Explanipedia

First Resolution of a Main Sequence G-Star Astrosphere Using Chandra Open

C. M. Lisse, S. J. Wolk, Bradford Snios, J.R. McNutt, Jonathan D. Slavin , et al. · 2025

We report resolution of a halo of X-ray line emission surrounding the Zero Age Main Sequence (ZAMS) G8.5V star HD 61005 by Chandra ACIS-S. Located only 36.4 pc distant, HD 61005 is young (approx. 100 Myr), x-ray bright (300 times Solar), o…

Measuring the Shapes of Kuiper Belt Objects with New Horizons Photometry Open

Simon B. Porter, K. N. Singer, A. Verbiscer, W. M. Grundy, Susan Benecchi , et al. · 2025

NASA’s New Horizons spacecraft provided the first look at the full shape of a primordial Kuiper Belt Object (KBO) when it encountered the Cold Classical KBO (486958) Arrokoth on January 1, 2019. Arrokoth proved to be a contact binary, comp…

Update on NASA’s New Horizons Mission: Kuiper Belt Science Results and Future Plans Open

K. N. Singer, Alan J. Stern, A. Verbiscer, Simon B. Porter, William Grundy , et al. · 2025

NASA’s New Horizons spacecraft continues to explore the Kuiper belt after its historic close flybys of the Pluto system in 2015 at ~33 astronomical units (AU) [1] and the cold classical Kuiper belt object (KBO) Arrokoth in 2019 at ~43 AU […

A framework to predict Low- to High-Energy Neutral Atoms (LHENAs) Observations in Support of Planetary Exploration Open

Daniel Santos‐Costa, Angèle Pontoni, C. Grava, J. Mukherjee, Nicolás André , et al. · 2025

Imaging of fluxes of Energetic Neutral Atoms (ENAs) had provided a means to improve our understanding of global magnetospheric and heliospheric processes since the mid-1990s. The remarkable science results from ENA-imaging-based studies of…

Particle Environment Package (PEP) for the Juice Mission: Current Status Open

S. Barabash, P. C. Brandt, P. Wurz, George Clark, M. Fräenz , et al. · 2025

The Particle Environment Package (PEP) onboard ESA’s Jupiter Icy Moons Explorer (JUICE) provides particle measurements to address three overarching science questions:How does Jupiter’s co-rotating magnetosphere interact with Ganymede, Call…

Predictions for New Horizons’ SWAP Measurements Downstream of the Heliospheric Termination Shock Open

E. J. Zirnstein, D. J. McComas, Bishwas L. Shrestha, H. A. Elliott, P. C. Brandt , et al. · 2025

Currently ∼62 au from the Sun, the New Horizons spacecraft is en route to the outer heliosphere boundaries. The first boundary it will encounter is the heliospheric termination shock (HTS), where the solar wind ion (SWI) and interstellar p…

A Demonstration of Interstellar Navigation Using New Horizons Open

Tod R. Lauer, D. H. Munro, J. R. Spencer, M. W. Buie, Edward Gomez , et al. · 2025

As NASA’s New Horizons spacecraft exits the solar system bound for interstellar space, it has traveled so far that the nearest stars have shifted markedly from their positions seen from Earth. We demonstrated this by imaging the Proxima Ce…

A Demonstration of Interstellar Navigation Using New Horizons Open

Tod R. Lauer, D. H. Munro, J. R. Spencer, M. W. Buie, Edward Gomez , et al. · 2025

As NASA's New Horizons spacecraft exits the Solar System bound for interstellar space, it has traveled so far that the nearest stars have shifted markedly from their positions seen from Earth. We demonstrated this by imaging the Proxima Ce…

Formation of H<sup>+</sup> PUI Tails Downstream of Distant Interplanetary Shocks Open

E. J. Zirnstein, D. J. McComas, Bishwas L. Shrestha, H. A. Elliott, P. C. Brandt , et al. · 2025

New Horizons’ Solar Wind Around Pluto (SWAP) instrument has observed interplanetary shocks from ∼20 to 60 au from the Sun. Different studies have analyzed the effects of these shocks on the solar wind ion (SWI) and interstellar pickup ion …

The Ly<i>α</i> Sky as Observed by New Horizons at 57 au Open

G. R. Gladstone, J. Michael Shull, W. R. Pryor, Jonathan D. Slavin, Joshua A. Kammer , et al. · 2025

During 2023 September the Alice ultraviolet spectrograph on the New Horizons (NH) spacecraft was used to map diffuse Lyα emission over most of the sky, at a range of ∼56.9 au from the Sun. At that distance, models predict that the interpla…

High-resolution Observations of Pickup-ion-mediated Shocks to 60 au Open

Bishwas L. Shrestha, D. J. McComas, E. J. Zirnstein, G. Livadiotis, H. A. Elliott , et al. · 2025

This study provides a detailed analysis of 14 distant interplanetary shocks observed by the Solar Wind Around Pluto instrument on board New Horizons. These shocks were observed with a pickup ion data cadence of approximately 30 minutes, co…

High-Resolution Observations of Pickup Ion Mediated Shocks to 60 au Open

Bishwas L. Shrestha, D. J. McComas, E. J. Zirnstein, G. Livadiotis, H. A. Elliott , et al. · 2025

This study provides a detailed analysis of fourteen distant interplanetary shocks observed by the Solar Wind Around Pluto (SWAP) instrument onboard New Horizons. These shocks were observed with a pickup ion data cadence of approximately 30…

An Extremely Deep Rubin Survey to Explore the Extended Kuiper Belt and Identify Objects Observable by New Horizons Open

J. J. Kavelaars, M. W. Buie, Wesley C. Fraser, Lowell Peltier, Susan Benecchi , et al. · 2025

A proposed Vera C. Rubin Observatory Deep Drilling micro-survey of the Kuiper Belt will investigate key properties of the distant solar system. Utilizing 30 hours of Rubin time across six 5-hour visits over one year starting in summer 2026…

Magnetosphere and Plasma Science with the Jupiter Icy Moons Explorer Open

A. Masters, R. Modolo, E. Roussos, N. Krupp, Olivier Witasse , et al. · 2025

Interstellar Pickup Ion Observations to 60 au Open

D. J. McComas, Bishwas L. Shrestha, G. Livadiotis, J. R. Szalay, E. J. Zirnstein , et al. · 2025

Prior to the Solar Wind Around Pluto (SWAP) observations from New Horizons, the only significant interstellar pickup ion (PUI) observations were taken inside 5.4 au from the Ulysses and 1 au missions. Here, we analyze SWAP data to provide …

Production, Transport, and Destruction of Dust in the Kuiper Belt: The Effects of Refractory and Volatile Grain Compositions Open

Thomas Corbett, Alex Doner, M. Horányi, P. C. Brandt, W. M. Grundy , et al. · 2025

The Venetia Burney Student Dust Counter (SDC) on board the New Horizons spacecraft measures the spatial and size distributions of dust along its trajectory. Models based on early SDC measurements predicted a peak dust number density at a h…

Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View Open

Jayant Murthy, J. Michael Shull, Marc Postman, J. W. Parker, Seth Redfield , et al. · 2025

We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes (∣ b ∣ > 40 ∘ ), made using the Alice UV spectrograph on board the New Horizons spacecraft. These observations were taken at about 57 au fro…

PUI Heating in the Supersonic Solar Wind Open

Parisa Mostafavi, L. Adhikari, Bishwas L. Shrestha, G. P. Zank, M. Opher , et al. · 2025

The outer heliosphere is profoundly influenced by nonthermal energetic pickup ions (PUIs), which dominate the internal pressure of the solar wind beyond ~10 au, surpassing both solar wind and magnetic pressures. PUIs are formed mostly thro…

Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View Open

Jayant Murthy, J. Michael Shull, Marc Postman, J. W. Parker, Seth Redfield , et al. · 2025

We present new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes ($|b| > 40^{\circ}$), made using the Alice UV spectrograph on board the New Horizons spacecraft. These observations were taken at about 57 A…

Termination Shock Particle Streaming Upstream at New Horizons Open

Erick Powell, M. Opher, Ethan Bair, M. E. Hill, Romina Nikoukar , et al. · 2024

A couple years before Voyager 1 and Voyager 2 (V2) crossed the termination shock (TS), instruments on board both spacecraft observed high intensities of accelerated termination shock particles (TSPs) beaming in opposite directions. This ph…

Observations of Uranus at High Phase Angle as Seen by New Horizons Open

Samantha Hasler, L. C. Mayorga, W. M. Grundy, Amy Simon, Susan Benecchi , et al. · 2024

We present flux measurements of Uranus observed at phase angles of 43.°9, 44.°0, and 52.°4 by the Multispectral Visible Imaging Camera on the New Horizons spacecraft during 2023, 2010, and 2019, respectively. New Horizons imaged Uranus at …

New Synoptic Observations of the Cosmic Optical Background with New Horizons Open

Marc Postman, Tod R. Lauer, J. W. Parker, J. R. Spencer, H. A. Weaver , et al. · 2024

We obtained New Horizons LORRI images to measure the cosmic optical background (COB) intensity integrated over 0.4 μ m ≲ λ ≲ 0.9 μ m. The survey comprises 16 high-Galactic-latitude fields selected to minimize scattered diffuse Galactic lig…

New Synoptic Observations of the Cosmic Optical Background with New Horizons Open

Marc Postman, Tod R. Lauer, J. W. Parker, J. R. Spencer, H. A. Weaver , et al. · 2024

We obtained New Horizons LORRI images to measure the cosmic optical background (COB) intensity integrated over $0.4\lesssimλ\lesssim0.9{~\rmμm}.$ The survey comprises 16 high Galactic-latitude fields selected to minimize scattered diffuse …

Unique Heliospheric Measurement Opportunities with the ESA JUICE mission: Science Case for Particle Environment Package (PEP) Open

S. Barabash, P. C. Brandt, P. Wurz, G. Clark, N. Krupp , et al. · 2024

The Jupiter bound JUICE mission (JUpiter ICy moons Explorer) was successfully launched on April 14, 2023 and is currently executing its 8-year interplanetary cruise phase. JUICE carries three comprehensive instrument suites to fully charac…

Heliospheric and cosmic dust science with Interstellar Probe and with missions inside the solar system Open

Veerle Sterken, S. Hunziker, K. Dialynas, Lennart R. Baalmann, Arthur Péronne , et al. · 2024

Cosmic dust particles with sufficiently high charge-to-mass ratios interact with the heliosphere on both global and local scales due to the coupling of the charged dust with the heliospheric plasma. They are the fingerprints of heliospheri…

Energetic charged particle observations of Europa’s near-space environment during the Juno PJ45 flyby and anticipations for the JUICE mission  Open

G. Clark, B. H. Mauk, C. Paranicas, P. C. Brandt, P. Kollmann , et al. · 2024

Jupiter’s moon Europa is of high scientific interest because it is an ocean world with a tenuous atmosphere and may also harbor sporadic water plumes. Europa is also embedded deep within Jupiter’s magnetosphere and resides in a…

Periodic narrowband radio wave emissions and inward plasma transport at Saturnian Open

Xuanye Ma, S. Wing, P. C. Brandt, J. Johnson, D. G. Mitchell , et al. · 2024

The abrupt brightening of an Energetic Neutral Atom (ENA) blob or cloud has been interpreted as plasma injection in the Saturnian magnetosphere (termed ENA injection herein). Morphologically, there appears to be two types of abrupt ENA clo…

Measurement of the Composition of the Local Interstellar Cloud with the Interstellar Probe Mission Open

P. Wurz, Rico Fausch, Jonathan Gasser, André Galli, Audrey Vorburger , et al. · 2024

The proposed Interstellar Probe (IP) spacecraft of NASA will travel through the heliosphere and advance into the local interstellar medium (LISM) within roughly 16 years, i.e., at twice the speed as the Voyager spacecraft. IP will enable t…

Energetic Neutral Atom (ENA) Imaging and In-Situ Energetic Particle Exploration of the Jovian Magnetosphere and Moon Environment from JUICE/PEP Open

P. C. Brandt, G. Clark, P. Kollmann, D. G. Mitchell, Malamati Gkioulidou , et al. · 2024

The Jovian Energetic Neutrals and Ions (JENI) Camera and the Jovian Energetic Electrons (JoEE) belong to the six-sensor suite Particle Environment Package (PEP) on board the JUICE mission. JENI is a combined ion and ENA camera with 90˚…

New Horizons Venetia Burney Student Dust Counter Observes Higher than Expected Fluxes Approaching 60 au Open

Alex Doner, M. Horányi, F. Bagenal, P. C. Brandt, W. M. Grundy , et al. · 2024

The NASA New Horizons Venetia Burney Student Dust Counter (SDC) measures dust particle impacts along the spacecraft’s flight path for grains with mass ≥10 −12 g, mapping out their spatial density distribution. We present the latest SDC dus…

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