A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL
Our hothouse planet of the solar system, Venus, is possibly a product of how close it is to the Sun, new research reveals. The team who have come up with a definition of a “Venus zone” around stars, saying that knowing where this area is could help pin down other areas that are more habitable for potential life.
“We believe the Earth and Venus had similar starts in terms of their atmospheric evolution,” stated lead author Stephen Kane, an astronomer at San Francisco State University. “Something changed at one point, and the obvious difference between the two is proximity to the Sun.”
The habitable region around a star is poorly understood because scientists don’t quite know what conditions are necessary for life. It usually refers to the area where liquid water is possible, although this also depends on the climate of the planet itself. Clouds, terrain and atmospheric composition are just some of the variables that could affect habitability.
Artist’s impression of a massive asteroid belt in orbit around a star. Credit: NASA-JPL / Caltech / T. Pyle (SSC)
To better figure out where potential Venus-like exoplanets lurk, Kane’s team used data from the planet-hunting Kepler Space Telescope and examined solar flux — or how much solar energy a planet gets — to figure out where the Venus zone would be. The zone is then defined between two regions: where a planet could have the “runaway greenhouse effect” seen on Venus, and the spot where the planet is so close to its star that energy would wear away its atmosphere.
The first step would be pinpointing which planets reside within these zones. In future decades, astronomers could then examine the planetary atmospheres with telescopes to learn more about how they are composed — and how similar they are to Earth or Venus. Meanwhile, Kane’s team plans to model if carbon in the planet’s atmosphere could affect the boundaries of the zone.
“If we find all of these planets in the Venus Zone have a runaway greenhouse-gas effect, then we know that the distance a planet is from its star is a major determining factor,” Kane stated. “That’s helpful to understanding the history between Venus and Earth.”
A preprint version of the paper is available on the Arxiv website. The research has been accepted for publication in Astrophysical Journal Letters.
The above sequence depicts a rare supernova explosion. The topic panel
Massive stars end their lives dramatically. Once the nuclear fuel deep within their cores is spent, there’s no longer any outward pressure to push against gravity, and the star collapses. But while the inner layers fall in to form a black hole or a neutron star, the outer layers fall faster, hitting the inner layers, and rebounding in a huge supernova explosion.
That’s the textbook definition. But some of these supernovae defy explanation. In 2011 one such explosion, dubbed SN 2011dh, pierced the Whirlpool galaxy, roughly 24 million-light years away. At the time astronomers were baffled. But now, thanks to NASA’s Hubble Space Telescope, they’ve discovered a companion star to this rare supernova and fit the final puzzle pieces together.
SN 2011dh is a Type IIb supernova, unusual in that it contains very little hydrogen and unexplainable via a textbook definition. Even so, astronomers can shed light on the progenitor star simply by digging through archived images from HST. Thanks to HST’s wealth of data and the fact that it observes the Whirlpool galaxy often, two independent research teams both detected a source — a yellow supergiant star — at the right location.
But astronomers don’t think yellow supergiant stars are capable of becoming supernovae … at least not in isolation.
At this point, controversy arose within the astronomical community. Several experts proposed that the observation was a false cosmic alignment and that the actual progenitor was an unseen massive star. Other experts proposed that the progenitor could have been the yellow supergiant, but that it must have belonged in a binary star system.
When a massive star in a binary system overflows its Roche lobe — the region outside that star where gravity dominates — it can pour material onto its smaller companion, therefore losing its hydrogen envelope and shrinking in mass.
At the time the mass-donor explodes, the companion star should be a massive blue star, having gained material during the mass transfer. Its high temperature should also cause it to emit mostly in the ultraviolet range, therefore rendering it invisible in any visible images.
So Gastón Folatelli from the Kavli Institute for the Physics and Mathematics of the Universe (IPMU) and colleagues decided to take a second look at the mysterious supernova in ultraviolet light. And their observations matched their expectations. The original supernova had faded, and a different point source had taken its place.
“One of the most exciting moments in my career as an astronomer was when I displayed the newly arrived HST images and saw the object right there, where we had anticipated it to be all along,” said Folatelli in a news release.
The research illustrates the intricate interplay between theory and observation. Astronomers often rely on theories long before they gain the technology necessary to provide the correct observations or spend years trying to explain odd observations with complex theoretical modeling. More often, however, the two coexist as theory and observation banter back and forth.
The findings have been published in the Astrophysical Journal Letters and are available online.
A solar blast erupts in this picture captured by the Solar and Heliospheric Observatory on Sept. 10, 2014. Credit: ESA / NASA / SOHO
Bim, bam, smash! The Sun hurled two clouds of particles in our general direction, putting space weather watchers on alert. There’s now a high chance of auroras on Sept. 12 (Friday), according to the National Oceanic and Atmospheric Administration, with more activity possible during the weekend.
The coronal mass ejections erupted Sept. 9 and Sept. 10 from sunspot AR2158. The Sept. 10 flare packed the strongest class punch the sun has, an X-flare, which briefly caused HF radio blackouts on Earth. We have some amateur shots of the sunspot and Sun below.
“Radio emissions from shock waves at the leading edge of the CME suggest that the cloud tore through the sun’s atmosphere at speeds as high as 3,750 km/s [2,330 miles per second],” wrote SpaceWeather.com. “That would make this a very fast moving storm, and likely to reach Earth before the weekend. Auroras are definitely in the offing.”
Photographer John Chumack captured the Sun and AR2158 in these pictures from Monday (Sept. 8). If you’ve got some great Sun shots to share, be sure to put it on our Universe Today Flickr group!
Sunspot AR2158 taken on Sept. 8, 2014. Credit: John ChumackThe Sun on Sept. 8, 2014, including active sunspots. Credit: John Chumack
The Expedition 40 crew returns to Earth, as seen from the International Space Station Sept. 10, 2014. Credit: Reid Wiseman / Twitter
Wow! See that bright streak in the photo above? That’s a shot of the Expedition 40 crew making a flawless return from the International Space Station yesterday (Sept. 10) … a shot taken from space itself.
“Our view of the picture perfect reentry of TMA-12M,” wrote Expedition 41 astronaut Reid Wiseman, who just hours before bid farewell to Steve Swanson (NASA), Alexander Skvortsov (Roscosmos) and Oleg Artemyev (Roscosmos). The re-entry was in fact so perfect that TV cameras caught the parachute immediately after deployment, which doesn’t always happen.
As you can see in the video replay below, the Soyuz made a bulls-eye landing near Dzhezkazgan, Kazakhstan at 10:23 p.m. EDT (2:23 a.m. UTC). There are now only three people tending to the space station until the rest of the Expedition 41 crew launches, which is expected to happen Sept. 25.
An image of globular cluster M54 taken by the Very Large Telescope Survey Telescope at the European Southern Observatory's Paranal Observatory in northern Chile. Credit: ESO
This new picture of M54 — a part of a satellite galaxy to the Milky Way called the Sagittarius Dwarf Galaxy — is part of a “test case” astronomers have to figure out a mystery of missing lithium.
For decades, astronomers have been aware of a dearth of lithium in our own galaxy, the Milky Way. This image from the Very Large Telescope’s Survey Telescope represents the first effort to probe for the element outside of our galaxy.
“Most of the light chemical element lithium now present in the Universe was produced during the Big Bang, along with hydrogen and helium, but in much smaller quantities,” the European Southern Observatory stated.
“Astronomers can calculate quite accurately how much lithium they expect to find in the early Universe, and from this work out how much they should see in old stars. But the numbers don’t match — there is about three times less lithium in stars than expected. This mystery remains, despite several decades of work.”
In any case, observations of M54 show that the amount of lithium there is similar to the Milky Way — meaning that the lithium problem is not confined to our own galaxy. A paper based on the research was published in the Monthly Notices of the Royal Astronomical Society. The research was led by Alessio Mucciarelli at the University of Bologna in Italy.
Image of Rosetta's solar array and comet 67P/C-G taken by Philae on Sept. 7, 2014 (ESA/Rosetta/Philae/CIVA)
Spacecraft “selfies” are always a treat and this one is doubly awesome: taken by the Philae lander piggybacked onto ESA’s Rosetta, it shows one of the spacecraft’s 14-meter-long (46-foot) solar arrays glinting with reflected sunlight while off in the distance is the double-lobed nucleus of Comet 67P/Churyumov-Gerasimenko!
Rosetta has been circling the comet for over a month now and returning some truly amazing images, but leave it to little Philae to put it all into perspective. Such a show-stealer! (Not that we mind, of course.)
The image above was acquired with Philae’s CIVA (Comet nucleus Infrared and Visible Analyzer) instrument on Sept. 7, 2014, from a distance of 50 km (31 miles) from Comet 67P/C-G. It’s actually a composite of two separate images made with different exposures adjusted for the lighting disparities between the spacecraft and comet.
Artist impression of Philae on the surface of comet 67P/Churyumov-Gerasimenko. Credit: ESA/ATG medialab
The Philae (say “FEE-lay”) lander itself weighs 100 kg (220 lbs) and is about a meter wide and 80 cm high (3.2 x 2.6 feet). The CIVA instrument, one of ten installed on the lander, is composed of seven miniature cameras that will take panoramic pictures of 67P’s surface and reconstruct its structure in 3D, as well as a microscope and a near-infrared imager to study its composition, texture, and reflectivity. (Source)
This is the second image from Philae this year to feature part of the Rosetta spacecraft (but the first to show the comet); the previous was taken in April 2014.
Back in 2007 Philae took a shot that showed Rosetta’s solar panel and Mars; check that one out here.
Currently Rosetta is being transitioned to its Global Mapping Phase (GMP). This is an incredibly intensive process that will determine how close the spacecraft will be able to get to the surface of the comet as engineers search for the best landing area to which to deploy Philae in November.
Learn more about the Rosetta mission and Comet 67P/C-G here.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.
NASA’s first completed Orion crew module sits atop its service module at the Neil Armstrong Operations and Checkout Facility at Kennedy Space Center in Florida in early September 2014. The crew and service module will be transferred soon to another facility for fueling. Credit: NASA/Rad Sinyak
This past weekend technicians completed assembly of NASA’s first Orion crew module at the agency’s Neil Armstrong Operations and Checkout (O & C) Facility at the Kennedy Space Center (KSC) in Florida, signifying a major milestone in the vehicles transition from fabrication to full scale launch operations.
The black Orion crew module (CM) sits stacked atop the white service module (SM) in the O & C high bay photos, shown above and below.
The black area is comprised of the thermal insulating back shell tiles. The back shell and heat shield protect the capsule from the scorching heat of re-entry into the Earth’s atmosphere at excruciating temperatures reaching over 4000 degrees Fahrenheit (2200 C) – detailed in my story here.
Technicians and engineers from prime contractor Lockheed Martin subsequently covered the crew module with protective foil. The CM/SM stack was then lifted and moved for the installation of the Orion-to-stage adapter ring that will mate them to the booster rocket.
Lifting and stacking NASA’s first completed Orion crew and service modules at the Neil Armstrong Operations and Checkout Facility at Kennedy Space Center in Florida in early September 2014. Credit: NASA/Rad Sinyak
At the conclusion of the EFT-1 flight, the detached Orion capsule plunges back and hits the Earth’s atmosphere at 20,000 MPH (32,000 kilometers per hour).
“That’s about 80% of the reentry speed experienced by the Apollo capsule after returning from the Apollo moon landing missions,” Scott Wilson, NASA’s Orion Manager of Production Operations at KSC, told me during an interview at KSC.
The next step in Orion’s multi stage journey to the launch pad follows later this week with transport of the CM/SM stack to another KSC facility named the Payload Hazardous Servicing Facility (PHFS) for fueling, before moving again for the installation of the launch abort system (LAS) in yet another KSC facility.
Stacking NASA’s first completed Orion crew and service modules at the Neil Armstrong Operations and Checkout Facility at Kennedy Space Center in Florida in early September 2014. Credit: NASA/Rad Sinyak
The Orion EFT-1 test flight is slated to soar to space atop the mammoth, triple barreled United Launch Alliance (ULA) Delta IV Heavy rocket from Cape Canaveral, Florida, on Dec. 4, 2014 .
The state-of-the-art Orion spacecraft will carry America’s astronauts on voyages venturing farther into deep space than ever before – past the Moon to Asteroids, Mars and Beyond!
NASA’s first completed Orion crew and service modules being moved inside the High Bay at the Neil Armstrong Operations and Checkout Facility at Kennedy Space Center in Florida in early September 2014. Credit: NASA/Rad Sinyak
NASA is simultaneously developing a monster heavy lift rocket known as the Space Launch System or SLS, that will eventually launch Orion on its deep space missions.
The maiden SLS/Orion launch on the Exploration Mission-1 (EM-1) unmanned test flight is now scheduled for no later than November 2018 – read my story here.
SLS will be the world’s most powerful rocket ever built.
The two-orbit, four and a half hour EFT-1 flight will lift the Orion spacecraft and its attached second stage to an orbital altitude of 3,600 miles, about 15 times higher than the International Space Station (ISS) – and farther than any human spacecraft has journeyed in 40 years.
Orion service module assembly in the Operations and Checkout facility at Kennedy Space Center – now renamed in honor of Neil Armstrong. Credit: Ken Kremer/kenkremer.com
The EFT-1 mission will test the systems critical for EM-1 and future human missions to deep space that follow.
The Orion EFT-1 capsule has come a long way over the past two years of assembly.
The bare bones, welded shell structure of the Orion crew cabin arrived at KSC in Florida from NASA’s Michoud facility in New Orleans in June 2012 and was officially unveiled at a KSC welcoming ceremony on 2 July 2012, attended by this author.
“Everyone is very excited to be working on the Orion. We have a lot of work to do. It’s a marathon not a sprint to build and test the vehicle,” said Jules Schneider, Orion Project manager for Lockheed Martin at KSC, during an exclusive 2012 interview with Universe Today inside the Orion clean room at KSC.
Orion crew capsule, Service Module and 6 ton Launch Abort System (LAS) mock up stack inside the transfer aisle of the Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC) in Florida. Service module at bottom. Credit: Ken Kremer/kenkremer.com
Stay tuned here for Ken’s continuing Orion, SLS, Boeing, Sierra Nevada, Orbital Sciences, SpaceX, commercial space, Curiosity, Mars rover, MAVEN, MOM and more Earth and planetary science and human spaceflight news.
Orion crew module back shell tiles and panels inside the Neil Armstrong Operations and Checkout Building high bay at the Kennedy Space Center in Florida. Credit: Ken Kremer – kenkremer.comOrion EFT-1 capsule under construction inside the Structural Assembly Jig at the Operations and Checkout Building (O & C) at the Kennedy Space Center (KSC); Jules Schneider, Orion Project Manager for Lockheed Martin and Ken Kremer, Universe Today. Credit: Ken Kremer – kenkremer.com
A map of Saturn's F ring from 2006 shows one of the few bright, extended clumps (indicated by a green box) seen during six years of observation by Cassini. Image credit: NASA/JPL-Caltech/SSI
Nothing stands still. Everything evolves. So why shouldn’t Saturn’s kookie, clumpy F ring put on a new face from time to time?
A recent NASA-funded study compared the F ring’s appearance in six years of observations by the Cassini mission to its appearance during the Saturn flybys of NASA’s Voyager mission, 30 years earlier.
A kink in part of Saturn’s F ring. While the ring is held together by the shepherd moons Prometheus and Pandora, which orbit just inside and outside the ring, embedded moonlets are believed responsible for the kinks and clumps. The rings is several hundred kilometers wide. Credit: NASA
While the F ring has always displayed clumps of icy matter, the study team found that the number of bright clumps has nose-dived since the Voyager space probes saw them routinely during their brief flybys 30 years ago. Cassini spied only two of the features during a six-year period.
Scientists have long suspected that moonlets up to 3 miles (5 km) wide hiding in the F ring are responsible for its uneven texture. Kinks and knots appear and disappear within months compared to the years of observation needed changes in many of the other rings.
Saturn’s F ring is extremely narrow compared to the historic A, B and C rings. It measures just a few hundred kilometers across. Credit: NASA/Cassini
“Saturn’s F ring looks fundamentally different from the time of Voyager to the Cassini era,” said Robert French of the SETI Institute in Mountain View, California, who led the study along with SETI Principal Investigator Mark Showalter. “It makes for an irresistible mystery for us to investigate.”
A 2007 artist impression of small boulder-like chunks of ice that comprise Saturn’s rings. The largest are about 10-12 feet across.They clump together to form elongated, curved aggregates, continually forming and dispersing. Credit: NASA/JPL/Univ. of Colorado
Because the moonlets lie close to the ring and cross through it every orbit, the research team hypothesizes that the clumps are created when they crash into and pulverize smaller ring particles during each pass. They suspect that the decline in the number of exceptionally bright kinks and the clumps echoes a decline in the number of moonlets available to do the job.
So what happened between Voyager and Cassini? Blame it on Prometheus. The F ring circles Saturn at a delicate point called the Roche Limit. Any moons orbiting closer than the limit would be torn apart by Saturn’s gravitational force.
The culprit? Prometheus measures 74 miles (119 km) across and orbits the inner edge of Saturn’s F ring. Credit: NASA
“Material at this distance from Saturn can’t decide whether it wants to remain as a ring or coalesce to form a moon,” said French. “Prometheus orbits just inside the F ring, and adds to the pandemonium by stirring up the ring particles, sometimes leading to the creation of moonlets, and sometimes leading to their destruction.”
Every 17 years the orbit of Prometheus aligns with the orbit of the F ring in a way that enhances its gravitational influence. The researchers think the alignment spurs the creation of lots of extra moonlets which then go crashing into the ring, creating bright clumps of material as they smash themselves to bits against other ring material.
Sounds like a terrifying version of carnival bumper cars. In this scenario, the number of moonlets would gradually drop off until another favorable Prometheus alignment.
The Voyagers encounters with Saturn occurred a few years after the 1975 alignment between Prometheus and the F ring, and Cassini was present for the 2009 alignment. Assuming Prometheus has been “working” to build new moons since 2009, we should see the F ring light up once again with bright clumps in the next couple years.
As the Chinese proverb says, “May you live in interesting times,” and while the promise of Comet ISON dazzling observers didn’t exactly pan out as hoped for in early 2014, we now have a bevy of binocular comets set to grace evening skies for northern hemisphere observers. Comet 2012 K1 PanSTARRS has put on a fine show, and comet C/2014 E2 Jacques has emerged from behind the Sun and its close 0.085 AU passage near Venus and has already proven to be a fine target for astro-imagers. And we’ve got another icy visitor to the inner solar system beating tracks northward in the form of Comet C/2013 V5 Oukaimeden, and a grand cometary finale as comet A1 Siding Spring brushes past the planet Mars. That is, IF a spectacular naked eye comet doesn’t come by and steal the show, as happens every decade or so…
Comet E2 Jacques crossing Cassiopeia as seen from the island of Malta. Credit: Leonard Mercer.
Anyhow, here’s a rapid fire run down on what you can expect from three of these binocular comets that continue to grace the twilight skies this Fall.
(Note that mentions of comets “passing near” a given object denote conjunctions of less than an angular degree of arc unless otherwise stated).
C/2014 E2 Jacques:
Discovered by amateur astronomer Cristovao Jacques on March 13th of this year from the SONEAR Observatory in Brazil, Comet E2 Jacques has been dazzling observers as it passed 35 degrees from the north celestial pole and posed near several deep sky wonders as it transited the constellation of Cassiopeia.
Comet E2 Jacques on August 28th as seen from the MVAS dark sky site in Yellow Springs, Ohio. Credit: John Chumack.
Mid-September finds Jacques 55 degrees above the NE horizon at dusk for northern hemisphere viewers in the constellation Cygnus. It then races southward parallel to the galactic equator, keeping in the +7th to +8th magnitude range before dropping down below +10th magnitude in late October. After this current passage through the inner solar system, Comet Jacques will be on a shortened 12,000 year orbit.
-Brightest: Mid-August at +6th magnitude.
-Perihelion: July 2nd, 2014 (0.66 AU).
-Closest to Earth: August 28, 2014 (0.56 AU).
Some key upcoming dates:
Sep 10: Passes the +3.9 magnitude star Eta Cygni.
Sep 14: Passes near the famous optical double star Albireo and crosses into the constellation of Vulpecula.
Sep 16: Passes in front of the +4.4 magnitude star Alpha Vulpeculae.
Sep 20: Crosses the Coathanger asterism.
Sep 21: Crosses into the constellation Sagitta.
Sep 24: Crosses into Aquila.
The celestial path of Comet Jacques from September 12th through November 1st. (All simulations created using Starry Night Education software.
Oct 5: Crosses the galactic plane.
Oct 14: passes near the +7.5 magnitude open cluster NGC 6755.
Oct 15: Drops back below +10th magnitude?
C/2013 V5 Oukaïmeden
Pronounced Ow-KAY-E-Me-dah, (yes, it’s a French name, with a very metal umlaut over the “ï”!) comet C/2013 V5 Oukaïmeden was discovered by the Moroccan Oukaïmeden Sky Survey (MOSS) located in the Atlas Mountains in Morocco. After completing a brief dawn appearance in early September, the comet moves into the dusk sky and starts the month of October located 38 degrees east of the Sun at about 14 degrees above the southwestern horizon as seen from latitude 30 degrees north at sunset. Southern hemisphere observers will continue to have splendid dawn views of the comet through mid-September at its expected peak. Comet Oukaïmeden is currently at +8th magnitude “with a bullet” and is expected to top out +6th magnitude in late September shortly before perihelion and perhaps remain a binocular object as it crosses the constellation Libra in October.
An early image of Comet C/2013 V5 Oukaimeden taken in February of this year. Credit: Efrain Morales Rivera.
And its also worth noting that as comet A1 Siding Spring (see below) makes a close physical pass by Mars on October 19th, Comet Oukaïmeden makes a close apparent pass by Saturn as seen from our Earthly vantage point the evening before! To be sure, the dusk apparition of Comet Oukaïmeden will be a tough one, but if you can track down these bright guidepost objects listed below, you’ll have a chance at spying it.
-Brightest: Mid-September.
-Perihelion: September 28th, 2014 (0.63 AU from the Sun).
-Closest to Earth: September 16th, 2014 (0.48 AU).
Some key upcoming dates:
Sep 10 through Oct 4: Threads across the borders of the constellations Hydra, Pyxis, Antlia and Centaurus.
Sep 18: Passes near the +3.5 magnitude star Xi Hydrae.
Sep 19: Passes near the +4.3 magnitude star Beta Hydrae.
Sep 25: Passes 1.5 degrees from the +8th magnitude Southern Pinwheel Galaxy M83.
Oct 1: Passes in front of the +10.2 globular cluster NGC 5694.
The path of Comet Oukaimeden through the month of October: The Sun position is shown for the final date.
Oct 3: Passes into Libra.
Oct 11: Passes near the +8.5 magnitude globular cluster NGC 5897.
Oct 16: Crosses the ecliptic plane northward.
Oct 18: Passes less than two degrees from Saturn.
Oct 25: Passes less than a degree from the 2 day old Moon and the +3.9 magnitude star Gamma Librae.
The projected light curve for Comet Oukaimeden with observational measurements (black dots). Credit: Seiichi Yoshida.
C/2013 A1 Siding Spring
This comet was discovered on January 3rd, 2013 from the Siding Spring observatory in Australia, and soon caught the eye of astronomers when it was discovered that it would make a nominal pass just 139,000 kilometres from Mars on October 19th.
Comet A1 Siding Spring as seen from NEOWISE early this year. Credit: NASA/JPL.
As seen from the Earth, Comet A1 Siding Spring has just broken 10th magnitude and vaults up towards the planet Mars low to the southwest at dusk this Fall for northern hemisphere observers. A1 Siding Spring is expected to top out at +8th magnitude this month before its Mars encounter, and is on a one million year plus orbit.
-Brightest: Early to Mid-September.
-Perihelion: October 25th, 2014.
-Closest to Earth: October 28th, 2014 (1.4 AU).
Some key upcoming dates:
Sep 17: Passes into the constellation Telescopium.
Sep 20: Passes near the +8.5 magnitude globular NGC 6524.
Sep 21: Passes into the constellation Ara.
Sep 22: Passes the +3.6 magnitude star Beta Arae.
Sep 25: Crosses into Scorpius.
Sep 30: Passes the +3 magnitude star Iota Scorpii.
Mars and Comet A1 Siding Springs crossing paths through the month of October.
Oct 3: Passes near the +7.2 magnitude globular NGC 6441.
Oct 5: Passes 2 degrees from Ptolemy’s cluster M7.
Oct 8: Passes in front of the Butterfly cluster M6.
Oct 10: Crosses the galactic plane.
Oct 11: Crosses into Ophiuchus.
Oct 19: Passes just 2’ arc minutes from Mars as seen from Earth.
Oct 22: Passes north of the ecliptic.
Oct 30: Drops back below +10th magnitude?
Key moonless windows for evening comet viewing as reckoned from when the Moon wanes from Full to New are: September 9th to September 24th and October 8th to the 23rd.
Looking for resources to find out just what these comets and others are up to? The COBS Comet Observers database is a great resource for recent observations, as is Seiichi Yoshida’s Weekly Comet page. For history and current info, Gary Kronk’s Cometography is also a great treasure trove to delve into, as are the Yahoo! Comet and Comet Observer mailing lists.
Be sure to check out these fine icy visitors to the inner solar system coming to a sky near you. We fully expect to see more outstanding images of these comets and more filling up the Universe Today Flickr forum!
