#37: - Dance of the Holiday Planets - Martian Dust Devil Video/Audio - & 2 more
TGT 12/17/22: Sky Planning Calendar--Inner Planet Holiday Show, Moon Visits All but One Evening Planet, Circumpolar Meteors; This Just In--Multiple Star Crimes, Sound/Video of a Mars Dust Devil
Cover Photo - Evening Twilight Skies Near the Holidays
In This Issue:
Cover Photo — Evening Twilight Skies Near the Holidays
Welcome to Issue 37!
This Just In -
- When A Member of Your Family Commits a Messy Crime….
- The (Dust) Devil You Say!Sky Planning Calendar —
* Moon-Gazing - The Moon Ends the Year Visiting the Evening Planets, Save One
* Observing—Plan-et - Mercury and Venus’ Christmas Show (Cover Story)
* Border Crossings - Sagittarius is the Seasonal Solstice HomeThe Galactic Times — InDepth Inbox Magazine #2 Preview (It’s Available)! - What IS Above Us?
The Classroom Astronomer Issues 41 & 42 Highlights
Welcome to The Galactic Times Newsletter-Inbox Magazine #37 !
Just want to toot our own horns….but after a year and a half of publication, on Substack, The Galactic Times ranks as the #6 astronomy newsletter! The Classroom Astronomer is #2!!
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Mars and Jupiter may be glowing brightly this holiday season, and easier to find, but the best planetary show is in the evening twilight, with Mercury and Venus shouting for attention. See details in the Sky Planning Calendar, and give those gifts of telescopes or binoculars one day earlier.
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Publisher — Dr. Larry Krumenaker Email: newsletter@thegalactictimes.com
This Just In
* When A Member of Your Family Commits a Messy Crime….
It is fairly understood in stellar evolution that at some stage of some red-giant stars’ lives, they eject their outer atmospheres and become planetary nebulae, those beautiful but short-term ephemeral shells. We think of planetaries as those baubles of spherical gas that are only opaque enough on their edges to be seen as donut-shaped rings, a la Lyra’s Ring Nebula. But the usual picture is that of a single star going through this phase, perhaps one with some planets. No astronomy textbook ever discusses what happens when the nebula is formed in a star system with more than one star in it. Considering that many stars are indeed in binary systems, at least, it is an overlooked scenario.
Which makes the early James Webb Telescope observations of the so-called Southern Ring Nebula NGC 3132 an interesting anomaly of a planetary nebula. For one thing, it is hardly a ring-like or symmetrical nebula. It is a dramatic mess.
It has been long known to have not a central star but a central binary, already a source of suspicion for making it a non-circular object. But when observed in molecular hydrogen light instead of atomic light, the nebula takes on a wild, messy, appearance of arcs and radiating light spikes, and extra halos. JWST finds a hot inner disk of dust enveloping the inner star of the binary, which is overheated, indicating there is at least one more star in the system.
The authors of the research, Orsola de Marco and 68 others, with perhaps tongue very much in cheek, summarize what has happened here as a murder plot and the planetary nebula as the crime scene: “The A-type companion could not have partaken in the interaction that unravelled the AGB (Asymptotic Giant Branch) star, but was (and is) certainly present. A second companion at 40–60 AU left an indelible trail of its presence in the form of arcs, but was not close enough to generate the dusty disk, nor shape the ionized cavity, implying that there must have been at least another accomplice. This points the finger at a close-by companion that is either avoiding detection or has perished in the interaction (merged). If the numerous protuberances seen in the ionized cavity come in pairs, then tumbling jet axes would be needed and this would point the finger to the presence of a second, close companion, which would make the system a quintet. Even ignoring the putative second, close companion, we can state with good degree of certainty that the system is at least a quartet. Systems of four or five stars orbiting within a few ×1,000 AU are not impossibly rare for primary stars in the progenitor mass range of interest here (for example, HD 104237); indeed, present estimates indicate that 50% or more of stars of 2–3 M⊙ are in multiple systems, and of order 2% of A-type stars have four companions.” [The Messy Death of a Multiple Star System and the Resulting Planetary Nebula as Observed by JWST. Nature Astronomy, 6, pages 1421–1432. December 8, 2022. https://doi.org/10.1038/s41550-022-01845-2.]
* The (Dust) Devil You Say!
The next best thing to being on Mars is to have a robot emissary with a camera and a microphone to relay the conditions back to you!
Here, courtesy of the Perseverance mission is the sight and sounds of a Martian Dust Devil coming straight at and over the robotic probe. Estimated to be 110 meters high and 25 meters wide (more than Perseverance itself, it struck the rover in September 2021 and the video and audio was just released by NASA, and published and analysis released through Nature Communications journal on December 13. This was the first time the sound of a dust devil on Mars, an otherwise common occurrence there, had been obtained. Dust devils contribute to the degradation of equipment there so it is important to understand how they work in order to protect future probes, and habitats.
[N. Murdoch et al, The Sound of a Martian Dust Devil. (2022). Nature Communications, 13, Article number: 7505, December 13. DOI: 10.1038/s41467-022-35100-z]
Sky Planning Calendar
Moon-Gazing
Moon passages by a star, planet or deep sky object are a good way to find a planet or other object if you’ve never located it before.
View or Download this information on our Sky Event Online Calendar on The Galactic Times homepage!
December 23 New Moon
December 24 Perigee. The thin, pretty Moon in the evening twilight is also about as large as it can get, a Super Christmas Eve Waxing Crescent! Enjoy. Also nearby is Mercury 4-degrees to its North and even brighter Venus 3-degrees to the Moon’s North. A pretty trio to watch with your new holiday binoculars?? (See the Cover Photo for this night and the next five.)
December 26 Saturn gets its turn to be 4-degrees North of the passing Moon.
December 29 First Quarter Moon. And Jupiter is in the year’s last Moon-Planet conjunction, 2-degrees apart.
Observing---Plan-et
Mercury dances around Venus in the twilight glow but a low horizon can make it easier to observe, and binoculars even better. On the 21st Mercury is at its Greatest Elongation (angular distance) from the Sun, shining at a brilliant magnitude -0.6, but the best night to observe it might be Christmas Eve, the 24th, when A) Mercury is at its highest in the early evening twilight, B) and it is near Venus, a brilliant sky-mark, and C) the big, thin ONE-DAY-OLD Moon is near them both. Fading daily, some three-four days later (27-28th) Mercury is straight above Venus, on the 29-30th, Venus is to Mercury’s direct left (again, see the Cover Photo for maps). On the 29th they are closest, only 1.4 degrees apart and Mercury has dimmed more than a full magnitude, to +0.9 in 8 days.
Heading eastward, Saturn is the dimmest planet (save Mercury on the last day of the month) at magnitude +0.8. Find it in a neat equilateral triangle with two stars of the constellation Capricornus near the Moon near New Year’s Eve. Interestingly, its disk is the same size as Mars’ on that last day of the month even though in miles Mars is much the dwarf. That’s what being only a bit more than a half Astronomical Unit from us (Mars) compared to Saturn’s 10 AU from us does to your appearance. It also makes Mars brighter, magnitude -1.6.
Jupiter is high in East once the Sun sets, brightest thing in the sky but for the visiting First Quarter Moon, once Venus sets early.
Northern Hemisphereans on Earth get a lower rain of photons (well, lower density per square mile) on December 21st when the Solstice occurs, at 3:48 PM US Central Time. It gets an even smaller rain….of meteors….the next evening, when the Ursids meteor shower peaks at 4PM. Given that that occurs near sunset and the shower lasts about half a day, and Ursids come from near Ursa Minor, the Little Bear, well above the northern horizon for most Northern Hemisphereans, you might actually get to see some shooting stars as a pre-Christmas fireworks display from the tail end of the shower which lasts 12 hours before and after the peak—if you count up to 10 per hour as fireworks.
Border Crossings
No coordination with the holidays, or calendars, here. The Sun has been in Ophiuchus, the Serpent Bearer, for some time, but re-enters the traditional zodiac constellations, specifically Sagittarius, on December 18th. The horoscope column has it in Sagittarius already….and leaving it on the 22nd for Capricornus. An overlap of correctness for four days…..
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The Classroom Astronomer Newsletter - Inbox Magazine #41
#41 - Sky Lessons with a Comet and Jupiter's Moons - AstroEDU Teacher's Resource with 2 Samples [Free Post]
Cover Photo - Comet 2022 E3 (ZTF)
Welcome to Issue 41!
- We’re #2! We’re #2!
- The Solstice Sun is LOOOOW…So is Our Solstice Subscription Offer!Sky Lessons
- Comet ZTF (Cover Story)
- Jupiter’s Moons and Kepler’s Third LawConnections to the Sky/Astronomical Teachniques
- IAU Shaw: AstroEDU Resources for Teachers
- Make Your Own Sun (from Colombia)
- Powers of Ten (from India)
The Classroom Astronomer Newsletter - Inbox Magazine #42
#42 - Uncovering Hidden Data in a Light Curve - How to Mine Gaia's Star Data - & 3 more [Paid Post]
In This Issue:
Cover Photo - Light Curve Hidden Treasures
Welcome to Issue 42!
Astronomical Teachniques - Searching Gaia
Connections to the Sky
- NASA’s UNITE Citizen Science Project Seeks Telescope Users
- Using Astronomy to Teach About Climate Change
- ISS Water DropsThe RAP Sheet: Research Abstracts for Practitioners
- What Hides Within a Photograph: Analysis of a Light Curve in the Classroom (Cover Story)Highlights from the Other Hermograph Newsletters
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