E. L. Wright’s research while affiliated with University of California, Los Angeles and other places

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Publications (268)


Cross Validation of Albedo Determination for 1627 Ivar from Three Different Techniques
  • Article
  • Full-text available

January 2025

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26 Reads

The Planetary Science Journal

Elena Selmi

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J. R. Masiero

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[...]

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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.

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Cross validation of albedo determination for 1627 Ivar from three different techniques

January 2025

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6 Reads

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 HVH_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 0.240.02+0.040.24^{+0.04}_{-0.02} . 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 Surveyor Mission

December 2023

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257 Reads

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47 Citations

The Planetary Science Journal

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.



WISE/DEIMOS Redshift Catalog DR2
Erratum: “The 2.4 μm Galaxy Luminosity Function as Measured Using WISE. II. Sample Selection” (2018, ApJ, 866, 44)

March 2022

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15 Reads

The Astrophysical Journal



Figure 2. Fractional diameter uncertainty (σ D /D) for all NEO measurements in NEOWISE Years 6 and 7 vs. phase angle. The uncertainty shown here only includes the statistical component determined through our Monte Carlo analysis. Objects at smaller phase angles show larger fractional uncertainties because the peak of thermal emission is further from the W2 bandpass, providing a weaker constraint on the size given the large range of possible beaming values.
Figure 7. Comparison of the argument of perihelion to different orbital parameters for all MBAs discovered by NEOWISE during the Reactivation mission. Comparisons with perihelion distance (panel (b)) and decl. (panel (g)) show the most significant structure.
Thermal Model Fits for NEOs Detected in the Seventh Year of the NEOWISE Survey
Thermal Model Fits for MBAs Detected in the Seventh Year of the NEOWISE Survey
Asteroid Diameters and Albedos from NEOWISE Reactivation Mission Years Six and Seven

August 2021

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99 Reads

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29 Citations

The Planetary Science Journal

We present diameters and albedos computed for the near-Earth and main belt asteroids (MBAs) observed by the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft during the sixth and seventh years of its Reactivation mission. These diameters and albedos are calculated from fitting thermal models to NEOWISE observations of 199 near-Earth objects (NEOs) and 5851 MBAs detected during the sixth year of the survey and 175 NEOs and 5861 MBAs from the seventh year. Comparisons of the NEO diameters derived from Reactivation data with those derived from the WISE cryogenic mission data show a ~30% relative uncertainty. This larger uncertainty compared to data from the cryogenic mission is due to the need to assume a beaming parameter for the fits to the shorter-wavelength data that the Reactivation mission is limited to. We also present an analysis of the orbital parameters of the MBAs that have been discovered by NEOWISE during Reactivation, finding that these objects tend to be on orbits that result in their perihelia being far from the ecliptic, and thus missed by other surveys. To date, the NEOWISE Reactivation survey has provided thermal fits of 1415 unique NEOs. Including the mission phases before spacecraft hibernation increases the count of unique NEOs characterized to 1845 from WISE's launch to the present.



Asteroid Diameters and Albedos from NEOWISE Reactivation Mission Years Six and Seven

July 2021

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7 Reads

We present diameters and albedos computed for the near-Earth and Main Belt asteroids observed by the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft during the sixth and seventh years of its Reactivation mission. These diameters and albedos are calculated from fitting thermal models to NEOWISE observations of 199 NEOs and 5851 MBAs detected during the sixth year of the survey, and 175 NEOs and 5861 MBAs from the seventh year. Comparisons of the near-Earth object diameters derived from Reactivation data with those derived from the WISE cryogenic mission data show a 30%\sim30\% relative uncertainty. This larger uncertainty compared to data from the cryogenic mission is due to the need to assume a beaming parameter for the fits to the shorter wavelength data that the Reactivation mission is limited to. We also present an analysis of the orbital parameters of the Main Belt asteroids that have been discovered by NEOWISE during Reactivation, finding that these objects tend to be on orbits that result in their perihelia being far from the ecliptic, and thus missed by other surveys. To date, the NEOWISE Reactivation survey has provided thermal fits of 1415 unique NEOs. Including the mission phases before spacecraft hibernation increases the count of unique NEOs characterized to 1845 from WISE's launch to the present.



Citations (40)


... Although the WISE telescope was retired in July 2024, the Near-Earth Object Surveyor (Mainzer et al. 2023) will work on in 2027. Furthermore, there will be some wide-field NIR survey projects in the future, such as the wide-field infrared transient explorer (WINTER, Lourie et al. 2020), PRime-focus Infrared Microlensing Experiment (PRIME, Kondo et al. 2023), and the Nancy Grace Roman Space Telescope (Akeson et al. 2019). ...

Reference:

Distinguishing Tidal Disruption Events and Changing-look Active Galactic Nuclei via Variation of Mid-infrared Color
The Near-Earth Object Surveyor Mission

The Planetary Science Journal

... The spacecraft was reactivated in 2013 December as NEOWISE (Mainzer et al. 2011) and conducted a sky survey in the 3.4 and 4.6 µm bands to focus on NEO discovery and characterization. As of 2021, a total of 1845 unique NEOs have been characterized from the beginning of the cryogenic mission through year 7 of NEOWISE (Masiero et al. 2021). The WISE satellite was decommissioned in August 2024. ...

Asteroid Diameters and Albedos from NEOWISE Reactivation Mission Years Six and Seven

The Planetary Science Journal

... In 2005, NASA was given a mission to find and track 90% of all Potentially Hazardous Asteroids (PHA) by the end of 2020. The significantly increased efforts resulted in an exponential increase in the number of objects discovered in the following years. 1 Ground-based search campaigns like the Vera C. Rubin Observatory or the Flyeye telescope (ESA) and space missions like the NEO surveyor space mission (NASA) are expected to increase the number of discovered objects in the next years significantly (Cibin et al., 2019;Mainzer et al., 2021). Data are collected internationally in a centralized manner by the Minor Planet Center (MPC) and made available for further evaluations. ...

The Future of Planetary Defense in the Era of Advanced Surveys

... Approximately 70% of potential detections had no associated source returned by IRSA; the most likely cause for this is that real NEOs had higher albedos than our assumed value, which would translate to smaller sizes and fainter IR fluxes when using the H V magnitude and an assumed size. This fraction is consistent with the known bias toward higher-albedo NEOs for objects discovered by ground-based surveys (Masiero et al. 2020). ...

Physical Properties of 299 NEOs Manually Recovered in Over Five Years of NEOWISE Survey Data

The Planetary Science Journal

... R. Masiero et al. 2012), with the newest determination of 60.94 ± 13.950 (J. R. Masiero et al. 2020), complicating the occultation campaign planning that aimed at dense and uniform coverage of the predicted asteroid shadow. ...

Asteroid Diameters and Albedos from NEOWISE Reactivation Mission Years 4 and 5

The Planetary Science Journal

... The rationale for intentionally limiting our model to this simple color space, artificially, is precisely because keeping distributions of different source types overlapping makes the effect that deweighting compensates for most apparent. Some examples of features that could be added that would greatly increase the accuracy of a classification model include: the W1 magnitude ( Figure 8, Panel a of Lake et al. (2019) shows that at Galactic latitude b > 30 • a source with W1 < 18.2 mag is more likely to be a star, and fainter sources are more likely extragalactic), pure morphological information (e.g. the χ 2 information from 2MASS or All-WISE for how well the psf fit the source can indicate a source is extended, or contaminated, (Cutri et al., , 2013), parallaxes (by cross matching to, for example, Gaia Collaboration et al. (2018)), or just adding more colors. Section 3.4 describes an expansion of the star/galaxy/AGN problem to include blazars, specifically flat spectrum radio quasars (FSRQs) and BL Lacertae objects (BL Lacs). ...

The Contribution of Galaxies to the 3.4 μ m Cosmic Infrared Background as Measured Using WISE

The Astrophysical Journal

... As Tancredi et al. (2006), we then assumed that MPC report R-magnitudes. The average post-perihelion apparent magnitude of K1 in August, 07.505 2016 UT was m app = 21.50 ± 0.07 (1σ ) (Williams 2016). In this moment, the comet was at r=7.847 A.U. and with a phase angle α = 3.1 degrees, and activity level (Afρ(0) = 58 ± 4 cm) which is lower than other LPC at similar heliocentric distances (e.g Sárneczky et al. 2016). ...

MPEC 2019-V116 : Observations and orbits of comets
  • Citing Article
  • November 2019

... [1][2][3]11,12]). Understanding thermal conditions on the asteroid surface are highly relevant since (i) the thermal radiation is an observable value and is thus a diagnostic value in size estimation [13,14]; (ii) if the thermal inertia is obtained, the size of grains covering the asteroid can be estimated [15][16][17][18]; and (iii) the temperature distribution can affect the motion and spin of the asteroid [19,20]. ...

Thermophysical Modeling of NEOWISE Observations of DESTINY + Targets Phaethon and 2005 UD
  • Citing Article
  • August 2019

The Astronomical Journal

... An initial application of the CatWISE catalog was the first secure W2 detection for the Y dwarf WD0806-661 B (Meisner et al. 2018a), leading to a [4.5] -W2 color consistent with the population of known Y dwarfs. CatWISE represents a major hunting ground for cold brown dwarfs. ...

A Secure W2 Detection of WD 0806-661B from CatWISE
  • Citing Article
  • August 2018

Research Notes of the AAS