As Winter rapidly approaches and the Summer Milky Way sets below the horizon Dark Sky Wales Astronomer Martin Griffiths takes his monthly look at the night sky!
The nights are now well drawn in and the Autumn constellations dominate the sky high overhead whilst the great stars of summer fade away. Winter is fast on the heels of the autumn groups as Taurus, Gemini and Orion rise before midnight.
Moon in November:
New: 29th November
First quarter: 7th November
Full: 14th November
Last Quarter: 21st November
Planets in November:
Mercury: sets very soon after the sun as it lies in Scorpius in the middle of November after leaving superior conjunction at the end of October. Not brilliantly placed for observation this month
Venus: Continues to rise out of the evening dusk and brightens to magnitude -3.9. It does not set until 20:30 by mid month and is a glittering object in the southwest after sunset.
Mars: Moves to Capricorn by mid month and shines at a fairly bright 0.5 magnitude. It is still bright and immediately obvious as the brightest object in that part of the sky.
Jupiter: Continues to rise out of conjunction with the Sun and is a morning object in the constellation of Virgo shining at magnitude -1.6.
Saturn: Is in Ophiuchus and it in superior conjunction with the Sun by month’s end so not well placed for observation in November.
Uranus: Is just past opposition this month and shines as a tiny disk at magnitude 5.7 and is still at its best for this year.
Neptune: Is in Aquarius and is visible until 01:00 in the morning, and is still a dim object at magnitude 7.8.
Meteor showers in November.
There are two notable showers this month. The first is the Taurids which have their peak on the night of November 5/6th and is well placed for observation despite confusion with rockets and bonfires! This is an unpredictable shower associated with Comet Encke which has the shortest period of any comet at 3.3 years. There should be about 7 meteors per hours at its peak.
The second shower is the Leonids, associated with the comet Temple-Tuttle and they have their peak on the 17/18th November but are hampered by a waning gibbous moon. They have a usual rate of about 15 meteors per hour but the Leonids storm every 33 years, (last time in 1999) and the stream is a little unpredictable so watch out for this wonderful shower.
Interesting Events in November
On the 3rd November the waxing crescent moon joins Venus in the evening sky making a pleasing photo opportunity.
On the 14th November, the Moon is full and at its largest for this year and is the largest full moon or “supermoon” for the past 68 years at 33.5’ across. This is a good photo opportunity.
Constellation of the Month: Aries
The constellation of Aries is a collection of three fairly bright stars in an area of sky to the south and east of Andromeda. These three stars are surrounded by a large number of fainter constellation members within a border that seems far too big for the little constellation it contains. Aries was introduced by the Babylonians as the figure of a celestial “ram”. Other civilizations have imitated this and the Greeks thought of the group as the ram that carried Phryxis and Helle across the sky away from the angry goddess Ino. Unfortunately Helle did not hang on and fell into the sea and drowned, though the sea is now named after her – the Hellespont.
Aries contains very few objects of interest to the casual observer. There are few galaxies, but even for observers with large telescopes few deep sky delights to enthrall the astronomer in this barren and dismal constellation. Aries does contain some stars that are good targets for those interested in binary systems, but on the whole Aries is best skipped over if you are looking for something to really get your teeth into.
g Arietis is one of the nicest coloured doubles available to the amateur observer; sadly, it cannot be seen through a pair of binoculars. Nevertheless, it consists of two magnitude 4.5 stars that are well separated. The primary is a hot blue star of spectral type B, and its slightly fainter companion is an A type star that some observers have described as yellow, lilac or white. It is a famous star in that it was the first double star ever discovered, being found by Robert Hooke. Hooke was not a brilliant astronomer, but he was a good optics maker, and in fact was the inventor of the microscope. He found the star whilst observing a comet in 1664 and brought this celestial wonder to the attention of the recently formed Royal Society.
Another lovely coloured double star is 30 Arietis, a rather difficult object to detect visually in our light polluted times as the primary object shines at magnitude 6.2, and lies in a rather stark area of the sky. Both stars are dwarfs of spectral type F, but for some reason, the companion looks almost blue in colour compared to the yellow – white primary, probably some tricky optical effect causing this colour distinction.
Aries contains another faint star of interest to observers, and can be examined by those equipped solely with binoculars. This is the star 53 Arietis, a star with a very high proper motion that has been dubbed the “runaway” star. Examination of its motion has led astronomers to conclude that 53 Arietis has been ejected from the area of the Orion nebulae, M42, possibly as a result of a catastrophic supernova explosion. Two other high velocity stars can be traced back to this region, AE Auriga and Mu Columbae, causing each of these three stars seemingly to fly off along three points of the compass: west, north and south. What possibly may account for their motion is a matter of conjecture. All three stars are B type objects, obviously fairly young stars. If they were members of a system where the massive primary exploded, then the resultant mass loss by the detonating star could have resulted in the orbital “bonds” becoming broken, and the stars then being hurled away in different directions.
Just to the North of an Arietis is the 7th magnitude star HD 12661 at celestial coordinates RA 02h 04m 34s Dec +25 24m 51s, a G6V type yellow star similar to our Sun. In orbit around this body are two planets, the inner one has a mass 2.3 times that of Jupiter orbiting at 0.3 AU in 263 days, whilst the outer one has a mass of 1.5 times that of Jupiter and an orbital distance of 2.6 AU and a period of 1444 days. This is another system that could contain small planets such as Earth or Mars, but at the distance to HD 12661 of 105 LY, it is going to be difficult to observe them with current technology.
Another extrasolar system visible to the dedicated is that of HD 20367, shining at magnitude 6.4 and lying right on the border with Perseus. The star is marked on both The Sky and Sky Atlas 2000. This system contains a G0V type star with one attendant planet orbiting at 1.25 AU away from the parent star with a mass similar to that of Jupiter. This planet orbits HD 20367 in 500 days and is 95 LY distant. Both the aforementioned systems may make excellent targets for research or exploration once mankind has the technological ability to go to the stars.
Aries contains nothing further of interest to the modestly equipped amateur observer.