Astro Wonders

2022-06-24 06:22:42 The Orion Nebula.

This is one of the brightest nebulae, so it can be observed without the use of technology. Its apparent size is 4 times larger than the moon.

@thewonderofspace Open / Comment

2022-06-23 18:25:22 Scientists Identify a Possible Source for Red Cap on Pluto’s Largest Moon Charon

Research combined spacecraft data with new lab experiments and models of Pluto’s largest moon.

Southwest Research Institute (SwRI) scientists combined data from NASA’s New Horizons mission with cutting-edge laboratory experiments and exospheric modeling to reveal the likely composition of the red cap on Pluto’s moon Charon and how it may have formed. This first-ever description of Charon’s dynamic methane atmosphere using new experimental data provides a fascinating glimpse into the origins of this moon’s red spot as described in two recent papers.

Soon after the 2015 encounter, New Horizons scientists proposed that a reddish “tholin-like” material at Charon’s pole could be synthesized by ultraviolet light breaking down methane molecules. These are captured after escaping from Pluto and then frozen onto the moon’s polar regions during their long winter nights. Tholins are sticky organic residues formed by chemical reactions powered by light, in this case the Lyman-alpha ultraviolet glow scattered by interplanetary hydrogen atoms.

The team realistically replicated Charon surface conditions at SwRI’s new Center for Laboratory Astrophysics and Space Science Experiments (CLASSE) to measure the composition and color of hydrocarbons produced on Charon’s winter hemisphere as methane freezes beneath the Lyman-alpha glow. The team fed the measurements into a new atmospheric model of Charon to show methane breaking down into residue on Charon’s north polar spot.

The team input the results from SwRI’s ultra-realistic experiments into the atmospheric model to estimate the distribution of complex hydrocarbons emerging from methane decomposition under the influence of ultraviolet light. The model has polar zones primarily generating ethane, a colorless material that does not contribute to a reddish color.

The team think ionizing radiation from the solar wind decomposes the Lyman-alpha-cooked polar frost to synthesize increasingly complex, redder materials responsible for the unique albedo on this enigmatic moon. Ethane is less volatile than methane and stays frozen to Charon’s surface long after spring sunrise. Exposure to the solar wind may convert ethane into persistent reddish surface deposits contributing to Charon’s red cap.

@thewonderofspace Open / Comment

2022-06-23 18:17:17 Mercury-bound spacecraft whizzes past the smallest planet for the 2nd time

The Mercury-bound probe BepiColombo has taken its second look at its target planet today during a superclose flyby designed to slow the spacecraft down and adjust its trajectory.

BepiColombo is a joint mission by the European Space Agency and the Japan Aerospace Exploration Agency. The mission, consisting of two orbiters that travel to Mercury stacked on top of each other, launched into orbit around the sun in 2018. Since then, ground controllers have been adjusting the spacecraft's trajectory through a series of nine flyby maneuvers to gradually slow BepiColombo down so that it can enter orbit around the solar system's innermost planet in 2025.

The June 23 flyby was BepiColombo's second at Mercury, following the probe's first encounter with the planet in October 2021. The probe made its closest approach to Mercury's surface at 0944 GMT, when it passed only 200 kilometers from Mercury's crater-riddled surface, closer than the two orbiters will operate once the mission begins in earnest.

The probe was taking images of the scorched planet during the flyby with its low-resolution monitoring cameras that are mounted on the spacecraft's transfer module. ESA released the first image about four hours after the closest approach, revealing large impact craters including a 120-mile-wide basin.

The two orbiters together carry 16 scientific instruments, but only about 60% of those were operational during the 48 hours around the closest approach, ESA's BepiColombo project scientist Johannes Benkhoff told. The rest, including high-resolution cameras, cannot be operated in the cruise configuration, as they are hidden either by the spacecraft's transfer module or its sunshield.

Benkhoff said the spacecraft's magnetometers and particle detectors were switched on during the flyby and will likely generate valuable scientific data about the solar wind in Mercury's vicinity.

During this flyby, BepiColombo approached Mercury from the night side, Benkhoff noted, which meant that imaging could only start 4 minutes after the closest approach, when the planet was sufficiently illuminated. By then, the probe was about 800 km away from Mercury's surface.

The images, which ESA plans to release within about a day, are expected to reveal craters and tectonic faults on Mercury's sunburnt surface.
@thewonderofspace Open / Comment

2022-06-23 18:17:11 Mercury-bound spacecraft whizzes past the smallest planet for the 2nd time

@thewonderofspace Open / Comment

2022-06-23 13:41:48 Open / Comment

2022-06-23 13:41:08 Open / Comment

2022-06-23 13:40:01 Open / Comment

2022-06-23 13:38:59 Open / Comment

2022-06-23 13:38:12 Open / Comment