February 2017 – Skies News
02/1/2017
February Skies – by Dick Cookman
Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, February Moon
Focus Constellations: Leo, Cancer, Gemini, Orion, Taurus, Auriga, Perseus, Cassiopeia, Cepheus, Draco, Ursa Minor, Ursa Major, Lynx, Camelopardalis
Comet Journal
The short period (5.25 years) comet, 45P/Honda-Mrkos-Pajdusakova, is in the morning sky in February after passing through perihelion on Dec. 31st. As it moves from Aquila to Leo, it will be at 6th magnitude until mid-month after which it will decrease to 10th magnitude on the 28th.
Comet 2P Enke is in early evening skies in Pisces and is approaching 7th magnitude. It will brighten during February as it draws close to perihelion in early March.
Comet 41P/Tuttle-Giacobini-Kresak is between Leo and Cancer and Comet V2 Johnson is between Ursa Major and Lynx. They both may approach naked eye visibility in March and will be brightest in April/May and June/July respectively.
Mars Landers
Opportunity headed away from Marathon Valley and Spirit Mound toward an ancient fluid carved gully about one kilometer south of its location on the inside of the rim of the 14 mile wide Endeavor Crater in December. The challenging terrain, which includes slopes up to 20°, forced mission scientists to instruct the rover to occasionally backtrack and resume travel on slightly altered courses. Backing away from one of the difficult forays revealed an interesting surface disturbed by the wheels which invited analysis on Sol 4603 (Jan. 4, 2017). The Microscopic Imager, Alpha Particle X-ray Spectrometer, Panoramic Camera, and Navigation Camera were put to work to gather data after which the drive was resumed.
The valley that the rover is to investigate cuts through the rim of the crater and is about 600 feet long. It may have been carved by water or by a debris flow composed of water and rubble. In addition to investigating the origin of the valley, Opportunity will look for differences between the rocks on the floor of the crater and the sulfate-rich rocks outside the crater. Water flows downhill into the crater and the environment deep within Endeavor may have differed from that outside in chemistry or timing.
Between Sol 4580 (Dec. 11, 2016) and Sol 4623 (Jan. 24, 2017), the rover progressed to the southwest covering almost 750 feet (225+ meters). The rover is driving on slopes tilted away from the Sun so power is constrained and the drives are limited in distance. Some sols following the drives have been “recharge” sols, sols with limited rover activity.
Solar array energy production averaged from 416 to 520 watt-hours. Total odometry is 27.26 miles (43.87 kilometers).
Curiosity is ascending the flank of Mt. Sharp, Gale Crater’s central peak and studying the Murray Formation rock layers. As the rover moves upward it is encountering progressively younger layers which reveal the changing environment conditions which existed when they were formed. The mudstone rock layers which were formed in an aqueous (lake?) environment are comprised primarily of clay minerals with silt and sand as minor components. The lower, older layers were dark colored due to their magnetite content. Magnetite is a form of iron oxide formed in low oxygen environments.
As Curiosity climbed higher, the rock layers assumed a redder color reflecting the transition from magnetite to hematite which was formed in an oxygen abundant (possibly nearshore) environment. Siltstone and sandstone layers became more abundant possibly due to more active conditions such as a nearer shore setting where waves removed the finer grained clays. Cross bedded layers caused by moving currents and 3 billion year old layers with mudcracks suggest nearshore or onshore conditions where the sediment may have been subjected to drying and cracking due to evaporation of the shallow water. Calcium sulfate mineral veins found in the the underlying mudstones and in the mudcracked rocks suggest that cracking of the rock due to weight of overlying material was followed by mineralization by ground water flowing through the cracks and interstices. The mineralized veins also contain boron, an evaporite constituent made famous by the mule teams which hauled borax out of Death Valley.
Meteor Showers
Meteors in the northern hemisphere are few and far between in February as the Alpha Centaurid Shower which peaks on the 8th and typically produces 25+ meteors per hour is confined to the southern hemisphere. The Delta Leonid Shower in our eastern evening skies on the 24th is a very weak shower unlikely to draw much attention.
Planet Plotting
February morning planets include Mercury (-0.3 to -1.1), Saturn (+0.5), and Jupiter (-2.1 to -2.3). Mercury was highest in the eastern sky on Jan. 21st when it was at maximum elongation west of the Sun. In February it will be low in the southeast before sunrise and will gradually descend and disappear into the glow of sunrise as it moves out of Sagittarius, through Capricornus, and into Aquarius by month’s end. Saturn rises about 4 hours before the Sun in Ophiuchus and is in the southern sky before sunrise. Jupiter (-2.1 to -2.3) is in Virgo and rises before midnight. It sets after sunrise. It is gradually getting brighter as it approaches opposition in April.
Venus (-4.6 to -4.7) and Mars (+1.1 to +1.3) are evening planets which will be separated by 5.4° in Pisces on February 2nd. Venus will appear 11.5° from Uranus (+5.8 to +5.9) on the 27th. Neptune (+7.9) is in Aquarius.
Planet Constellation Magnitude Planet Passages
Sun..Capricornus, Aquarius…-26.8………….New Moon, 2/26 …………………………………………………………………9:59PM EST Mercury..Sagittarius, Capricornus, Aquarius…..-0.3 to -1.1
Venus…..Pisces…-4.6 to 4.7………..Mars, 5.4°E, 2/2, 6PM EST Venus……………………………..Uranus, 11.5°ESE, 2/27, 7PM EST
Mars…….Pisces…+1.1 to +1.3…..Venus, 5.4°W, 2/2, 6PM EST ………………………………………Uranus, 0.57°SSE, 2/26, 7PM EST Jupiter ………Virgo…………..-2.1 to -2.3 Saturn…….Ophiuchus……..+0.5
Uranus..Pisces…+5.8 to +5.9..Mars, 0.57°SSE, 2/26, 7PM EST
…………………………………….Venus, 11.5°WNW, 2/27, 7PM EST
Neptune…..Aquarius……….+7.9
February Moon
The New Moon of February 26th at 9:59AM EST is the beginning of Lunation 1165 which ends 29.92 days later with the New Moon of March 27th at 9:58PM EST. An annular eclipse of the Sun occurs in conjunction with the February New Moon. It culminates at 9:54 AM EST and will be visible in southern South America in the morning and western South Africa at sunset.
The Full Moon in February in Leo occurs at 7:33AM EST on the 10th. A penumbral eclipse of the Moon will occur for western Asia, Europe, and maritime eastern North America. The February Moon is called the “Snow, Hunger, or Wolf Moon”. Colonial Americans named it the “Trapper’s Moon”. To the Celts it was the “Ice Moon”, and the Chinese refer to it as the “Budding Moon”. Medieval English thought of it as the “Storm Moon”, and the Anishinaabe (Odawa and Ojibwe) people of northern Michigan recognize it as “Namebini-giizis” (Suckerfish Moon).
Lunar perigee (closest to Earth) is 229,143 miles or 57.82 Earth radii on the 6th at 9:15AM EST. Apogee position in orbit (maximum orbital distance) is at 251,257 miles (63.40 Earth radii) from Earth on the 18th at 4:00PM EST.
Cecil Adams’ reasons why we need the Moon:
Reason #4: “It creates tides. The moon’s orbit used to be a lot closer to earth, thus generating much stronger, higher tides. These tides left extensive tidal pools, where the ocean’s primordial soup of amino acids and other organic compounds could be concentrated via repeated evaporation. Synchronization between tidal flow and exposure to solar UV radiation may have resulted in the petri dish necessary for life to evolve. Tides were helpful too in the transition of life onto land, depositing small organisms and biomass into semiaquatic marshlike environments. Evidence for this is found in 3.5 billion year old stromatolites—stratified rock formed by ancient bacterial action—whose layers show the Moon’s influence on the earth’s spin rate and tides throughout the early development of life.”
Explanation: The height of modern stromatolites found in tidal flats off Australia is related to tidal heights. Ancient (billion+ year old) stromatolites are much taller, attesting to higher tides associated with a nearby Moon. Additional evidence includes 400 million year old Paleozoic coral fossils which display 400 daily growth rings per annual section. In contrast, modern corals have 365 daily growth rings per annual section indicating a slowing of rotation of the Earth. The resulting angular momentum lost from the Earth is transferred to the Moon, forcing it to retreat in order to conserve angular momentum for the Earth — Moon system. Current measurements of changes in lunar distance and Earth rotation rates are consistent with the fossil evidence. Scientists expect lunar retreat and slowing of Earth’s rotation to continue until the length of the day is synchronous with the length of the month and the Moon is tidally locked above a single location on Earth. Who will own the Moon in that distant era?
Planet Constellation Magnitude Moon Passage ……………………………………………………………Moon Phase/Age
Sun………Aquarius…………-26.8…………9:59PM EST, 2/26 ……………………………………………………………New ~ 0 days Mercury….Aquarius………….-1.1…….2.4°NNW, 8PM EST, 2/25 …………………………………………..Waning Crescent ~29.04 days Venus……Pisces……………..-4.6……35°ESE, 0:01AM EST, 2/1 …………………………………………..Waxing Crescent ~4.02 days Mars………Pisces…………..+1.3………30°ESE, 0:01AM EST, 2/1 …………………………………………..Waxing Crescent ~4.02 days Jupiter……..Virgo…………..-2.2…….2.6°NNE, Noon EST, 2/15 …………………………………………..Waning Gibbous ~18.70 days Saturn…….Ophiuchus………+0.5………3.6°N, 7PM EST, 2/20 …………………………………………Waning Crescent ~ 24.00 days Uranus…….Pisces……………+5.8……….3.3°SSE, 5AM EST, 2/2 …………………………………………..Waxing Crescent ~6.08 days Neptune……Aquarius……….+7.9……0.14°NNE, 4PM EST, 2/26 …………………………………………..Waning Crescent ~29.87 days