#24K - Star Clusters Clear the Way for the Sun - Runaway in the Neighborhood - Space Balls Live - Solstice and More - & Mercury and Saturn in View, or Not
TGT 6/16/24: Star Clusters Create Star Clusters, Clearing Out Dust; Runaway Nearby Star; Food from Beyond the Asteroids; Evening Twilight Gets Interesting; Saturn May Disappear; Solstices and Dates
Cover Photo - The Cluster That Births Clusters
In This Issue:
Cover Photo — The Cluster That Births Clusters
Welcome to Issue 24K!
Sky Planning Calendar —
* Moon-Gazing - Moon Sails Over Saturn, If You Are Lucky
* Observing—Plan-et -
- Saturn and Mercury Enter the Evening Sky; Find Mercury Lined Up With Twins.
* Border Crossings - Proof Astrology and Astronomy Aren’t Twins….Astronomy in Everyday Life - Space Balls Lives!
This Just In
* AAS: Why Is There No Dust in the Sun’s Way? (Cover Story)
* AAS: Runaway Dwarf in our Neighborhood
Welcome to The Galactic Times Newsletter-Inbox Magazine #24K!
This Issue may be a bit shorter than usual, mostly because I have just completed my virtual attendance at the American Astronomical Society (AAS). Also, the July 1st issue may be delayed as I will be between TWO European week-long virtual conferences AND in between them, I will be on a short jaunt to do a speaking gig in Georgia over that weekend.
In Observing-Plan-et, Saturn crosses into being an Evening planet but…can you find Saturn on the 27th? The Moon may hide it from you! You can find Mercury entering the Evening dusk and it lines up with the Gemini Twins stars.
The Earth reaches the point in its orbit where the Sun stands still, a solstice, but the Longest Day, the earliest and latest Sunrises/Sets and Twilights, don’t happen on June 21st!
For fun, do you remember the sci-fi comedy Space Balls? Apparently so does one food company and bumper sticker printer. See Astronomy in Everyday Life.
This Just In: First reports from that aforementioned AAS meeting, about the dust (or lack of in spots) in our Solar Neighborhood, and the source of some of the star clusters involved is visible in our early summer skies.
Also, in our neighborhood is a faint star that may actually escape the Milky Way!
Other reports will be going out to paid subscribers. Annual subscribers pay roughly $1.25 per Galactic Times Issue. Your support is very welcome; you get extra issues that lower that cost! Subscribe with the button below.
Enjoy!
Publisher — Dr. Larry Krumenaker Email: newsletter@thegalactictimes.com
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.
June 16 Spica will be shining its blue-white light 1.2-degrees below the Moon.
June 20 The red giant Antares will be even closer to the Moon on this night, 0.3-degrees, less than the Moon’s diameter.
June 21 Full Moon, riding low, in fact, the southernmost Full Moon of the year, just above the spout of the Teapot, a.k.a. Sagittarius. Passes close to M6 (hint: See Cover Story).
June 27 Perigee, the Moon’s closest point in its orbit to Earth. This slightly larger than average Moon passes achingly close to the Ringed Planet Saturn, about 0.08 degrees South of the Moon Can you catch them together in your telescope? If you are in the Southern Hemisphere, you can’t see Saturn at closest approach; it will be behind the Moon, occulted.
June 28 Last Quarter
Observing---Plan-et
==Sun Reaches Solstice but Earliest/Latest Rises and Sets Don’t Coordinate==
==Mercury Meets Twins in a Line-Up, and Saturn reaches Evening Planet Status==
The Sun reaches its summer (Northern Hemisphere, winter in the Southern) solstice on June 21st, at 3:51 PM Central Daylight Time. Because of orbital and revolution dynamics, that solstice date this year nearly coincides with the longest (N.H.) day—on the 20th--but NOT the dates of earliest sunrises or latest sunsets, or twilight starting or endings! On the 13th we had THE EARLIEST Sunrise. On the 17th we have the earliest morning twilight start. Then the longest day and solstice. Then, evening maximums go in reverse order—latest evening twilight on the 24th, latest Sunset on the 27th, nearly a week after the Solstice. All because of the variability of Earth’s orbital speed versus its rotational constant speed, with a bit of Earth’s tilt thrown into the mix.
Mercury is rising into the Northern Hemisphere evening twilights, following solar conjunction two days ago. After the 21st it will be up until at least 45 minutes after the Sun sets, into much of July, too. A good day to see it would be the 29th when it makes a straight line with the Gemini Twin stars, Castor and Pollux, low in the twilight glow. It will be the brightest of the three, on the line’s left end, at magnitude -0.6, among the brightest objects otherwise in the sky.
Venus. It has entered the evening sky but still cloaked in deep twilight. Finally lazes more easily into view….in July.
Mars rises before morning twilight and up to two hours after Saturn.
Jupiter rises before Sunrise more than 45 minutes before the Sun gets up. By the end of the month it is rising just over a full hour before lazy ol’ Sol, and at the start of morning twilight. Thus it begins to be a dark-sky planet in July.
Saturn, another half month, another gain of an hour earlier to rise. It is very late at night for it but it is now an evening planet, rising midnight DST and earlier each night.
Border Crossings
Same day, different interpretations. The Sun is in Taurus until the 20th when it crosses into Gemini where it has its solstice moment. At that exact date, the horoscopes say it LEAVES the sign of Gemini! So much for accuracy.
Astronomy in Everyday Life
Space Balls Lives!
Food is a popular venue for astronomical names. Browsing for something else in a World Market store, I came across this pair of snacks from beyond the Asteroid Belt:
While I was doing some recycling, another patron of the center did their thing and as they were turning around, I saw this and with permission, took the photo.
I am told it was first done as a bumper sticker in the sci-fi spoof of Star Wars, called…. Space Balls. I have not checked the video yet.
This Just In
AAS: Why Is There No Dust in the Sun’s Way?
Some folks have really dusty homes. There are places where the dust is pretty thick, yet other places where there might be surprisingly little. Part of the reason is that winds blow dust across open spaces and various obstacles cause eddies to trap the dust in larger amounts in their places.
The Galaxy is messy. Dust everywhere. Well, not quite everywhere. There are areas that haven’t got that much. Some of them around the Solar System. What caused them? And how can we find out where those winds came from?
The answer according Cameren Swiggum of the University of Vienna, in a session at last week’s American Astronomical Society meeting, is the wind pattern caused by supernovae explosions. But not just any random supernovae. Exploding stars from certain specific families of stars.
The Solar System, to within about 5000 parsecs (more than 16,000 light years) has numerous very small, very young star clusters. Hundreds of them. Yet if you go outside tonight and look up (preferably in a dark, unlit by street lights area) you won’t see the sky sparkling with hundreds of clumps of stars. But here is the thing….they can be found, many seen in even small telescopes, and their have been our neighbors for at least 30 million years. So why would a bunch of stars cause gaps in the dust near the Sun?
Star clusters stars are all formed at the same time in large interstellar nurseries. But star clusters, like children, leave the home eventually. In fact, gravitationally, they have to; there isn’t enough pull between them to prevent the baby cluster from being slowly ripped apart by tidal effects of their revolution around the Galactic Center. Like wherever our Sun came from, all its siblings have been pulled away from the original family group, that cluster stretched like gum or taffy until there is nothing but wandering stars, often binaries, but not always (Hint: See big bright yellow thing in day sky).
Another thing happens. There are multiple sizes of stars in these star clusters (back then and now). The bigger ones are bright, flashy, stand out from their siblings….until they die…in supernovae. The winds of supernovae can be fast and furious and not only blow their own atmospheres away but also the gas and dust in the area. They also can disrupt the clusters they were traveling in.
If we can’t look up and see them, how do we find them? The ESA satellite mission Gaia is the key. Millions of stars are being mapped, and their 3-D positions and velocities determined. In doing so, a lot of stars may have the same values, indicating that they are related to each other. Ipso facto—star clusters. According to Swiggum, there are 155 such young star clusters running in a rough line through the Sun’s position.
When the more massive stars of these clusters ran out of nuclear fuel, Boom! They spread their atmospheres and the nearby dust away creating the gaps in the dust. More supernovae? More dust goes out of the neighborhood.
An interesting thing, though. These 155 clusters aren’t just….traveling in our neighborhood, in random motions. Remember that stars spread out of the clusters over time, and the nearby young star clusters themselves, at least many if you trace their galactic paths backwards in time, apparently come together in larger clumps. Three to be precise. Apparently not only the stars form cluster families, but the cluster families come from larger ‘pods’.
Swiggum found there were three main stellar cluster families that cause clusters to surround the Solar System, clearing the dust away around us. All three come from star clusters you CAN see with the naked eye. Messier 6 (M6) in Scorpius, the Alpha Persei cluster scattered all over the (mainly) Fall sky, and Collinder 135, a cluster in the southern constellation of Puppis. As they aged, young star clusters formed, traveled away, had family members die and blow away some of the surrounding dust around … us. View the location of M6 in the June sky on our Cover Photo.
AAS: Runaway Dwarf in our Neighborhood
As if to make the above scenario more clear, Adam Burgasser of the University of California reported on a nearby Brown Dwarf shooting through our solar neighborhood. If you consider 400 light years as in our neighborhood.
What you must also keep in mind is that this star is moving at an incredible 456 km/sec, roughly 0.1% the speed of light. Might not seem like much to you but compared to our Sun’s speed, a generally good average for most other stars, of around 200 km/sec, this is high speed.
In the above photos you can see the dim object obviously shifting its position over a decade and a half.
The Brown Dwarf, J1249+3621, a small cool (less than 2000-degrees), very faint object also turns out to be very poor in cosmic metals (generally everything heavier on the Periodic Table than Helium), only about 5% of solar abundances. This puts it in the L-class dwarf category.
What is the puzzle is why does such a tiny, cool, poor dwarf has such speed that it could literally escape the Milky Way galaxy? There are three reasons, all of which possible, all of which unproven.
It is the remnant of a supernova, the stars of which are often binaries. Once there was no star to orbit, per basic physics of Newton, it flew off straight away with possibly some extra kick.
It might have been scattered passing by a black hole, similar to how NASA sends probes to planets and saves fuel by having them slingshot around other planets, changing the probe’s direction and adding speed.
It wasn’t ours to begin with. It came from one of the main small fluffs of satellite galaxies around the Milky Way. These often do pass through the main galaxy and get dispersed and broken up. This could be a remnant of one of them.
One last thing to note—this object was first detected by citizen scientists, nearly 100,000 of whom have been scanning data from the WISE spacecraft in its various forms looking for fast moving faint objects that are in our solar neighborhood. They are also hoping to find what is called Planet 9, a hypothetical extremely distant and faint companion to the Sun.
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More Reports from the AAS will be sent out shortly to paid subscribers. Among the stories being worked on include those on stellar disks, both old and young, the fates of atmospheres and oceans on exoplanets, stars near the Sun marked for exploration for habitable zones around them, some citizen science studies during the recent solar eclipses, and the variable brightness of the Sun. Didn’t know it was a variable star? Upgrade to a Paid or Educator Subscription!