WEBVTT 00:00:07.470 --> 00:00:10.250 Howdy Star Gazers and welcome to this episode 00:00:10.250 --> 00:00:13.830 of Star Trails. I'm Drew and I'll be your guide 00:00:13.830 --> 00:00:16.370 to the night sky for the week starting April 00:00:16.370 --> 00:00:21.550 27th through May 3rd. This week a new moon promises 00:00:21.550 --> 00:00:24.890 darker skies, the summer triangle points the 00:00:24.890 --> 00:00:28.969 way to warmer days, and did you know stars sometimes 00:00:28.969 --> 00:00:32.439 run away from home? More on that weird phenomenon 00:00:32.439 --> 00:00:35.880 later. So grab a comfortable spot under the night 00:00:35.880 --> 00:00:41.060 sky and let's get started. Before we dive into 00:00:41.060 --> 00:00:44.100 this week's highlights, a quick update about 00:00:44.100 --> 00:00:50.820 Comet C2025F2, also known as Comet Swan. Last 00:00:50.820 --> 00:00:53.500 week we talked about this comet potentially putting 00:00:53.500 --> 00:00:57.049 on a good show. Unfortunately, after the episode 00:00:57.049 --> 00:01:00.570 aired, astronomers reported that Comet Swann 00:01:00.570 --> 00:01:03.469 began to disintegrate as it approached the Sun. 00:01:04.409 --> 00:01:07.510 This was likely due to the comet's first venture 00:01:07.510 --> 00:01:10.650 into the inner solar system, where intense heat 00:01:10.650 --> 00:01:14.349 and gravitational forces broke its nucleus apart. 00:01:15.569 --> 00:01:18.650 Interestingly, a cloud of debris remained visible 00:01:18.650 --> 00:01:21.930 shortly after the breakup, but of course that's 00:01:21.930 --> 00:01:25.989 fading fast. With that, we say goodbye to Comet 00:01:25.989 --> 00:01:30.010 Swan. As of now, I don't know of any other comets 00:01:30.010 --> 00:01:32.790 expected to make a splash this year, but you 00:01:32.790 --> 00:01:35.590 never know what might turn up. Keep in mind, 00:01:35.709 --> 00:01:38.329 we didn't know Swan was out there until about 00:01:38.329 --> 00:01:42.709 a month ago. Closer to home, tonight marks the 00:01:42.709 --> 00:01:45.849 new moon, meaning our skies will be beautifully 00:01:45.849 --> 00:01:49.590 dark and ideal for observing those fainter celestial 00:01:49.590 --> 00:01:53.310 objects, such as galaxies and nebula. As the 00:01:53.310 --> 00:01:56.069 week moves on, the moon will gradually brighten 00:01:56.069 --> 00:01:59.629 into a delicate waxing crescent, reaching about 00:01:59.629 --> 00:02:04.090 40 % illumination by the week's end. This crescent 00:02:04.090 --> 00:02:08.129 will be visible shortly after sunset. Speaking 00:02:08.129 --> 00:02:11.449 of bright sights, Venus reaches its greatest 00:02:11.449 --> 00:02:15.129 illuminated extent this week, blazing in the 00:02:15.129 --> 00:02:19.610 pre -dawn eastern sky. Venus will be exceptionally 00:02:19.610 --> 00:02:22.389 bright, making it hard to miss if you're an early 00:02:22.389 --> 00:02:26.310 riser. On the very next morning, April 28th, 00:02:26.330 --> 00:02:29.969 Saturn joins Venus, creating a lovely close pairing 00:02:29.969 --> 00:02:34.930 just under 4 degrees apart. Mars continues its 00:02:34.930 --> 00:02:38.009 journey across the sky, now moving closer to 00:02:38.009 --> 00:02:43.819 the famous Beehive Cluster, or M44. Binoculars 00:02:43.819 --> 00:02:47.219 will show you Mars as it passes near this sparkling 00:02:47.219 --> 00:02:52.000 open star cluster in the constellation Cancer. 00:02:52.639 --> 00:02:55.900 Jupiter remains a prominent evening planet easy 00:02:55.900 --> 00:02:58.939 to spot after sunset toward the western sky. 00:02:59.500 --> 00:03:02.639 With a telescope, you'll easily spot its Galilean 00:03:02.639 --> 00:03:06.319 moons dancing around it. For an added challenge, 00:03:06.419 --> 00:03:09.560 look for a transit of one of the moons and see 00:03:09.560 --> 00:03:12.500 if you can spot its shadow moving across Jupiter. 00:03:12.590 --> 00:03:17.250 You can use an online tool such as Sky & Telescope's 00:03:17.250 --> 00:03:20.729 Jupiter's Moons Calculator to determine when 00:03:20.729 --> 00:03:23.629 events like this happen. I'll include a link 00:03:23.629 --> 00:03:27.629 in the show notes. While the Lyrid meteor shower 00:03:27.629 --> 00:03:30.669 peaked last week, keep an eye out, you might 00:03:30.669 --> 00:03:33.490 still catch some lingering meteors streaking 00:03:33.490 --> 00:03:36.669 across the sky, especially in the early part 00:03:36.669 --> 00:03:40.569 of the week. Additionally, the Eta Aquarid meteor 00:03:40.569 --> 00:03:43.849 shower is starting to ramp up, and although it 00:03:43.849 --> 00:03:47.210 peaks next week, you might still see a few early 00:03:47.210 --> 00:03:50.370 meteors during the pre -dawn hours, particularly 00:03:50.370 --> 00:03:54.569 from darker locations. Now, shifting our gaze 00:03:54.569 --> 00:03:57.770 to constellations, let's explore the emerging 00:03:57.770 --> 00:04:01.620 summer triangle. This well -known trio of bright 00:04:01.620 --> 00:04:06.259 stars, Vega, Deneb, and Altair, begins to rise 00:04:06.259 --> 00:04:09.840 in the east around 10 pm, signaling the approach 00:04:09.840 --> 00:04:14.580 of warmer months. Vega, in the small yet vibrant 00:04:14.580 --> 00:04:18.040 constellation Lyra, is the brightest of the three, 00:04:18.220 --> 00:04:21.100 and has been central to myths connected to music 00:04:21.100 --> 00:04:25.379 and poetry. Lyra is home to the Ring Nebula. 00:04:25.529 --> 00:04:30.410 M57, a beautiful planetary nebula visible as 00:04:30.410 --> 00:04:35.949 a tiny smoke ring in small telescopes. Also noteworthy 00:04:35.949 --> 00:04:39.569 is Epsilon Leary, famously known as the Double 00:04:39.569 --> 00:04:42.930 Double, where careful observation reveals not 00:04:42.930 --> 00:04:46.810 just one, but two pairs of stars orbiting closely 00:04:46.810 --> 00:04:51.800 together. The constellation Cygnus the Swan is 00:04:51.800 --> 00:04:55.480 marked by Deneb, one of the farthest bright stars 00:04:55.480 --> 00:04:59.740 visible without optical aid. Within Cygnus, you'll 00:04:59.740 --> 00:05:03.720 find the impressive North America Nebula, NGC 00:05:03.720 --> 00:05:08.079 7000, named for its striking resemblance to our 00:05:08.079 --> 00:05:12.560 continent, and the elegant Veil Nebula, the ghostly 00:05:12.560 --> 00:05:16.550 remnants of a supernova explosion. Don't miss 00:05:16.550 --> 00:05:20.790 Alberio at the Swan's Head, a double star pairing 00:05:20.790 --> 00:05:31.629 with golden and blue hues. Have you ever heard 00:05:31.629 --> 00:05:36.389 of a runaway star? These cosmic rebels have broken 00:05:36.389 --> 00:05:39.350 free from their stellar neighborhoods and are 00:05:39.350 --> 00:05:42.269 now barreling through the galaxy at astonishing 00:05:42.269 --> 00:05:46.089 speeds. sometimes fast enough to escape the Milky 00:05:46.089 --> 00:05:50.610 Way altogether. In simple terms, a runaway star 00:05:50.610 --> 00:05:53.730 is a star moving significantly faster than the 00:05:53.730 --> 00:05:57.069 stars around it, often hundreds of kilometers 00:05:57.069 --> 00:06:01.050 per second. These stars don't just meander along 00:06:01.050 --> 00:06:04.410 with the gentle galactic rotation like most of 00:06:04.410 --> 00:06:06.990 their neighbors. They're hurtling through space 00:06:06.990 --> 00:06:10.449 like they've got somewhere to be. Many are on 00:06:10.449 --> 00:06:13.709 paths that suggest they've been violently ejected 00:06:13.709 --> 00:06:16.730 from their original homes, flung out into the 00:06:16.730 --> 00:06:20.670 galaxy by powerful forces. There are two main 00:06:20.670 --> 00:06:23.410 mechanisms thought to be responsible for this 00:06:23.410 --> 00:06:27.170 high -velocity behavior. One theory involves 00:06:27.170 --> 00:06:31.930 supernova explosions in binary systems. In this 00:06:31.930 --> 00:06:35.490 scenario two stars orbit one another in a binary 00:06:35.490 --> 00:06:38.740 system. When the more massive star reaches the 00:06:38.740 --> 00:06:41.879 end of its life and explodes in a supernova, 00:06:42.399 --> 00:06:45.519 the sudden release of mass can destabilize the 00:06:45.519 --> 00:06:49.360 system. The surviving star might be sent flying 00:06:49.360 --> 00:06:53.899 off into space at tremendous speeds. The violence 00:06:53.899 --> 00:06:56.680 of a supernova is enough to break the gravitational 00:06:56.680 --> 00:07:00.060 bond and the energy imparted can slingshot the 00:07:00.060 --> 00:07:03.220 remaining star into a lonely galactic journey. 00:07:03.850 --> 00:07:07.410 Another theory points to gravitational interactions 00:07:07.410 --> 00:07:11.649 in star clusters. In dense star clusters, particularly 00:07:11.649 --> 00:07:14.970 those near the galactic center or in globular 00:07:14.970 --> 00:07:18.470 clusters, three - or four -body interactions 00:07:18.470 --> 00:07:23.269 can fling a star out at high velocity. This is 00:07:23.269 --> 00:07:26.920 a bit like a cosmic game of pool. One star gets 00:07:26.920 --> 00:07:30.500 knocked out of the cluster owing to complex gravitational 00:07:30.500 --> 00:07:34.579 interactions with multiple other stars or a massive 00:07:34.579 --> 00:07:38.319 black hole. One of the most exciting subsets 00:07:38.319 --> 00:07:42.680 of runaway stars are hypervelocity stars. These 00:07:42.680 --> 00:07:46.259 are moving so fast they're on escape trajectories 00:07:46.259 --> 00:07:49.839 out of the galaxy entirely. These were first 00:07:49.839 --> 00:07:53.860 predicted theoretically in the 1980s and confirmed 00:07:53.860 --> 00:07:58.180 observationally in the 2000s. They often originate 00:07:58.180 --> 00:08:01.000 from interactions with the supermassive black 00:08:01.000 --> 00:08:04.480 hole at the center of the Milky Way. In a tight 00:08:04.480 --> 00:08:07.680 dance between stars and the black hole's immense 00:08:07.680 --> 00:08:11.480 gravity, one member of a binary pair can be captured 00:08:11.480 --> 00:08:14.439 while the other is flung away at speeds exceeding 00:08:14.439 --> 00:08:18.110 a million miles per hour. Among these standout 00:08:18.110 --> 00:08:23.029 objects is HV2112, and I don't know if that's 00:08:23.029 --> 00:08:25.689 a rush reference, but it would be appropriate. 00:08:26.629 --> 00:08:30.430 2112 is a curious and controversial star located 00:08:30.430 --> 00:08:34.539 in the small Magellanic cloud. While not technically 00:08:34.539 --> 00:08:37.779 a hypervelocity star, it's earned attention for 00:08:37.779 --> 00:08:41.139 its bizarre chemical makeup and potential status 00:08:41.139 --> 00:08:45.559 as a thorn -zeitkau object, a theoretical hybrid 00:08:45.559 --> 00:08:50.299 of a red supergiant and a neutron star. In terms 00:08:50.299 --> 00:08:53.759 of observational characteristics, runaway stars 00:08:53.759 --> 00:08:56.320 don't look all that different from other stars, 00:08:56.620 --> 00:08:59.200 at least not through traditional telescopes. 00:09:00.000 --> 00:09:04.259 They may appear as hot blue O or B -type stars, 00:09:04.759 --> 00:09:08.299 large, young, and luminous. In other cases, they 00:09:08.299 --> 00:09:12.220 might be older or redder stars. The key difference 00:09:12.220 --> 00:09:15.220 is not what they look like, but how they move. 00:09:15.639 --> 00:09:18.279 Their proper motion, that's their movement across 00:09:18.279 --> 00:09:21.840 the sky relative to more distant stars, can be 00:09:21.840 --> 00:09:24.679 measured over time with the help of space telescopes 00:09:24.679 --> 00:09:29.139 and long -term sky surveys. Modern surveys like 00:09:29.210 --> 00:09:32.909 Gaia have been instrumental in identifying runaway 00:09:32.909 --> 00:09:36.970 stars. Gaia precisely measures the positions, 00:09:37.190 --> 00:09:40.049 motions, and distances of more than a billion 00:09:40.049 --> 00:09:43.629 stars in the Milky Way. By plotting the motion 00:09:43.629 --> 00:09:46.669 vectors of these stars, astronomers can spot 00:09:46.669 --> 00:09:49.049 the few that are zooming through the galaxy in 00:09:49.049 --> 00:09:52.090 ways that don't conform to the general structure 00:09:52.090 --> 00:09:55.639 and rotation of the Milky Way. As for backyard 00:09:55.639 --> 00:09:58.639 astronomy, runaway stars aren't something we 00:09:58.639 --> 00:10:01.940 normally seek out. They don't emit unique light 00:10:01.940 --> 00:10:04.919 or have any distinguishing visual characteristics. 00:10:05.779 --> 00:10:08.620 But some of the most famous runaway stars, like 00:10:08.620 --> 00:10:12.460 Zeta Ophiuchae, are visible with amateur telescopes 00:10:12.460 --> 00:10:16.779 or even binoculars. Zeta Ophiuchae is a massive 00:10:16.779 --> 00:10:19.980 hot blue star that's plowing through space and 00:10:19.980 --> 00:10:23.720 creating a visible bow shock. That's an arc -shaped 00:10:23.720 --> 00:10:26.899 wave in the interstellar medium, much like a 00:10:26.899 --> 00:10:30.740 boat cutting through water. Infrared images reveal 00:10:30.740 --> 00:10:34.799 this shock wave in beautiful detail. So next 00:10:34.799 --> 00:10:37.740 time you're under a clear sky, remember, somewhere 00:10:37.740 --> 00:10:41.039 out there, maybe even above your head, a star 00:10:41.039 --> 00:10:44.620 is fleeing a supernova. escaping a black hole, 00:10:45.120 --> 00:10:48.460 or wandering alone from a starry birthplace it 00:10:48.460 --> 00:10:57.399 no longer calls home. If you found this episode 00:10:57.399 --> 00:11:00.080 helpful let me know and feel free to send in 00:11:00.080 --> 00:11:03.179 your questions and observations. The easiest 00:11:03.179 --> 00:11:07.000 way to do that is by visiting our website StarTrails 00:11:07.000 --> 00:11:10.240 .Show. This is also a great way to share the 00:11:10.240 --> 00:11:13.330 show with friends. Until next time, keep looking 00:11:13.330 --> 00:11:17.049 up and exploring the night sky. Clear skies everyone!