by Dick Cookman
Highlights: Comet Journal, Martian Landers, Meteor Showers, Celebrations, Planet Plotting, February Moon
Focus Constellations: Pisces, Andromeda, Aries, Perseus, Auria, Taurus, Orion, Gemini, Cancer, Leo, Lynx, Camelopardalis, Ursa Major, Draco, Ursa Minor, Cepheus, Cassiopeia
Comet C/2017 T2 PanSTARRS is a 9th magnitude comet moving from Perseus to Cassiopeia in February. On the 1st it is next to the Double Cluster, then slowly moves toward Cassiopeia during the month and may brighten to 8th magnitude. It is a long period comet which rose out of the Oort Cloud below the solar system on an orbit tilted at over 60 degrees to the solar system plane. It crossed the plane into northern skies in August and reached closest proximity to Earth on Dec. 29. Best viewing will be early in the evening when it is still high in the sky. Lunar glare will not compete with views of the comet during the week before and the week after New Moon. It will reach perihelion (closest to the Sun) on May 4, 2020, and then drop back through the plane of the solar system in September and embark on its long journey back to the Oort Cloud.
The Insight lander’s “mole” is digging again as it attempts to place the Heat Flow and Physics Properties Package (HP3) in position at a depth of 16 feet to accurately measure heat flow and seismic activity! After it became lodged at a very shallow depth and then popped out of the hole in October, initial success occurred on Nov. 21 when NASA announced that the probe had drilled another 1.25” when side pressure was applied with the robotic arm. On Dec. 16, the agency said that the mole was continuing to drill properly as it drilled another 2.5” deeper. After the holidays, Insight burrowed slowly until Jan. 21, when digging was interrupted as the “mole” backed out about 2 centimeters. The seismometer team has also determined the origin of the May 22 and July 25 marsquakes which were traced to an active fault zone in Cerberus Fossae. Since plate tectonics is not thought to exist on Mars, faulting may be produced by crustal temperature change.
The Curiosity rover is in Glen Torridon, the clay-bearing unit in the valley adjacent to Vera Rubin Ridge on 16,404 foot Mt. Sharp at the center of Gale Crater, the ancient remnant of a massive impact. On Sol 2607 (December 4, 2019), the western slope of Central Butte was in the rear view mirror and the rover was well on its way to Western Butte which was reached on December 9, 2019, (Sol 2609). Younger rocks comprising the Greenheugh pediment lie beyond and above Western Butte. The rocks of the pediment and butte are separated by an unconformity, a surface representing a period of time characterized by non-deposition or deposition and erosion. In either case, there is an interval of missing rock record which means that this area has no evidence to reveal the geologic history of that time period. After analyzing the rocks of Western Butte, Curiosity traveled toward the pediment and lost its attitude bearing on Sol 2650 (January 20, 2020). By Sol 2655, mission scientists succeeded in refreshing the position information and the rover resumed its journey. The Greenheugh pediment unconformity separates the mudstones of Glen Torridon from the overlying sandstone of the pediment which represents a totally different environment of deposition and a new chapter in Martian geologic evolution.
Meteor Showers, Asteroid Surprises
The Alpha Centaurid Meteor Shower is a Southern Hemisphere shower not visible in the northern hemisphere. February also hosts the Delta Leonids which is normally a rather minor shower.
February 8: Alpha Centaurids. Active Jan. 28-Feb. 21. Radiant 14h00m +59�. ZHR up to 25+, usually 5-6. 56 km/sec. Waxing Gibbous Moon. Progenitor: Unknown.
February 25: Delta Leonids. Active Feb. 15-Mar. 10. Radiant 11h12m +16�. ZHR 2. 23 km/sec. Waxing Crescent Moon. Progenitor: Asteroid 1987SY.
Four near-Earth asteroids passed by between Jan. 29 and Feb. 3. The largest was 10 meters in diameter and all were closer than the Moon.
February holidays include Groundhog Day (2nd), Valentine’s Day (14th), and Mardi Gras (25th). Each has religious and/or astronomical significance.
Groundhog Day is the American version of a Roman Catholic celebration, Candlemas, appropriated by the Church to replace the pagan recognition of the 1st cross-quarter day, half way between the winter solstice and spring equinox. “If Candlemas be fair and bright, Come, Winter, have another flight; if Candlemas bring clouds and rain, Go, Winter, and come not again.”
St. Valentine’s Day was a religious appropriation of a pagan fertility celebration adopted by the Romans as the fertility festival of Lupercalia. After a Roman priest named Valentine persisted in performing Christian marriages which had been declared illegal by anti-Christian Emperor Claudius, he was beaten, stoned, and beheaded on Feb. 14 in the third3rd Century. The Church later honored his martyrdom with Valentine’s Day. In 2020, even though the timing of Valentine’s Day isn’t defined by any astronomical event, Venus is glorious in the southwestern skies after sunset. The Goddess of Love shines down on the lovestruck, casting approval for the ancient pagan celebration and commemorating the life of the executed saint.
Mardi Gras celebrates the day before Ash Wednesday, when people over-indulge in preparation for the fast of Lent which ends with Easter. Astronomical events control timing of Mardi Gras since it is linked to Easter, which, in turn, is defined as the first Sunday following the full Moon closest to the spring equinox.
Mercury (-0.9 to +3.6) in Capricornus and Aquarius, Neptune (-7.9 to +8.0) in Aquarius, Venus (-4.0 to-4.1) in Aquarius and Pisces, and Uranus (+5.8) in Aries are evening planets in February. Mercury shines brightly near setting Capricorn in the southwestern sky after sunset in early February but dims rapidly in the latter half of the month after moving into Aquarius. At 9:00AM EST on the 10th, Mercury (-0.4) is at maximum Eastern Elongation (18�) then, after dimming to +0.6 magnitude, appears to pass within less than 6� of Neptune (+8.0) in Aquarius on the 15th. Mercury reaches Inferior Conjunction when it is between Earth and the Sun at 9:00PM EST on the 25th. Venus is significantly higher above the horizon. It rises higher and gets brighter each night in February as it approaches Inferior Conjunction in March when it will be closest to Earth.
Saturn (+0.6 to +0.7) and Jupiter (-1.7 to-1.8) in Sagittarius and Mars (+1.4 to +1.1) in Ophiuchus and Sagittarius are morning planets grouped together in the southeastern sky before sunrise. Mars rises about 4:00AM EST throughout the month and Jupiter follows less than an hour later. Saturn is the last arrival, rising a half hour before the Sun. Jupiter and Saturn are too close to the horizon to achieve the sharpest views in telescopes and Mars will get brighter and bigger as it approaches opposition in October when it is closest to Earth. At opposition it will appear over 60% larger and 2.5 times brighter.
The waning crescent Moon is 0.8� from Mars at 8:00AM EST on the 18th, 0.9� from Jupiter at 3:00PM EST on the 19th, and 1.7� from Saturn at 9:00AM EST on the 20th. The waxing crescent Moon passes 8.1� from Mercury at 8:00PM EST on the 23rd and 3.8� from Neptune at 2:00PM EST on the 24th. It is 6.0� from Venus at 7:00AM EST on the 27th and 4.0� from Uranus at 7:00AM EST on the 28th.
February’s New Moon on the 23rd at 10:32AM EST is the beginning of Lunation 1202 which ends 29.72 days later with the New Moon on March 24 at 5:28AM EST. The Full Moon of February on the 9th at 2:33PM EST is commonly known as the “Snow, Hunger, or Wolf” Moon. It was called the “Trapper’s Moon” in colonial times and in Medieval England it was the “Storm Moon.” Celts named it the “Moon of Ice” and the Chinese call it the “Budding Moon”. Anishinaabe (Odawa and Ojibwe) people recognize it as “Mkwa-giizis” (Bear Moon).
Lunar Perigee (minimum orbital distance) occurs on the 10th at 3:28PM EST when the Moon is at a distance of 223,980 miles (56.52 Earth radii). Apogee is on the 26th at 6:34AM EST when the Moon’s distance is 252,450 miles (63.70 Earth radii).