{"id":7687,"date":"2024-01-06T00:01:00","date_gmt":"2024-01-06T00:01:00","guid":{"rendered":"https:\/\/brendans-island.com\/catholic-citizen\/?p=7687"},"modified":"2024-01-06T16:48:54","modified_gmt":"2024-01-06T16:48:54","slug":"colliding-planets-near-asassn-21qj-maybe","status":"publish","type":"post","link":"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/","title":{"rendered":"Colliding Planets Near ASASSN-21qj: Maybe"},"content":{"rendered":"\n<p><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#asassn\"><img data-recalc-dims=\"1\" decoding=\"async\" align=\"right\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-Sketch-of-the-hypothesis-for-the-observations-seen-towards-ASASSN-21qj-At-t0-the-329.jpg?w=640&#038;ssl=1\" alt=\"Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen's sketch, showing their hypothesis for the observations of ASASSN-21qj (2MASS J08152329-3859234). Matthew Kenworthy et al., Nature. (October 2023)\"><\/a>They were looking for supernovae.<\/p>\n\n\n\n<p>What they found may become a double planet, like the Earth-Moon system, once it cools down.  Or a planet with a giant moon, again like the Earth-Moon system.<\/p>\n\n\n\n<p>Then again, an oddly-uneven dusty disk may be orbiting this young, very &#8220;Sun-like&#8221; star. Either way, ASASSN-2qj is much more interesting than it was a few years back.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#barycenters\"><strong>Barycenters and Binaries: Briefly<\/strong><\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#rabbit\"><strong>Rabbit Holes and an &#8216;Assassin Star&#8217;<\/strong><\/a>\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#professional\">Professional Scientists, Amateur Astronomers, Teamwork and Twitter\/X<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#soslow\">&#8220;&#8230;So Slow Smart&#8221;<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#asassn\"><strong>ASASSN-21qj: Once Obscure, Now Intriguing<\/strong><\/a>\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#very\">A <em>Very<\/em> Sun-Like Star<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#uncertainty\">Uncertainty and Science<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#star\"><strong>&#8216;&#8230;A Star to Steer By&#8230;&#8217;<\/strong><\/a><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-black-color has-alpha-channel-opacity has-black-background-color has-background is-style-wide\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><a name=\"barycenters\"><\/a>Barycenters and Binaries: Briefly<\/h3>\n\n\n\n<p><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/one-small-step-in-a-long-journey\/\"><img data-recalc-dims=\"1\" decoding=\"async\" align=\"right\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20190630ff\/20190718-as11-44-6552-trim-329.jpg?w=640&#038;ssl=1\" alt=\"Apollo 11\/NASA photo: Earth rising over the Moon's horizon (Smyth's Sea on the Lunar nearside). (July 1969)\"><\/a>I suspect one reason scientists generally call Earth and Earth&#8217;s moon a planet and its satellite is that we live on Earth and have been thinking of the Moon as \u2014 well, as the moon \u2014 since long before we started thinking about the plan\u0113tai, planets, as other worlds.<\/p>\n\n\n\n<p>Another reason may be that the center of mass for the Earth-Moon system is about a thousand miles below Earth&#8217;s surface.<\/p>\n\n\n\n<p>&#8220;Barycenter&#8221; is a fancy word for center of mass. It&#8217;s the point that two objects, like Earth and Moon or Jupiter and our Sun, orbit around.<\/p>\n\n\n\n<p>The Jupiter-Sun barycenter is a little more than 28,000 miles above the Sun&#8217;s surface. But we don&#8217;t call the Sun-Jupiter system a binary star. Mostly because Jupiter isn&#8217;t a star: although if it was thirteen times more massive, it would be: a brown dwarf.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#1\">1<\/a><\/sup><\/p>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-black-color has-alpha-channel-opacity has-black-background-color has-background is-style-wide\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><a name=\"rabbit\"><\/a>Rabbit Holes and an &#8216;Assassin Star&#8217;<\/h3>\n\n\n\n<p><iframe loading=\"lazy\" title=\"YouTube video player\" src=\"https:\/\/www.youtube.com\/embed\/baO3OVJ66CQ?si=p4H3EvfAwqHcKqGh\" width=\"560\" height=\"315\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><br>(&#8220;<a href=\"https:\/\/youtu.be\/baO3OVJ66CQ?si=lzkfTfm8s1aXqPdS\n\">A planetary collision: ASASSN-21qj<\/a>&#8220;, Las Cumbres Observatory, YouTube (October 2023)<\/p>\n\n\n\n<p>An advantage <strong>and<\/strong> disadvantage of being my own editor is that I can go chasing after information, even if there&#8217;s a looming deadline.<\/p>\n\n\n\n<p>I&#8217;d noticed a piece in the Sky and Telescope February 2024 issue&#8217;s News Notes section. That&#8217;s right: February 2024, it&#8217;s only the first week of January, and that&#8217;s another topic.<\/p>\n\n\n\n<p>Anyway, the short article mentioned a &#8220;young, sun-like star&#8221; and colliding exoplanets. The situation sounded a great deal like a recent explanation for how the Earth-Moon system formed, which caught my attention.<\/p>\n\n\n\n<p>The article didn&#8217;t mention the star&#8217;s designation, but did include several names. That&#8217;s more than I sometimes have to start with. So by Tuesday, I&#8217;d learned that the star&#8217;s designation was,  for the scientists who&#8217;d noticed its odd behavior, ASASSN-21qj.<\/p>\n\n\n\n<p>And from that point on, every time I saw the star&#8217;s designation, I read it as &#8220;Assassin-Twenty-One-Que-Jay&#8221;. Why, I don&#8217;t know. Although my reading has included a fair fraction of pulp fiction, most of it was of the science fiction variety.<\/p>\n\n\n\n<p>Getting back to ASASSN-21qj and a probable planetary pileup.<\/p>\n\n\n\n<p>Before it was labeled ASASSN-21qj, it&#8217;d been 2MASS J08152329-3859234: and still is, for that matter. Its ASSASSN designation is (probably) mostly for folks working in and with the All-Sky Automated Survey for Supernovae (ASAS-SN) network.<\/p>\n\n\n\n<p>The ASAS-SN network collects and organizes data from 20 robotic telescopes,<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#2\">2<\/a><\/sup> and if I go off on that tangent I&#8217;ll never get this ready by Saturday.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a name=\"professional\"><\/a>Professional Scientists, Amateur Astronomers, Teamwork and Twitter\/X<\/h4>\n\n\n\n<p><a href=\"https:\/\/science.nasa.gov\/get-involved\/citizen-science\/amateur-astronomers-help-discover-cosmic-crash\/\"><img data-recalc-dims=\"1\" decoding=\"async\" align=\"right\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-e1edc30d7f86c5be16edae9a0bf4e5e0.gif?w=640&#038;ssl=1\" alt=\"Dan Caselden, NASA's animation: NASA Volunteer Arttu Sainio saw the star Asassn-21qj brightening, possibly due to crashing planets.\"><\/a>After I learned that I was looking for ASASSN-21qj, I found a NASA article that told how professional scientists, amateur researchers, and social media, went from speculation about something &#8220;weird&#8221; in a database to \u2014 oh, never mind.<\/p>\n\n\n\n<p>Sharing an excerpt will be easier than paraphrasing the article.<\/p>\n\n\n\n<p>But first, about that animation with what I assume are years and months displayed at the top.<\/p>\n\n\n\n<p>It&#8217;s from the NASA Science Editorial Team article, and I suspect it&#8217;s a series of images taken between 2010 and 2021. If that&#8217;s so, the black blotch in the middle is very probably ASASSN-21qj.<\/p>\n\n\n\n<p>And although the animated GIF&#8217;s caption says who made it, \u2014<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>&#8220;NASA Volunteer Arttu Sainio saw the star Asassn-21qj brightening, possibly due to crashing planets.<br>&#8220;Credit: Dan Caselden, NASA&#8221;<\/p>\n<\/blockquote>\n\n\n\n<p>\u2014 I&#8217;ve yet to learn when it was made, or where the data came from. Thursday afternoon I finally decided that its origins would remain a mystery.<\/p>\n\n\n\n<p>Here&#8217;s an overly-long excerpt from that NASA article. I&#8217;ve highlighted a few bits:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>&#8220;<a href=\"https:\/\/science.nasa.gov\/get-involved\/citizen-science\/amateur-astronomers-help-discover-cosmic-crash\/\">Amateur Astronomers Help Discover Cosmic Crash<\/a>&#8220;<br>NASA Science Editorial Team, <a href=\"https:\/\/science.nasa.gov\/citizen-science\/\">Citizen Science<\/a>, Get Involved With NASA, NASA (December 8, 2023)<\/p>\n\n\n\n<p>&#8220;&#8230;A recent paper in Nature describes how <strong>an international group of professional and amateur astronomers teamed up<\/strong> to measure the heat glow of two ice giant planets colliding and see the resultant dust cloud moving in front of the parent star several years later.<\/p>\n\n\n\n<p>&#8220;<strong>The story began back in 2021, when the<\/strong> All-Sky Automated Survey for Supernovae (<strong>ASAS-SN<\/strong>) network <strong>noticed that a Sun-like star<\/strong> 1800 light years away <strong>was rapidly fading. Some 30 days later, NASA volunteer Arttu Sainio was reading X (formerly Twitter), and caught professional astronomers Dr. Matthew Kenworthy and Dr. Eric Mamajek speculating about this weird event. Arttu decided to further investigate this star,<\/strong> called Asassn-21qj, on his own, using data from NASA\u2019s NEOWISE mission. Arttu was surprised to find that the star had demonstrated an unexpected brightening in infrared light two years before the optical dimming event. So he joined the talk on social media and shared his finding with the two astronomers.<\/p>\n\n\n\n<p>&#8220;<strong>&#8216;Out of the blue, amateur astronomer Arttu Sainio on social media pointed out that the star brightened up in the infrared over a thousand days before the optical fading,&#8217; said Kenworthy. &#8216;I knew then that this was an unusual event.&#8217;<\/strong><\/p>\n\n\n\n<p>&#8220;More contributions from amateurs helped determine the nature of the star. Amateur spectroscopist Hamish Barker tried to capture a spectrum of Asassn-21qj in late July, 2022. A spectrum spreads out the colors of the starlight, revealing the star&#8217;s temperature. However,<strong> the star turned out to be too dim, so Hamish asked Olivier Garde from a French amateur astronomy team if they could add ASASSN-21q to their target list<\/strong>. The team, called the Southern Spectroscopic project Observatory Team (or &#8216;2SPOT&#8217;), succeeded in collecting the needed spectrum in early September, 2022 and forwarded it Kenworthy. The 2SPOT team members are St\u00e9phane Charbonnel, Pascal Le D\u00fb, Olivier Garde, Lionel Mulato and Thomas Petit.<\/p>\n\n\n\n<p>&#8220;Two more amateur astronomers also independently observed the star and contributed their data to the study&#8230;.&#8221;<br>[emphasis mine]<\/p>\n<\/blockquote>\n\n\n\n<p>The point, one point at any rate, is that today&#8217;s information technology lets folks living on different continents share data and ideas as easily as folks living in the same neighborhood could, a generation or so back.<\/p>\n\n\n\n<p>I see that as a good thing.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a name=\"soslow\"><\/a>&#8220;&#8230;So Slow Smart&#8221;<\/h4>\n\n\n\n<p>I would have saved myself a lot of time, if I&#8217;d thought to check Sky and Telescope&#8217;s website. There&#8217;s another version of the &#8220;February 2024&#8221; article there, posted in October of last year: with a link to one of the scientists&#8217; Twitter\/X posts.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#3\">3<\/a><\/sup><\/p>\n\n\n\n<p>Since Matthew Kenworthy&#8217;s Twitter\/X post included the star&#8217;s designation (ASASSN-21qj), if I&#8217;d gone there first, I&#8217;d have saved most of a day&#8217;s search.<\/p>\n\n\n\n<p>As an old Norwegian-American said, &#8220;I get so quick old, and so slow smart&#8221;.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-black-color has-alpha-channel-opacity has-black-background-color has-background is-style-wide\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><a name=\"asassn\"><\/a>ASASSN-21qj: Once Obscure, Now Intriguing<\/h3>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\"><img data-recalc-dims=\"1\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-Sketch-of-the-hypothesis-for-the-observations-seen-towards-ASASSN-21qj-At-t0-the-658.jpg?w=640&#038;ssl=1\" alt=\"Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen's sketch, showing their hypothesis for the observations of ASASSN-21qj (2MASS J08152329-3859234). Collision happens at t\u2009=\u20090, producing a cooling and expanding cloud of debris. Material close to the (now hot) remnant is heated, generating the 1,000 K infrared emission. About 1,000\u2009days later, the expanding cloud crosses the line of sight between the star and the Earth, generating the observed optical light curve. Matthew Kenworthy et al., Nature. (October 2023)\"\/><\/a><figcaption class=\"wp-element-caption\">Matthew Kenworthy et al.&#8217;s sketch, showing how a synestia may have formed near ASASSN-21qj. (2023)<\/figcaption><\/figure>\n\n\n\n<p><a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\"><img data-recalc-dims=\"1\" decoding=\"async\" align=\"right\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-ExtendedDataTable1PropertiesofASASSN-21qj-165.jpg?w=640&#038;ssl=1\" alt=\"Kenworthy et al.'s Extended Data Table, stellar properties of ASASSN-21qj (Gaia DR3 5539970601632026752, 2MASS J08152329-3859234). Nature (October 2023) via arXiv\"><\/a>After I had one of the star&#8217;s designations, ASASSN-21qj, I could start checking out just what various discussions of it meant by &#8216;sun-like&#8217;.<\/p>\n\n\n\n<p>Along the way, I learned that ASASSN-21qj is Gaia DR3 5539970601632026752 in the Gaia Data Data Release 3, and I&#8217;m drifting off-topic again.<\/p>\n\n\n\n<p>Previous experience told me that &#8216;sun-like&#8217; could mean anything from a G2V star that&#8217;s about four and a half billion years old, to simply a star that&#8217;s on the main sequence.<\/p>\n\n\n\n<p>Happily, I found what I needed in a pre-publication copy of that Nature paper. The &#8220;2SPOT&#8221; researchers, mentioned in that NASA article, found that light from ASASSN-21qj &#8220;is consistent with being a G2 type dwarf star&#8221;.<\/p>\n\n\n\n<p>Normally, I&#8217;d go off on a tangent about stellar evolution: but it&#8217;s now Friday afternoon. Long story short, looks like ASASSN-21qj is very much like our Sun, but much younger: 300,000,000 years old. Give or take 92,000,000.<\/p>\n\n\n\n<p>That makes ASASSN-21qj and its probable planets about as old as the Solar System was; when our Sun had settled onto the main sequence, but the planets were still playing bumper cars.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#4\">4<\/a><\/sup><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a name=\"very\"><\/a>A <em>Very<\/em> Sun-Like Star<\/h4>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\"><img data-recalc-dims=\"1\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/202401025-Simulations-of-the-formation-of-a-post-impact-body-Giant-impacts-between-super-Earths-and-658.jpg?w=640&#038;ssl=1\" alt=\"Matthew Kenworthy et al's extended data: simulations of impacts between super-Earths and mini-Neptunes, which can produce post-impact bodies hundreds of Earth radii across. Except for the lower-right panel, particles are colored by their material (forsterite, water or a H2\u2013He mixture moving outwards in the initial bodies) and whether they came from the impactor or target (see top-left panel). The final two panels show only the mass bound to the primary remnant, which has 48.4\u2009times Earth's mass. In the last panel, particles that are at the simulation's minimum density are colored in green. Nature (October 2023) via arXiv\"\/><\/a><figcaption class=\"wp-element-caption\">From Matthew Kenworthy et al.&#8217;s simulation of collision between super-Earths and mini-Neptunes. (2023)<\/figcaption><\/figure>\n\n\n\n<p>What had caught my attention about discussions of this &#8220;young, sun-like star&#8221; was the probable planetary collision: which sounded like giant-impact hypothesis for how the Earth-Moon system began.<\/p>\n\n\n\n<p>Turns out, ASASSN-21qj <strong>might<\/strong> have a terrestrial planet, orbiting in its habitable zone. It might even have a churning filled doughnut of planet-stuff that&#8217;ll become Earth-Moon 2.0.<\/p>\n\n\n\n<p>But that&#8217;s not what the scientists have been studying.<\/p>\n\n\n\n<p>What&#8217;s been making ASASSN-21qj flare in the infrared and dim in visible light may have been two &#8220;two ice-giant type exoplanets of several to tens of Earth masses&#8221;, as a Wikipedia page says.<\/p>\n\n\n\n<p>What the scientists <strong>said<\/strong> was that the two probable planets were massive enough to be ice giants like Uranus and Neptune.<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>&#8220;\u2026an infrared brightening consistent with a blackbody temperature of 1000 K and a luminosity of 4% of that of the star lasting for about 1000 days, partially overlapping in time with a complex and deep wavelength-dependent optical eclipse that lasted for about 500 days. These observations are consistent with a collision between two exoplanets of several to tens of Earth masses at 2-16 au from the central star\u2026.&#8221;<br>(&#8220;<a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\">A planetary collision afterglow and transit of the resultant debris cloud<\/a>&#8220;, Summary paragraph; Matthew Kenworthy et al. (2023) via arXiv)<\/p>\n<\/blockquote>\n\n\n\n<p>That distance from ASASSN-21qj is two to 16 astronomical units. One au (or AU \u2014 capitalization varies) is how far Earth is from our Sun &#8211; roughly. It&#8217;s complicated, it&#8217;s now mid-afternoon Friday, so I&#8217;ll move along.<\/p>\n\n\n\n<p>Mars is very roughly one and a half AU out and the asteroid belt goes from 2.3 to 3.3 AU, so even if ASASSN-21qj&#8217;s probable planetary collision involved something like what became the Earth-Moon system, habitable it won&#8217;t become.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#5\">5<\/a><\/sup><\/p>\n\n\n\n<p>If it&#8217;s 16 AU out, that&#8217;d make it only slightly less distant from ASASSN-21qj than Uranus is from the Sun. So &#8220;ice giants&#8221; isn&#8217;t an unreasonable term for the planets. Probably.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><a name=\"uncertainty\"><\/a>Uncertainty and Science<\/h4>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\"><img data-recalc-dims=\"1\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-Optical-and-infrared-photometry-of-ASASSN-21qj-a-Normalized-optical-photometry-from-658.jpg?w=640&#038;ssl=1\" alt=\"Matthew Kenworthy et al.: 'Optical and infrared photometry of ASASSN-21qj. a, Normalized optical photometry from ASAS-SN in the V -band and the g\u2032 band. b, Fractional flux increase in brightness of ASASSN-21qj in both the W 1 and W 2 bands, for which a value of 1.0 represents the stellar contribution alone. c,Calculated NEOWISE color temperature estimated from the photometry of the two bands. The color temperature is plotted as zero when there is no infrared excess and is consistent with a temperature of 1000 K while the excess is present. Error bars are shown at 1\u03c3 confidence.' Nature. (October 2023) via arXiv\"\/><\/a><figcaption class=\"wp-element-caption\">Matthew Kenworthy et al.&#8217;s chart of visible and infrared light from ASASSN-21qj. (2023)<\/figcaption><\/figure>\n\n\n\n<p>I&#8217;ve said &#8220;probably&#8221; a lot, and you&#8217;ll find phrases like &#8220;observations are consistent with&#8221; in a great many scientific papers.<\/p>\n\n\n\n<p>That&#8217;s because, however sure they are about their data and analysis, scientists generally acknowledge they don&#8217;t know everything. That&#8217;s been my experience, at any rate, reading what they&#8217;ve written, and looking through their research.<\/p>\n\n\n\n<p>As for me? Well, I enjoy knowing stuff, and like getting my facts straight. But I figure that &#8220;observations are consistent with&#8221; means that something <strong>may<\/strong> be so. But that the &#8220;something&#8221;, whatever it is, may <strong>not<\/strong> be so.<\/p>\n\n\n\n<p>My guess is that scientists will be taking closer looks at ASASSN-21qj for years. Centuries, very likely, given how long conditions in the star&#8217;s vicinity may be changing:<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>&#8220;&#8230;The team acknowledges that <strong>it\u2019s possible the infrared brightening and the starlight blockage were in fact two separate events, but they make the case that two such events would be even more rare than a planetary-scale collision.<\/strong><\/p>\n\n\n\n<p>&#8220;Their calculations show that such a collision would vaporize both worlds, with a relatively small amount escaping to orbit the star. <strong>&#8216;Over the next few orbits (around a few hundred years), the dust will smear into a ring around the star,&#8217;<\/strong> Kenworthy explains. For now, the debris is in a long, giant cloud a quarter of an a.u. in size, and the dust is thick enough to block much of the star&#8217;s light as the cloud passes in front of it.<\/p>\n\n\n\n<p>&#8220;Most of the mass, though, has remained gravitationally bound, albeit in vaporized form. <strong>Team member Simon Lock (University of Bristol, UK) has previously proposed that such remnants might take the shape of a synestia, a donut-shape cloud with a bit of material straddling the middle (perhaps more akin to an extremely puffy Danish). This collision gives the researchers an opportunity to test that idea.<\/strong>&#8230;<\/p>\n\n\n\n<p>&#8220;&#8230;<strong>Another team,<\/strong> led by Jonathan Marshall (Academia Sinica Institute of Astronomy and Astrophysics, Taiwan), has <strong>published a different explanation in the Astrophysical Journal, suggesting instead that an uneven dusty disk surrounds the star, perhaps originating in the breakup of comets.<\/strong> That team notes a marked similarity between this system and the curious Boyajian&#8217;s Star&#8230;.&#8221;<br>&#8220;<a href=\"https:\/\/skyandtelescope.org\/astronomy-news\/two-worlds-have-ended-in-a-planetary-collision-and-a-new-one-has-begun\/\">Two Worlds Have Ended in a Planetary Collision \u2014 and a New One Has Begun<\/a>&#8220;<br>Monica Young, Sky and Telescope (October 12, 2023)<br>[emphasis mine]<\/p>\n<\/blockquote>\n\n\n\n<p>Boyajian&#8217;s Star, by the way, is KIC 8462852, informally called Tabby&#8217;s Star, and that&#8217;s something I talked about back in 2016.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#6\">6<\/a><\/sup><\/p>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-black-color has-alpha-channel-opacity has-black-background-color has-background is-style-wide\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><a name=\"star\"><\/a>&#8216;&#8230;A Star to Steer By&#8230;.&#8217;<\/h3>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/Argo_Navis\"><img data-recalc-dims=\"1\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-Argo_Navis_Hevelius-658.jpg?w=640&#038;ssl=1\" alt=\"Johannes Hevelius' constellation of Argo Navis, from his 'Uranographia' celestial catalog. (1690)\"\/><\/a><figcaption class=\"wp-element-caption\">Argo Navis: a huge constellation in Johannes Hevelius&#8217; &#8220;Uranographia&#8221;. (1690)<\/figcaption><\/figure>\n\n\n\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/Puppis\"><img data-recalc-dims=\"1\" decoding=\"async\" align=\"right\" src=\"https:\/\/i0.wp.com\/brendans-island.com\/blogsource\/20231112ff\/20240102-476px-Puppis_IAU-Puppis-ASASSN-21qj-329.jpg?w=640&#038;ssl=1\" alt=\"\"><\/a>Light from ASASSN-21qj traveled 1,850 years before reaching Earth.<\/p>\n\n\n\n<p>The star isn&#8217;t the only more-or-less-Sun-like star orbited by unexpectedly-warm dust, but it&#8217;s the only one I know of where scientists have &#8216;before and after&#8217; observations from what&#8217;s probably a planetary collision.<\/p>\n\n\n\n<p>No wonder at least two teams have crunched data and published papers. Despite ASASSN-21qj being so far away.<\/p>\n\n\n\n<p>ASASSN-21qj is in the general direction of Zeta Puppis, Naos, a whacking great overly-hot star that&#8217;s been studied a great deal more that the &#8216;assassin star&#8217; \u2014 and that&#8217;s yet another topic.<\/p>\n\n\n\n<p>Both stars are in the southern constellation Puppis, which we got when de Lacaille split up the ancient Argo Navis: which may go back to Sumerian times.<sup><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/#7\">7<\/a><\/sup> Or may not. Scientists aren&#8217;t the only ones who don&#8217;t know everything. \ud83d\ude09<\/p>\n\n\n\n<p>And that&#8217;s yet again another topic: also my cue to stop  writing, start proofing this thing, and add the usual links:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/double-jupiters-a-jumbo-puzzle-antimatter-falls-down\/\">Double Jupiters, a JuMBO Puzzle; Antimatter Falls Down<\/a>&#8220;<br>(October 7, 2023)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/trappist-1-and-the-mysterious-pea-pod-planets\/\">TRAPPIST-1 and the Mysterious Pea Pod Planets<\/a>&#8220;<br>(April 8, 2023)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/exoplanets-dust-and-who-sees-data-first\/\">Exoplanets, Dust, and Who Sees Data First?<\/a>&#8220;<br>(February 11, 2023)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/\">Earth&#8217;s Moon: Heat, Stir \u2013 \u2013 \u2013<\/a>&#8220;<br>(November 5, 2018)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/tides-and-our-moons-origin\/\">Tides and Our Moon&#8217;s Origin<\/a>&#8220;<br>(December 9, 2016)<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-text-color has-black-color has-alpha-channel-opacity has-black-background-color has-background is-style-wide\"\/>\n\n\n\n<p><sup><a name=\"1\"><\/a>1<\/sup> More than you need, or may want, to know about:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wikipedia\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/4_Vesta\">4 Vesta<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Barycenter_(astronomy)\">Barycenter (astronomy<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Binary_star\">Binary star<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Binary_asteroid\">Binary asteroid<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Ceres_(dwarf_planet)\">Ceres (dwarf planet)<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Classical_planet\">Classical planet<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Double_planet\">Double planet<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Dwarf_planet\">Dwarf planet<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Minor-planet_moon\">Minor-planet moon<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Moon\">Moon<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Planet\">Planet<\/a>\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Planet#History_and_etymology\">History and etymology<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Planetary-mass_moon\">Planetary-mass moon<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wide-field_Infrared_Survey_Explorer\">Wide-field Infrared Survey Explorer<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sjsu.edu\/faculty\/watkins\/centermass.htm\">Centers of Mass in the Solar System<\/a><br>applet-magic.com, Thayer Watkins, Silicon Valley &amp; Tornado Alley; San Jos\u00e9 State University, USA<\/li>\n\n\n\n<li><a href=\"https:\/\/pluto.jhuapl.edu\/Pluto\/The-Pluto-System.php\">The Pluto System<\/a><br>New Horizons, NASA&#8217;s Mission to Pluto and the Kuiper Belt<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"2\"><\/a>2<\/sup> Dust from a probable planetary collision:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wikipedia\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/2MASS_J08152329-3859234\">2MASS J08152329-3859234<\/a> (ASASSN-21qj)<\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/All_Sky_Automated_Survey_for_SuperNovae\">All Sky Automated Survey for SuperNovae<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Las_Cumbres_Observatory\">Las Cumbres Observatory<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/www.universiteitleiden.nl\/en\/news\/2023\/10\/dust-cloud-from-two-colliding-ice-planets-dims-light-of-parent-star\">Dust cloud from two colliding ice planets dims light of parent star<\/a>&#8220;<br>News, Universiteit Leiden\/Leiden University (October 11, 2023)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\">A planetary collision afterglow and transit of the resultant debris cloud<\/a>&#8220;<br>Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen, Eric Mamajek, Ludmila Carone, Franz-Josef Hambsch, Joseph Masiero, Amy Mainzer, J. Davy Kirkpatrick, Edward Gomez, Zo\u00eb Leinhardt, Jingyao Dou, Pavan Tanna, Arttu Sainio, Hamish Barker, St\u00e9phane Charbonnel, Olivier Garde, Pascal Le D\u00fb, Lionel Mulato, Thomas Petit, Michael Rizzo Smith (October 12, 2023) via arXiv<\/li>\n\n\n\n<li><a href=\"https:\/\/www.astronomy.ohio-state.edu\/asassn\/\">All-Sky Automated Survey for Supernovae<\/a><br>Ohio State University<\/li>\n\n\n\n<li><a href=\"https:\/\/lco.global\/\">LCO, Las Cumbres Observatory<\/a><br>(offices in Goleta, California)<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"3\"><\/a>3<\/sup> ASASSN-21q, also known as 2MASS J08152329-3859234; a quick look at star names and designations:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/twitter.com\/mattkenworthy\/status\/1475407205390340101?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1475407205390340101%7Ctwgr%5Ec7096ad333358d9f24986042ac597dfed1c735c2%7Ctwcon%5Es1_&amp;ref_url=https%3A%2F%2Fskyandtelescope.org%2Fastronomy-news%2Ftwo-worlds-have-ended-in-a-planetary-collision-and-a-new-one-has-begun%2F\">It seems that ASASSN-21qj is slowly rising back to normal&#8230;.<\/a>&#8220;<br>Matthew Kenworthy, Twitter\/X (December 27, 2021)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/science.nasa.gov\/get-involved\/citizen-science\/amateur-astronomers-help-discover-cosmic-crash\/\">Amateur Astronomers Help Discover Cosmic Crash<\/a>&#8220;<br>NASA Science Editorial Team, <a href=\"https:\/\/science.nasa.gov\/citizen-science\/\">Citizen Science<\/a>, Get Involved With NASA, NASA (December 8, 2023)<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/skyandtelescope.org\/astronomy-news\/two-worlds-have-ended-in-a-planetary-collision-and-a-new-one-has-begun\/\">Two Worlds Have Ended in a Planetary Collision \u2014 and a New One Has Begun<\/a>&#8220;<br>Monica Young, Sky and Telescope (October 12, 2023)<\/li>\n\n\n\n<li>A short (for me) look at how we&#8217;ve labeled stars\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/\">A Star by Any Other Name, and a Galilean Interlude<\/a>&#8221; (November 13, 2021)\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#one\">One Star, Many Names: Canicula, Mrgavyadha, BD-16\u00b01591\u2026<\/a>\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#old\">Old and New Names<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#designations\">Designations<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#gods\">Gods and Dogs<\/a>\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#patterns\">Patterns in the Sky<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#orion\">Orion&#8217;s Many Names<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#sirius\">Sirius: One of 9,999 Visible Stars<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/a-star-by-any-other-name-and-a-galilean-interlude\/#exceptional\">The Exceptional Few Stars With Names<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"4\"><\/a>4<\/sup> A distant star&#8217;s light, and Earth&#8217;s early days:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wikipedia\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Formation_and_evolution_of_the_Solar_System#Formation_of_the_planets\">Formation and evolution of the Solar System<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/History_of_Earth\">History of Earth<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Main_sequence\">Main sequence<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Protoplanetary_disk\">Protoplanetary disk<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Sun\">Sun<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/T_Tauri_star\">T Tauri star<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\">A planetary collision afterglow and transit of the resultant debris cloud<\/a>&#8220;<br>Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen, Eric Mamajek, Ludmila Carone, Franz-Josef Hambsch, Joseph Masiero, Amy Mainzer, J. Davy Kirkpatrick, Edward Gomez, Zo\u00eb Leinhardt, Jingyao Dou, Pavan Tanna, Arttu Sainio, Hamish Barker, St\u00e9phane Charbonnel, Olivier Garde, Pascal Le D\u00fb, Lionel Mulato, Thomas Petit, Michael Rizzo Smith (October 12, 2023) via arXiv<\/li>\n\n\n\n<li><a href=\"https:\/\/www.cosmos.esa.int\/web\/gaia\/dr3\">Gaia Data Release 3 (Gaia DR3)<\/a><br>Gaia, European Space Agency<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"5\"><\/a>5<\/sup> Distances and other details:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wikipedia\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/2MASS_J08152329-3859234\">2MASS J08152329-3859234<\/a> (ASASSN-21qj)<\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Asteroid_belt\">Asteroid belt<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Astronomical_unit\">Astronomical unit<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Giant-impact_hypothesis\">Giant impact hypothesis<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Habitable_zone\">Habitable zone<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Ice_giant\">Ice giant<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Mars\">Mars<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Uranus\">Uranus<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Neptune\">Neptune<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Solar_System\">Solar System<\/a><\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>A still-viable version of the giant impact hypothesis\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/\">Earth&#8217;s Moon: Heat, Stir \u2013 \u2013 \u2013<\/a>&#8221; (November 5, 2018)\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/#isotopes\">Isotopes and Disks<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/#filled\">A Filled Doughnut<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/#synestia\">Synestia?<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/#nebular\">Nebular Ideas<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/earths-moon-heat-stir\/#small\">A Small Sample: So Far<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"6\"><\/a>6<\/sup> Studying stars:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/arxiv.org\/pdf\/2310.08360.pdf\">A planetary collision afterglow and transit of the resultant debris cloud<\/a>&#8220;<br>Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen, Eric Mamajek, Ludmila Carone, Franz-Josef Hambsch, Joseph Masiero, Amy Mainzer, J. Davy Kirkpatrick, Edward Gomez, Zo\u00eb Leinhardt, Jingyao Dou, Pavan Tanna, Arttu Sainio, Hamish Barker, St\u00e9phane Charbonnel, Olivier Garde, Pascal Le D\u00fb, Lionel Mulato, Thomas Petit, Michael Rizzo Smith (October 12, 2023) via arXiv<\/li>\n\n\n\n<li><a href=\"https:\/\/www.cosmos.esa.int\/web\/gaia\/dr3\">Gaia Data Release 3 (Gaia DR3)<\/a><br>Gaia, European Space Agency<\/li>\n\n\n\n<li>&#8220;<a href=\"https:\/\/skyandtelescope.org\/astronomy-news\/two-worlds-have-ended-in-a-planetary-collision-and-a-new-one-has-begun\/\">Two Worlds Have Ended in a Planetary Collision \u2014 and a New One Has Begun<\/a>&#8220;<br>Monica Young, Sky and Telescope (October 12, 2023)<\/li>\n\n\n\n<li>Alien megastructure? Probably not, but still fascinating\n<ul class=\"wp-block-list\">\n<li>&#8220;<a href=\"https:\/\/brendans-island.com\/catholic-citizen\/kic-8462852-and-strange-stars\/\">KIC 8462852 and Strange Stars<\/a>&#8221; (December 2, 2016)\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/brendans-island.com\/catholic-citizen\/kic-8462852-and-strange-stars\/#tabby\">Tabby&#8217;s Star and Something Weird<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<p><sup><a name=\"7\"><\/a>7<\/sup> Odds and ends:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Wikipedia\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Argo_Navis\">Argo Navis<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/BD%2B20%C2%B0307\">BD+20\u00b0307<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/HD_12039\">HD 12039<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Astronomical_Union\">International Astronomical Union<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Johannes_Hevelius\">Johannes Hevelius<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Nicolas-Louis_de_Lacaille\">Nicolas-Louis de Lacaille<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Puppis\">Puppis<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Salt-Water_Poems_and_Ballads\">Salt-Water Poems and Ballads<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Sumer\">Sumer<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Zeta_Puppis\">Zeta Puppis<\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>They were looking for supernovae. What they found may become a double planet, like the Earth-Moon system, once it cools down. Or a planet with a giant moon, again like the Earth-Moon system. Then again, an oddly-uneven dusty disk may &hellip; <a href=\"https:\/\/brendans-island.com\/catholic-citizen\/colliding-planets-near-asassn-21qj-maybe\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"Scientists looking for supernovae noticed a very sunlike star that flared in infrared and then dimmed. It may be evidence of a planetary collision.","jetpack_seo_html_title":"Colliding Planets Near ASASSN-21qj: Maybe","jetpack_seo_noindex":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[192,4],"tags":[38,59,61,41,22,121,40,143],"class_list":["post-7687","post","type-post","status-publish","format-standard","hentry","category-journal","category-science-news","tag-astronomy","tag-cosmology","tag-exoplanets","tag-planets","tag-science","tag-solar-moons","tag-solar-planets","tag-stars"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p7Dwtw-1ZZ","jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/posts\/7687","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/comments?post=7687"}],"version-history":[{"count":4,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/posts\/7687\/revisions"}],"predecessor-version":[{"id":7692,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/posts\/7687\/revisions\/7692"}],"wp:attachment":[{"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/media?parent=7687"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/categories?post=7687"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/brendans-island.com\/catholic-citizen\/wp-json\/wp\/v2\/tags?post=7687"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}