Comet Halley is a prolific parent, matriarch responsible for the Eta-Aquarid meteors in May and October’s Orionid meteor shower. Every year between October 2 and November 7, Earth orbit encounters a elongated debris trail cast off by Halley – we know it as the Orionid meteor shower. This year Orionids peak the morning of October 21st.
Composite photo of Orionid meteors over Montana in 2018, via John Ashley.
Orionid abhors flamboyance, preferring to stay the course with 10 -20 exclamations an hour radiating from constellation Orion. Orionid makes up for paltry frequency with dizzying speed ( 66 kilometers per second ) and roughly half the meteors leaving characteristic ionized trails lingering for several seconds in night skies.
The Orionids radiate from a point near the upraised Club of the constellation Orion the Hunter. The bright star near the radiant point is Betelgeuse.
Constellation Orion is the radiant point, but meteors can appear over a wide angle view of dark skies. This year a waxing crescent moon delivers dark skies, ideal for Orionid watching. Best viewed between midnight and dawn.
Comet Halley doesn’t visit often ( 1910, 1986, again in 2061 ). Not to be forgotten, every October delivers the Orionid meteor shower – an annual event marked by Earth intersecting the orbit of Halley’s dust trail. Dust being tiny particles of ice and debris left in the wake as Halley hurtles through space. Dubbed “Orionids” because “shooting stars” streak from constellation Orion. This year the Orionids peak on October 20-21 in the northern hemisphere.
2014 is a good year for Orionid views – a cooperative waning crescent moon will rise just before dawn. Provided skies are clear, moonlight won’t compete with falling star twinkles. Orionids reliably deliver around 25 sightings an hour. Indulge just before dawn, far away from cities and light pollution.
Halley’s Comet last visited earth in 1986; far beyond the orbit of Uranus, it won’t be back until 2061. Halley laps the solar system approximately every 76 years – though light years away, it leaves behind a trail of cosmic dust. Twice a year our orbit passes this dust trail – in May the Aquarid meteors and in October the Orionids.
The Aquarids – named for their origin in the Aquarius constellation – peak tonight and tomorrow. The southern hemisphere has the best seats for this show with over 50 meteors an hour hitting the atmosphere at 66 Km/second. Northern hemisphere viewers can still see show, even though it’s hampered by Aquarius barely rising above the horizon.
Betelgeuse is a massive red giant star located in the Orion constellation. The three stars forming Orion’s belt make it one of the most distinguishable landmarks in the night sky. Find Orion’s belt, look up and slightly to the left; you are now pondering Betelgeuse, a dying star which could go “supernova” at any time. Betelgeuse is 640 light years from our planet, in cosmic terms just around the corner. Realistically far enough away to spare Earth when the inevitable happens.
A red giant is a star that has fused all its hydrogen supply, the core becomes compact and heats up enough to fuse helium into oxygen and carbon. The action of the core compacting is off set by an expansion of the outer regions which take on a red glow. Betelgeuse is huge; if you sat it on top of Earth it would cover an area all the way to Jupiter.
Science has no way to determine when Betelgeuse will run out of elements. The moment iron is produced it will collapse in a millisecond, splattering the universe with the building blocks to form new worlds. The universe has a circle of life, the seasons just happen to be millions of years long.