Howdy Star Gazers and welcome to this episode
of Star Trails. I'm Drew and I'll be your guide
to the night sky for the week starting April
27th through May 3rd. This week a new moon promises
darker skies, the summer triangle points the
way to warmer days, and did you know stars sometimes
run away from home? More on that weird phenomenon
later. So grab a comfortable spot under the night
sky and let's get started. Before we dive into
this week's highlights, a quick update about
Comet C2025F2, also known as Comet Swan. Last
week we talked about this comet potentially putting
on a good show. Unfortunately, after the episode
aired, astronomers reported that Comet Swann
began to disintegrate as it approached the Sun.
This was likely due to the comet's first venture
into the inner solar system, where intense heat
and gravitational forces broke its nucleus apart.
Interestingly, a cloud of debris remained visible
shortly after the breakup, but of course that's
fading fast. With that, we say goodbye to Comet
Swan. As of now, I don't know of any other comets
expected to make a splash this year, but you
never know what might turn up. Keep in mind,
we didn't know Swan was out there until about
a month ago. Closer to home, tonight marks the
new moon, meaning our skies will be beautifully
dark and ideal for observing those fainter celestial
objects, such as galaxies and nebula. As the
week moves on, the moon will gradually brighten
into a delicate waxing crescent, reaching about
40 % illumination by the week's end. This crescent
will be visible shortly after sunset. Speaking
of bright sights, Venus reaches its greatest
illuminated extent this week, blazing in the
pre -dawn eastern sky. Venus will be exceptionally
bright, making it hard to miss if you're an early
riser. On the very next morning, April 28th,
Saturn joins Venus, creating a lovely close pairing
just under 4 degrees apart. Mars continues its
journey across the sky, now moving closer to
the famous Beehive Cluster, or M44. Binoculars
will show you Mars as it passes near this sparkling
open star cluster in the constellation Cancer.
Jupiter remains a prominent evening planet easy
to spot after sunset toward the western sky.
With a telescope, you'll easily spot its Galilean
moons dancing around it. For an added challenge,
look for a transit of one of the moons and see
if you can spot its shadow moving across Jupiter.
You can use an online tool such as Sky & Telescope's
Jupiter's Moons Calculator to determine when
events like this happen. I'll include a link
in the show notes. While the Lyrid meteor shower
peaked last week, keep an eye out, you might
still catch some lingering meteors streaking
across the sky, especially in the early part
of the week. Additionally, the Eta Aquarid meteor
shower is starting to ramp up, and although it
peaks next week, you might still see a few early
meteors during the pre -dawn hours, particularly
from darker locations. Now, shifting our gaze
to constellations, let's explore the emerging
summer triangle. This well -known trio of bright
stars, Vega, Deneb, and Altair, begins to rise
in the east around 10 pm, signaling the approach
of warmer months. Vega, in the small yet vibrant
constellation Lyra, is the brightest of the three,
and has been central to myths connected to music
and poetry. Lyra is home to the Ring Nebula.
M57, a beautiful planetary nebula visible as
a tiny smoke ring in small telescopes. Also noteworthy
is Epsilon Leary, famously known as the Double
Double, where careful observation reveals not
just one, but two pairs of stars orbiting closely
together. The constellation Cygnus the Swan is
marked by Deneb, one of the farthest bright stars
visible without optical aid. Within Cygnus, you'll
find the impressive North America Nebula, NGC
7000, named for its striking resemblance to our
continent, and the elegant Veil Nebula, the ghostly
remnants of a supernova explosion. Don't miss
Alberio at the Swan's Head, a double star pairing
with golden and blue hues. Have you ever heard
of a runaway star? These cosmic rebels have broken
free from their stellar neighborhoods and are
now barreling through the galaxy at astonishing
speeds. sometimes fast enough to escape the Milky
Way altogether. In simple terms, a runaway star
is a star moving significantly faster than the
stars around it, often hundreds of kilometers
per second. These stars don't just meander along
with the gentle galactic rotation like most of
their neighbors. They're hurtling through space
like they've got somewhere to be. Many are on
paths that suggest they've been violently ejected
from their original homes, flung out into the
galaxy by powerful forces. There are two main
mechanisms thought to be responsible for this
high -velocity behavior. One theory involves
supernova explosions in binary systems. In this
scenario two stars orbit one another in a binary
system. When the more massive star reaches the
end of its life and explodes in a supernova,
the sudden release of mass can destabilize the
system. The surviving star might be sent flying
off into space at tremendous speeds. The violence
of a supernova is enough to break the gravitational
bond and the energy imparted can slingshot the
remaining star into a lonely galactic journey.
Another theory points to gravitational interactions
in star clusters. In dense star clusters, particularly
those near the galactic center or in globular
clusters, three - or four -body interactions
can fling a star out at high velocity. This is
a bit like a cosmic game of pool. One star gets
knocked out of the cluster owing to complex gravitational
interactions with multiple other stars or a massive
black hole. One of the most exciting subsets
of runaway stars are hypervelocity stars. These
are moving so fast they're on escape trajectories
out of the galaxy entirely. These were first
predicted theoretically in the 1980s and confirmed
observationally in the 2000s. They often originate
from interactions with the supermassive black
hole at the center of the Milky Way. In a tight
dance between stars and the black hole's immense
gravity, one member of a binary pair can be captured
while the other is flung away at speeds exceeding
a million miles per hour. Among these standout
objects is HV2112, and I don't know if that's
a rush reference, but it would be appropriate.
2112 is a curious and controversial star located
in the small Magellanic cloud. While not technically
a hypervelocity star, it's earned attention for
its bizarre chemical makeup and potential status
as a thorn -zeitkau object, a theoretical hybrid
of a red supergiant and a neutron star. In terms
of observational characteristics, runaway stars
don't look all that different from other stars,
at least not through traditional telescopes.
They may appear as hot blue O or B -type stars,
large, young, and luminous. In other cases, they
might be older or redder stars. The key difference
is not what they look like, but how they move.
Their proper motion, that's their movement across
the sky relative to more distant stars, can be
measured over time with the help of space telescopes
and long -term sky surveys. Modern surveys like
Gaia have been instrumental in identifying runaway
stars. Gaia precisely measures the positions,
motions, and distances of more than a billion
stars in the Milky Way. By plotting the motion
vectors of these stars, astronomers can spot
the few that are zooming through the galaxy in
ways that don't conform to the general structure
and rotation of the Milky Way. As for backyard
astronomy, runaway stars aren't something we
normally seek out. They don't emit unique light
or have any distinguishing visual characteristics.
But some of the most famous runaway stars, like
Zeta Ophiuchae, are visible with amateur telescopes
or even binoculars. Zeta Ophiuchae is a massive
hot blue star that's plowing through space and
creating a visible bow shock. That's an arc -shaped
wave in the interstellar medium, much like a
boat cutting through water. Infrared images reveal
this shock wave in beautiful detail. So next
time you're under a clear sky, remember, somewhere
out there, maybe even above your head, a star
is fleeing a supernova. escaping a black hole,
or wandering alone from a starry birthplace it
no longer calls home. If you found this episode
helpful let me know and feel free to send in
your questions and observations. The easiest
way to do that is by visiting our website StarTrails
.Show. This is also a great way to share the
show with friends. Until next time, keep looking
up and exploring the night sky. Clear skies everyone!