Tag

Occultation

All articles tagged with #occultation

space20 days ago•7 min saved

Chariklo’s shifting rings hint at active dynamics in the smallest ringed world

New JWST occultation data show Chariklo’s two rings have evolved: the inner ring C1R thickened while the outer ring C2R faded, suggesting real temporal evolution rather than just a viewing geometry effect. Explanations include wavelength-dependent scattering in infrared or actual material transfer, possibly aided by an unseen shepherd satellite. A follow-up visible-light occultation is needed to confirm the cause and distinguish true change from observation effects.

via Ars Technica|

#chariklo #jwst #minor-bodies

space25 days ago•12 min saved

Chariklo’s Tiny Ring System May Be in Flux, Webb Observations Hint

Chariklo, a ~250‑km icy body, hosts two very narrow rings whose opacities appear to change on yearly timescales: the inner C1R became about 50% more opaque and the outer C2R faded by roughly 60% since 2017, while the rings’ radii stayed essentially the same. Webb’s 2022 near‑infrared occultation, alongside earlier visible observations, suggests this could reflect dust grain size or composition effects rather than outright material loss, though both are possible. Explanations range from new material or collision-produced grain clouds in the inner ring to continued confinement or replenishment mechanisms for the outer ring, such as shepherd moons or resonances. The study indicates Chariklo’s rings are dynamic rather than static ornaments, and further occultations are needed to confirm the causes of the changes.

via Space Daily|

#chariklo #occultation #opacity

science26 days ago•134 min saved

JWST uncovers dynamic, evolving rings around Chariklo

Using the James Webb Space Telescope, astronomers found that Chariklo’s two rings are changing: the inner ring is becoming more opaque while the outer ring is less opaque, revealed through stellar occultations observed since 2022. The results, published in Science Advances, suggest more complex ring physics than previously thought and prompt a reevaluation of how rings form and evolve on small solar-system bodies, aided by Gaia’s precise orbital data and JWST’s mission at the L2 point.

via Space|

#chariklo #james-webb-space-telescope #occultation

space1 month ago•11 min saved

Tiny 500-km world beyond Neptune may host a fleeting atmosphere

A 2024 stellar occultation suggests the 500-km trans-Neptunian object 2002 XV93 has a global atmosphere of about 100–200 nanobars, thin but detectable for such a small body; without replenishment it would escape in under 1,000 years. The gas species aren’t identified yet, and possible sources include a recent collision or ongoing cryovolcanism. Webb observations found no obvious surface ice reservoir to explain it, so independent verification through future occultations or infrared spectroscopy is needed to determine the origin and fate of this ephemeral atmosphere.

via Space Daily|

#atmosphere #cryovolcanism #impact

space1 month ago•14 min saved

One-pixel Earth hides behind Phobos: Perseverance captures historic occultation from Mars

NASA’s Perseverance rover on Mars recorded a nine-image sequence in which Earth, a one-pixel dot 314 million kilometres away, passes behind Phobos, marking the first observation of Earth disappearing behind another world from the surface of a different planet; the event is presented as an annotated composite rather than a continuous video, highlighting careful geometry and timing.

via Space Daily|

#earth #mars #occultation

space-and-astronomy1 month ago•55 min saved

Pluto’s atmosphere begins to freeze out as it drifts farther from the Sun

Astronomers report Pluto’s nitrogen-rich atmosphere is starting to freeze out as it moves away from the Sun, with atmospheric pressure dropping about 16% between mid-2021 and 2023. Pluto’s surface runs at roughly -382°F while the upper atmosphere sits around -333°F, conditions that favor frost formation as the air cools. Observations of ten stellar occultations from 2017–2023 show haze in the lower atmosphere settling toward lower latitudes as pressure falls. The findings, led by Amanda Sickafoose, suggest the atmosphere will not be fully frozen by aphelion (2114) but should rebuild somewhat as Pluto travels back toward the Sun. The study was published July 31 in the Planetary Science Journal.

via Yahoo|

#atmosphere #frost #nitrogen

space2 months ago•159 min saved

Pluto's Atmosphere Freezes as It Moves Away from the Sun

Pluto’s nitrogen‑rich atmosphere is starting to condense into frost as it drifts farther from the Sun on its 248‑year orbit. Surface temperatures are about -382°F (-230°C) and the upper atmosphere around -333°F (-203°C). Observations of ten stellar occultations from 2017–2023 show atmospheric pressure has declined ~16% since 2021 (likely haze settling to lower latitudes). NASA’s New Horizons had measured a baseline atmospheric pressure of about 10 microbars in 2015. Pluto’s aphelion will occur in 2114 at ~49 AU, and the atmosphere isn’t expected to be fully frozen by then; frost could sublimate and the atmosphere thicken again as Pluto heads back toward the Sun.

via Space|

#atmosphere #frost #new-horizons

science3 months ago•2 min saved

Small Kuiper Belt Object Displays a Fragile Atmosphere, Defying Expectations

Astronomers using a 2024 stellar occultation detected signs of a thin, possibly temporary atmosphere around the tiny Kuiper Belt object 2002 XV93 (about 500 km across), challenging assumptions that such small bodies can hold an atmosphere. Any atmosphere would likely last under 1,000 years without replenishment, and no frozen surface gases were found by JWST to fuel it. Two scenarios are proposed: recent internal gas release or a comet impact. If confirmed, this would be the first atmosphere detected on a trans-Neptunian object other than Pluto, prompting further observations to understand the mechanism.

via BBC Sky at Night Magazine|

#2002-xv93 #atmosphere #kuiper-belt

space3 months ago•95 min saved

Sunlit occultation: Moon briefly veils Venus in daylight on June 17

On June 17, a rare daytime occultation will have a thin crescent Moon pass in front of Venus across parts of North America in the mid‑afternoon; observers can use binoculars or a telescope but must avoid looking near the Sun, while the Moon serves as a guide to spot Venus (magnitude -4.0) in daylight; the event runs roughly 3:30–5:00 PM EDT, followed by evening views near the Beehive Cluster after sunset.

via Space|

#daytime-sky #moon #occultation

science3 months ago•4 min saved

Daylight Moon Occults Venus in Rare 2026 Sky Show

On June 17, 2026, the Moon will occult Venus in broad daylight for about 29 seconds, centered around 16:40 EDT, visible from northeastern South America, the Caribbean, the CONUS, northern Mexico and southern Canada before sunset; Venus will be about 38 degrees from the Sun and around magnitude -4, while the Moon is an 11 percent crescent. This is the first of three Venus occultations in 2026 (Sept 14 and Nov 7 are the others), with Mercury near greatest elongation the day before. Plan with IOTA timings or Stellarium to target local times and try daytime video capture, noting autofocus can be tricky.

via ScienceAlert|

#mercury #moon #occultation

science5 months ago•3 min saved

Tiny Kuiper World Reveals Thin Atmosphere, Second of Its Kind

Astronomers observed the small Kuiper Belt object 2002 XV93 (about 311 miles across) during a stellar occultation and found a very thin atmosphere, making it only the second TNO known to have one after Pluto. The atmosphere, five to ten million times thinner than Earth's, could result from cryovolcanic activity or a recent icy impact; its persistence or dissipation could help distinguish between these sources. Future James Webb Space Telescope observations may detect additional gases like methane or carbon monoxide.

via Futurism|

#atmosphere #cryovolcanism #kuiper-belt

space5 months ago•74 min saved

Tiny Kuiper Belt World Grows a Mysterious, Vanishingly Thin Atmosphere

A diminutive trans-Neptunian object known as (612533) 2002 XV93 (a ~500 km Pluto-like body in Neptune’s 2:3 resonance) has unexpectedly developed a thin atmosphere (exosphere). Its presence was inferred from a January 2024 stellar occultation observed by a Japan-led team; the exosphere is extremely tenuous, with surface pressures of 100–200 nanobars—5 to 10 million times thinner than Earth’s. The atmosphere could originate from a recent impact or from cryovolcanic outgassing, but either way it challenges the idea that only large bodies can sustain atmospheres. If it’s impact-driven, the gas would escape within ~1,000 years; if outgassing, the source is ongoing beneath the surface. JWST observations and density monitoring in coming years should help pinpoint the cause. The discovery was published May 4 in Nature Astronomy.

via Space|

#atmosphere #cryovolcanism #kuiper-belt

space5 months ago•5 min saved

Tiny Kuiper Object Wears a Breath: Atmosphere Detected on a 500-km Plutino

Astronomers detected a surprisingly thin atmosphere around 2002 XV93, a ~500-km plutino in the Kuiper belt, via a 2024 stellar occultation observed from Japan. The inferred atmosphere is about 100–200 nanobars—extremely tenuous and likely transient—suggesting replenishment from a recent impact or ongoing cryovolcanism. This challenges the notion that atmospheres only form on large bodies and shows that small distant objects can host detectable atmospheres, with the research published in Nature Astronomy.

via ScienceAlert|

#2002-xv93 #atmosphere #occultation

science5 months ago•3 min saved

Tiny Distant World Displays Pluto-like Thin Atmosphere

Astronomers using stellar occultations found that (612533) 2002 XV93, a ~500-km trans-Neptunian object, has a thin, Pluto-like atmosphere, making it the first TNO with an atmosphere; the feature could be temporary or long-lasting, and further multi-site observations are planned to uncover its origin and evolution.

via Gizmodo|

#astronomy #atmosphere #occultation

science5 months ago•13 min saved

Whisper-thin atmosphere detected on a tiny Kuiper Belt world

Astronomers observed a January 2024 stellar occultation by trans-Neptunian object (612533) 2002 XV93, seeing its background star fade and recover, which provides evidence for a very thin atmosphere around this Pluto-like distant world in the Kuiper Belt.

via AP News|

#astronomy #atmosphere #occultation