m “hump” seen in other R Cor Bor stars and no other features. A modern-epoch spectral energy distribution shows bright emission from hot dust having T _dust > 600 K. Historical infrared data reveal generally cooler dust color temperatures combined with long-term fading trends, but provide no discernible correlation between flux level and temperature. Investigating the most mid-infrared variable R Cor Bor stars found in IRAS, AKARI, and WISE data reveals similar fading trends, bursts that can show a factor of up to 10 change in flux density between epochs, and blackbody-fit dust color temperatures that span 400–1300 K. While some R Cor Bor stars such as IRAS 00450+7401 appear to undergo fade/burst cycles in the mid-infrared, significant gaps in temporal coverage prevent conclusively identifying any preferred timescale for their mid-infrared variability and circumstellar dust temperature changes.

Probing small main-belt asteroids provides insight into their formation and evolution through multiple dynamical and collisional processes. These asteroids also overlap in size with the potentially hazardous near-Earth object population and supply the majority of these objects. The Lucy mission will perform a flyby of the small main-belt asteroid, (152830) Dinkinesh, on 2023 November 1, in preparation for its mission to the Jupiter Trojan asteroids. In this Letter, we present data to support the planning of Lucy’s imminent encounter of Dinkinesh. We employed aperture photometry on stacked frames of Dinkinesh obtained by the Wide-field Infrared Survey Explorer and performed thermal modeling on a detection at 12 μ m to compute diameter and albedo values. Through this method, we determined Dinkinesh has an effective spherical diameter of 0.76 − 0.21 + 0.11 km and a visual geometric albedo of 0.27 − 0.06 + 0.25 at the 16th and 84th percentiles. This albedo is consistent with typical stony (S-type) asteroids. These measurements will enable the Lucy team to optimize planning for the flyby of Dinkinesh, including refinement of exposure times and flyby geometry. The data obtained from this mission will, in turn, allow us to better understand the calibration of our thermal models by providing ground truth data. The Lucy flyby presents a rare opportunity to study the smallest main-belt asteroid ever observed in situ.

Large potentially hazardous asteroids (PHAs) are capable of causing a global catastrophe in the event of a planetary collision. Thus, rapid assessment of such an object’s physical characteristics is crucial for determining its potential risk scale. We treated the near-Earth asteroid (99942) Apophis as a newly discovered object during its 2020–2021 close approach as part of a mock planetary defense exercise. The object was detected by the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE), and data collected by the two active bands (3.4 and 4.6 μm) were analyzed using thermal and thermophysical modeling. Our results indicate that Apophis is an elongated object with an effective spherical diameter D eff = 340 ± 70 m, a geometric visual albedo p V =0.31 ± 0.09, and a thermal inertia Γ ∼ 150–2850 J m−2 s−12 K−1 with a best-fit value of 550 J m−2 s−12 K−1. NEOWISE “discovery” observations reveal that (99942) Apophis is a PHA that would likely cause damage at a regional level and not a global one.

Sample Selection” (2018, ApJ, 866, 44) S. E. Lake , E. L. Wright , R. J. Assef , T. H. Jarrett , S. Petty , S. A. Stanford , D. Stern , and C.-W. Tsai 1 Physics and Astronomy Department, University of California, Los Angeles, CA 90095-1547, USA; lake@nao.cas.cn 2 Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejèrcito 441, Santiago, Chile 3 Astronomy Department, University of Cape Town, Private Bag X3, Rondebosch 7701, Republic of South Africa 4 NorthWest Research Associates, 4118 148th Ave. NE, Redmond, WA 98052-5164, USA 5 Department of Physics, University of California, Davis, CA 95616, USA 6 Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore CA 94551, USA 7 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA Received 2021 December 27; published 2022 March 21

The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky selected from Wide-field Infrared Survey Explorer (WISE) and NEOWISE survey data at 3.4 and 4.6 μm (W1 and W2) collected from 2010 January 7 to 2018 December 13. This data set adds two years to that used for the CatWISE Preliminary Catalog, bringing the total to six times as many exposures spanning over 16 times as large a time baseline as the AllWISE catalog. The other major change from the CatWISE Preliminary Catalog is that the detection list for the CatWISE2020 Catalog was generated using crowdsource from Schlafly et al., while the CatWISE Preliminary Catalog used the detection software used for AllWISE. These two factors result in roughly twice as many sources in the CatWISE2020 Catalog. The scatter with respect to Spitzer photometry at faint magnitudes in the COSMOS field, which is out of the Galactic Plane and at low ecliptic latitude (corresponding to lower WISE coverage depth) is similar to that for the CatWISE Preliminary Catalog. The 90% completeness depth for the CatWISE2020 Catalog is at W1 = 17.7 mag and W2 = 17.5 mag, 1.7 mag deeper than in the CatWISE Preliminary Catalog. In comparison to Gaia, CatWISE2020 motions are accurate at the 20 mas yr−1 level for W1∼15 mag sources and at the ∼100 mas yr−1 level for W1∼17 mag sources. This level of accuracy represents a 12× improvement over AllWISE. The CatWISE catalogs are available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive.

We present final Spitzer trigonometric parallaxes for 361 L, T, and Y dwarfs. We combine these with prior studies to build a list of 525 known L, T, and Y dwarfs within 20 pc of the Sun, 38 of which are presented here for the first time. Using published photometry and spectroscopy as well as our own follow-up, we present an array of color–magnitude and color–color diagrams to further characterize census members, and we provide polynomial fits to the bulk trends. Using these characterizations, we assign each object a T eff value and judge sample completeness over bins of T eff and spectral type. Except for types ≥T8 and T eff < 600 K, our census is statistically complete to the 20 pc limit. We compare our measured space densities to simulated density distributions and find that the best fit is a power law ( ) with α = 0.6 ± 0.1. We find that the evolutionary models of Saumon & Marley correctly predict the observed magnitude of the space density spike seen at 1200 K < T eff < 1350 K, believed to be caused by an increase in the cooling timescale across the L/T transition. Defining the low-mass terminus using this sample requires a more statistically robust and complete sample of dwarfs ≥Y0.5 and with T eff < 400 K. We conclude that such frigid objects must exist in substantial numbers, despite the fact that few have so far been identified, and we discuss possible reasons why they have largely eluded detection.

Coauthors/Endorsers: P. Abell (JSC), Michele T. Bannister, School of Physical and Chemical Sciences | Te Kura Matū, U. Canterbury, B. Barbee (GSFC), J. Barnes (U. Arizona), J.F. Bell III (ASU), L. Benner (JPL), B. Betts (Planetary Society), Maitrayee Bose (ASU), W. Bottke (SwRI), D. Britt (U. Central Florida), M. Brozović (JPL), M. Bruckner (U. Arizona), Michael W. Busch (SETI), S. Carey (IPAC/Caltech), J. Castillo-Rogez (JPL), J. Chesley (JPL), E. Christensen (U. Arizona), P. Chodas (JPL), D. Cotto-Figueroa (U. Puerto Rico at Humacao), M. Delbó (Observatoire de la Côte d'Azur), R. T. Daly (JHU/APL), J. Dotson (NASA-Ames), P. Eisenhardt (JPL), Y. R. Fernandez (U. Central Florida), Ronald A. Fevig (U. North Dakota), T. Grav (U. Arizona), S. Greenstreet (U. Washington), M. Gritsevich (Finnish Geospatial Research Institute), Heidi B. Hammel (AURA), A. Harris (DLR), W. Harris (U. Arizona), D. Hickson (U. Central Florida), Kynan Hughson (Georgia Institute of Technology), Željko Ivezić (U. Washington), Devanshu Jha (MVJCE, India), Lynne Jones (U. Washington), Mario Jurić (U. Washington), B. Kacar (U. Arizona), D. Lauretta (U. Arizona), Joseph Lazio (JPL), Rosaly M.C. Lopes (JPL), F. Marchis (SETI Institute), Sean E. Marshall (Arecibo/U. Central Florida), J. Masiero (JPL), D. Mathias (NASA-Ames), R. S. McMillan (U. Arizona), C. McMurtry (U. Rochester), P. Michel (U Côte d’Azur, Obs. Côte d’Azur, CNRS), S. Naidu (JPL), M. C. Nolan (U. Arizona), T. Okada (ISAS/JAXA), J. L. Pipher (U. Rochester), Carol Raymond (JPL), E. Rivera-Valentín (LPI/URSA), A. Rivkin (APL/Johns Hopkins University) C. A. Schambeau (U. Central Florida), D. Scheeres (U. Colorado), Jennifer Scully (JPL), S. Sonnett (PSI), T. Spahr (NEO Sciences), A. Stern (SwRI), T. Swindle (U. Arizona), P. Taylor (LPI/USRA), D. Takir (JSC), M. Telus (UC Santa Cruz), C. Thomas (NAU), F. C. F. Venditti (Arecibo/U. Central Florida), Anne K. Virkki (Arecibo/U. Central Florida), A. Wong (U. Arizona), E. L. Wright (UCLA)

Abstract. The Origins Space Telescope (Origins) concept is designed to investigate the creation and dispersal of elements essential to life, the formation of planetary systems, and the transport of water to habitable worlds and the atmospheres of exoplanets around nearby K- and M-dwarfs to identify potentially habitable—and even inhabited—worlds. These science priorities are aligned with NASA’s three major astrophysics science goals: How does the Universe work? How did we get here? and Are we alone? We briefly describe the science case that arose from the astronomical community and the science traceability matrix for Origins. The science traceability matrix prescribes the design of Origins and demonstrates that it will address the key science questions motivated by the science case.

Continued follow-up of WISEA J153429.75−104303.3, announced in Meisner et al., has proven it to have an unusual set of properties. New imaging data from Keck/MOSFIRE and HST/WFC3 shows that this object is one of the few faint proper motion sources known with J − ch2 >8 mag, indicating a very cold temperature consistent with the latest known Y dwarfs. Despite this, it has W1−W2 and ch1−ch2 colors ∼1.6 mag bluer than a typical Y dwarf. A new trigonometric parallax measurement from a combination of WISE, Spitzer, and HST astrometry confirms a nearby distance of 16.3−1.2+1.4 pc and a large transverse velocity of 207.4 ± 15.9 km s−1. The absolute J, W2, and ch2 magnitudes are in line with the coldest known Y dwarfs, despite the highly discrepant W1−W2 and ch1−ch2 colors. We explore possible reasons for the unique traits of this object and conclude that it is most likely an old, metal-poor brown dwarf and possibly the first Y subdwarf. Given that the object has an HST F110W magnitude of 24.7 mag, broadband spectroscopy and photometry from JWST are the best options for testing this hypothesis.

We present follow-up Spitzer observations at 3.6 mu m (ch1) and 4.5 mu m (ch2) of CWISEP J144606.62-231717.8, one of the coldest known brown dwarfs in the solar neighborhood. This object was found by mining the Wide-field Infrared Survey Explorer (WISE) and NEOWISE data via the CatWISE Preliminary Catalog by Meisner et al., where an initial Spitzer color of ch1-ch2 = 3.71 0.44 mag was reported, implying it could be one of the reddest, and hence coldest, known brown dwarfs. Additional Spitzer data presented here allows us to revise its color to ch1-ch2 = 2.986 0.048 mag, which makes CWISEP J144606.62-231717.8 the fifth reddest brown dwarf ever observed. A preliminary trigonometric parallax measurement, based on a combination of WISE and Spitzer astrometry, places this object at a distance of Spitzer color and preliminary parallax, CWISEP J144606.62-231717.8 has a T-eff in the 310-360 K range. Assuming an age of 0.5-13 Gyr, this corresponds to a mass between 2 and 20 M-Jup.

We present Very Large Telescope/XSHOOTER rest-frame UV–optical spectra of 10 hot dust-obscured galaxies (Hot DOGs) at z ∼ 2 to investigate active galactic nucleus (AGN) diagnostics and assess the presence and effect of ionized gas outflows. Most Hot DOGs in this sample are narrow-line-dominated AGNs (type 1.8 or higher) and have higher Balmer decrements than typical type 2 quasars. Almost all (8/9) sources show evidence for ionized gas outflows in the form of broad and blueshifted [O iii ] profiles, and some sources have such profiles in H α (5/7) or [O ii ] (3/6). Combined with the literature, these results support additional sources of obscuration beyond the simple torus invoked by AGN unification models. Outflow rates derived from the broad [O iii ] line (≳10 3 M ⊙ yr −1 ) are greater than the black hole accretion and star formation rates, with feedback efficiencies (∼0.1%–1%) consistent with negative feedback to the host galaxy’s star formation in merger-driven quasar activity scenarios. We find that the broad emission lines in luminous, obscured quasars are often better explained by outflows within the narrow-line region and caution that black hole mass estimates for such sources in the literature may have substantial uncertainty. Regardless, we find lower bounds on the Eddington ratio for Hot DOGs near unity.

CatWISE is a program to catalog sources selected from combined WISE and NEOWISE all-sky survey data at 3.4 and 4.6 mu m (W1 and W2). The CatWISE Preliminary Catalog consists of 900,849,014 sources measured in data collected from 2010 to 2016. This data set represents four times as many exposures and spans over 10 times as large a time baseline as that used for the AllWISE Catalog. CatWISE adapts AllWISE software to measure the sources in coadded images created from six-month subsets of these data, each representing one coverage of the inertial sky, or epoch. The catalog includes the measured motion of sources in eight epochs over the 6.5 yr span of the data. From comparison to Spitzer, signal-to-noise ratio = 5 limits in magnitudes in the Vega system are W1 = 17.67 and W2 = 16.47, compared to W1 = 16.96 and W2 = 16.02 for AllWISE. From comparison to Gaia, CatWISE positions have typical accuracies of 50 mas for stars at W1 = 10 mag and 275 mas for stars at W1 = 15.5 mag. Proper motions have typical accuracies of 10 mas yr(-1) and 30 mas yr(-1) for stars with these brightnesses, an order of magnitude better than from AllWISE. The catalog is available in the WISE/NEOWISE Enhanced and Contributed Products area of the NASA/IPAC Infrared Science Archive.