Artist's conception of the Pluto system from the surface of one of its moons. Credit: NASA, ESA and G. Bacon (STScI)
When you have a spacecraft that takes the better part of a decade to get to its destination, it’s really, really important to make sure you have an accurate fix on where it’s supposed to be. That’s true of the Rosetta spacecraft (which reached its comet today) and also for New Horizons, which will make a flyby past Pluto in 2015.
To make sure New Horizons doesn’t miss its big date, astronomers are using the Atacama Large Millimeter/submillimeter Array (ALMA) to figure out its location and orbit around the Sun. You’d think that we’d know where Pluto is after decades of observations, but because it’s so far away we’ve only tracked it through one-third of its 248-year orbit.
“With these limited observational data, our knowledge of Pluto’s position could be wrong by several thousand kilometers, which compromises our ability to calculate efficient targeting maneuvers for the New Horizons spacecraft,” stated Hal Weaver, a New Horizons project scientist at Johns Hopkins University Applied Physics Laboratory in Maryland.
Pluto’s moon Charon moves around the dwarf planet in this animated image based on the data from the Atacama Large Millimeter/submillimeter Array (ALMA). Credit: B. Saxton (NRAO/AUI/NSF)
As ALMA is a radio/submillimeter telescope, the array picked up Pluto and its largest moon, Charon, by looking at the radio emission from their surfaces. They examined the objects in November 2013, in April 2014 and twice in July. More observations are expected in October.
“By taking multiple observations at different dates, we allow Earth to move along its orbit, offering different vantage points in relation to the Sun,” stated Ed Fomalont, an astronomer with the National Radio Astronomy Observatory who is assigned to ALMA’s operations support facility in Chile. “Astronomers can then better determine Pluto’s distance and orbit.”
New Horizons will reach Pluto in July 2015, and Universe Today is planning a series of articles about the dwarf planet. We’ll need your support to get it done, though. Check out the details here.
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
This fall, Universe Today plans to get in-depth into the Pluto planethood debate. I (Elizabeth Howell) just launched a crowdfunding project on a new platform called Beacon that will allow me to fly down to Washington, D.C. for several days to interview Pluto scientists.
Should the project be funded, a few fun things are going to happen. Here, Universe Today readers will get a series of articles into the Pluto planethood debate. We’ll examine the controversial International Astronomical Union vote and why certain scientists still don’t believe Pluto is a dwarf planet today.
The question has special relevance today because NASA’s New Horizons spacecraft is on a journey to Pluto, and is less than a year from getting there. Examining Pluto will give scientists a window into how the solar system formed, which in turn gives us clues as to how the Earth came to be. We’ll have some stuff about the science as well; stay tuned for the details!
You’ll also get the chance to support astronomy education and outreach. I’m pleased to announce that CosmoQuest will be a partner on the project, receiving 15% of all proceeds for the project. If you contribute $250, $500 or $1,000, they will receive an additional 15% of your money. Contributors at this level will have their name mentioned in at least two of a series of six podcasts I will do for CosmoQuest’s 365 Days of Astronomy. There are other fun perks, too, so check out the Beacon page for more.
As a freelance journalist, my challenge with doing travel stories is I have to pay my own way. Beacon solves that problem. It will allow me to spend a few days in person with scientists, gathering pictures and videos and podcasts, instead of relying on the phone interviews I usually conduct.
After paying contributions to CosmoQuest and to Beacon, every single cent remaining will be for travel expenses only. The money will give me a flight to Washington, D.C., a few nights in a reasonable hotel, and a car rental. I promise you that I’m extremely frugal — ask my mortgage broker — and I will spend every dollar of your contributions wisely. Additional money after $2,400 will allow me to draw a salary for the days I am there. If a substantial amount of extra money is raised, I’ll consider a second trip to D.C.
A NASA “poster” marking the one year to Pluto encounter by New Horizons. Credit: NASA
I’m not one to brag about my experience, but I will say that I’ve been proudly writing about space for a decade for many publications (including Universe Today). I’m one of the few journalists in Canada to focus on space virtually full-time. And I have covered some fun stories, such as three shuttle launches (2009-10), Chris Hadfield’s last mission (2012-13) and participating in a simulated Mars mission in Utah (early 2014). I see space as a field where I can always learn more, and this will be a great chance to share what I learn about Pluto with you.
Any questions? Feel free to get in touch with me at contact AT elizabethhowell DOT ca or to leave comments below. I likely won’t be able to respond until tomorrow as this launch coincidentally falls on a planned vacation day for me, but I promise that for the rest of the campaign I’ll answer your queries as fast as I can.
A NASA "poster" marking the one year to Pluto encounter by New Horizons. Credit: NASA
Countdown! Just under one year from now, the New Horizons will finally reach its mission goal after sailing through the solar system for the better part of a decade. It will fly by the dwarf planet Pluto and its moons on July 14, 2015, showing us the surface of these distant bodies for the very first time.
And the New Horizon’s team reported a thruster burn yesterday has put the spacecraft right on course to correct the spacecraft’s arrival time – a year from now – at the precisely intended aim point at Pluto.
The spacecraft fired its thrusters for just under 88 seconds, which sped the craft up by about 3.8 km/h (2.4 miles per hour.)
“If we hadn’t performed this maneuver, we would have arrived at Pluto about 36 minutes later than we wanted to,” said Mark Holdridge, New Horizons encounter mission manager. “Making the adjustment now means we won’t have to perform a bigger maneuver – and use more of the spacecraft’s fuel – down the road.”
“It was a great burn, performed flawlessly” said Alan Stern, New Horizons principal investigator. “You could say that New Horizons just lit a little candle for its one year out anniversary.”
It was the spacecraft’s sixth course correction maneuver since launch in January 2006, and the first since 2010.
“Pluto gets closer by the day, and New Horizons continues into rare territory, as just the fifth probe to traverse interplanetary space so far from the sun,” said NASA on the New Horizon’s website. “And the first ever to travel to Pluto.”
It’ll be a treat to see what the dwarf planet looks like after so many tantalizing glimpses by the Hubble Space Telescope and New Horizons spacecraft itself (see this story from last week for some views.) Happy sailing!
Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASA
The Sagittarius Spoon with dwarf planet Pluto (14.1 Mag) crossing the star fields of Sagittarius.
The arrow points to the location of Pluto. Image taken from Dexter, Iowa on June 29, 2014 around 3:50 am local time. Credit and copyright: John Chumack.
Last week, we encouraged those of you with a decent sized backyard telescope (and a little patience) to try and spot tiny dwarf planet Pluto, which was at opposition over this past weekend.
One of our favorite astrophotographers, John Chumack, did just that using the “Sagittarius Spoon” to zero-in on Pluto’s location.
“Most astronomers are familiar with the Great Tea Pot of Sagittarius, but just above the Teapot’s Handle is the Sagittarius Spoon!” John said via email. His annotated image, above, shows the spoon and the arrow points to Pluto.
See a non-annotated version, below, and try to also spot some very familiar deep sky objects in this field of view:
A non-annotated version of the Sagittarius Spoon and Pluto on 06-29-2014 from Dexter, Iowa. Credit and copyright: John Chumack.
Can you see:
Globular Clusters M22, M28, NGC-6717
Open Star Clusters M25, M18
Emission Nebulae M17 The Swan or Omega Nebula & M16 The Eagle Nebula
M24 The Sagittarius Star Cloud, (also awesome in binoculars, John says)
John used a modified Canon 40D DSLR & 50mm lens @F5.6, ISO 1600 for a Single 4 minute exposure while tracking on a CG-4 Mount. And friends from Dexter, Iowa provided the view!
Update:
Larry McNish from the Calgary Centre of the Royal Astronomical Society of Canada also sent in two images of Pluto at opposition. All the details are on the images, but they emphasize just how difficult capturing Pluto can be:
Pluto two days before opposition on July 2, 2014. Credit and copyright: Larry McNish, Calgary Centre of the Royal Astronomical Society of Canada.Pluto, four days after opposition on July 8, 2014. Credit and copyright: Larry McNish, Calgary Centre of the Royal Astronomical Society of Canada.
Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
After almost nine years on the road, New Horizons is in what NASA calls “Pluto-space”! Earlier today (July 7), the spacecraft Twitter account announced New Horizons is now 29.8 Earth-sun distances (astronomical units) away from the Sun, putting it within the boundaries of Pluto’s eccentric orbit — exciting, since Pluto is the primary science target.
“Didn’t get the word? We’re farther out than Pluto’s minimum distance to the Sun. We’re in ‘Pluto-space’ now!” tweeted the New Horizons account. We’ve included some of the best Pluto pictures below, to date, to celebrate.
And while many are focused on the Pluto encounter itself, NASA is already planning for what to do next for the spacecraft. In mid-June, we reported that the Hubble Space Telescope was doing a test search for icy Kuiper Belt objects that New Horizons could possibly fly to next.
That test search was successful enough, with two objects found, that Hubble is now doing a full-blown investigation, according to an announcement last week. Hubble will begin that work in July and conclude observations in August. New Horizons is expected to fly by Pluto and its moons in July 2015.
Pluto’s surface as viewed from the Hubble Space Telescope in several pictures taken in 2002 and 2003. Though the telescope is a powerful tool, the dwarf planet is so small that it is difficult to resolve its surface. Astronomers noted a bright spot (180 degrees) with an unusual abundance of carbon monoxide frost. Credit: NASAPluto and its moons, most of which were discovered while New Horizons was in development and en route. Charon was found in 1978, Nix and Hydra in 2005, Kerberos in 2011 and Styx in 2012. The New Horizons mission launched in 2006. Picture taken by the Hubble Space Telescope. Credit: NASAPluto and moons Charon, Hydra and Nix (left) compared to the dwarf planet Eris and its moon Dysnomia (right). This picture was taken before Kerberos and Styx were discovered in 2011 and 2012, respectively. Credit: International Astronomical UnionPluto appears as a faint white dot (see arrow) in this image taken by New Horizons in September 2006, nine months after launch. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research InstitutePluto and Charon are visible in this 2013 image from New Horizons’ LOng Range Reconnaissance Imager (LORRI). It was the first image from the spacecraft showing Charon separated from Pluto. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Pluto passing near the star cluster M25 in late 2013. Credit: Dave Walker.
Are you ready for 2015? On July 14th, 2015 — just a little over a year from now — NASA’s New Horizons spacecraft with perform its historic flyby of Pluto and its retinue of moons. Flying just 10,000 kilometres from the surface of Pluto — just 2.5% the distance from Earth to the Moon on closest approach — New Horizons is expected to revolutionize our understanding of these distant worlds.
And whether you see Pluto as a much maligned planetary member of the solar system, an archetypal Plutoid, or the “King of the Kuiper Belt,” you can spy this denizen of the outer solar system using a decent sized backyard telescope and a little patience.
New Horizons in the clean room having its plutonium-fueled MMRTG installed. (Credit: NASA).
Pluto reaches opposition for 2014 later this week on Friday, July 4th at 3:00 Universal Time (UT), or 11:00 PM EDT on July 3rd. This means that Pluto will rise to the east as the Sun sits opposite to it in the west at sunset and transits the local meridian high to the south at local midnight. This is typically the point of closest approach to Earth for any outer solar system object and the time it is brightest.
The location of Pluto at dusk on July 4th, the night of opposition. Credit: Stellarium.
But even under the best of circumstances, finding Pluto isn’t easy. Pluto never shows a resolvable disk in even the largest backyard telescope, and instead, always appears like a tiny star-like point. When opposition occurs near perihelion — as it last did in 1989 — Pluto can reach a maximum “brilliancy” of magnitude +13.6. However, Pluto has an extremely elliptical orbit ranging from 30 to 49 Astronomical Units (A.U.s) from the Sun. In 2014, Pluto has dropped below +14th magnitude at opposition as it heads back out towards aphelion one century from now in 2114.
The path of Pluto from July to December 2014. Created using Starry Night Education Software.
Another factor that makes finding Pluto challenging this decade is the fact that it’s crossing through the star-rich plane of the galaxy in the direction of the constellation Sagittarius until 2023. A good finder chart and accurate pointing is essential to identifying Pluto as it moves 1’ 30” a day against the starry background from one night to the next.
In fact, scouring this star-cluttered field is just one of the challenges faced by the New Horizons team as they hunt for a potential target for the spacecraft post-Pluto encounter. But this has also meant that Pluto has crossed some pretty photogenic regions of the sky, traversing dark Bok globules and skirting near star clusters.
Pluto (marked) imaged by Jim Hendrickson @SkyscraperJim on the morning of June 28th.
You can use this fact to your advantage, as nearby bright stars make great “guideposts” to aid in your Pluto-quest. Pluto passes less than 30” from the +7th magnitude pair BB Sagittarii on July 7th and 8th and less than 3’ from the +5.2 magnitude star 25 Sagittarii on July 21st… this could also make for an interesting animation sequence.
Though Pluto has been reliably spotted in telescopes as small as 6” in diameter, you’ll most likely need a scope 10” or larger to spot it. We’ve managed to catch Pluto from the Flandrau observatory situated in downtown Tucson using its venerable 14” reflector.
The path of Pluto June 28th-August 8th. (click here for an inverted white background view). Created using Starry Night Education Software.
Pluto was discovered by Clyde Tombaugh from the Lowell Observatory in 1930 while it was crossing the constellation Gemini. It’s sobering to think that it has only worked its way over to Sagittarius in the intervening 84 years. It was also relatively high in the northern hemisphere sky and headed towards perihelion decades later during discovery. 2014 finds Pluto at a southern declination of around -20 degrees, favoring the southern hemisphere. Had circumstances been reversed, or Pluto had been near aphelion, it could have easily escaped detection in the 20th century.
We’re also fortunate that Pluto is currently relatively close to the ecliptic plane, crossing it on October 24th, 2018. Its orbit is inclined 17 degrees relative to the ecliptic and had it been high above or below the plane of the solar system, sending a spacecraft to it in 2015 might have been out of the question due to fuel constraints.
The current location of New Horizons. (Credit: NASA/JPL).
And speaking of spacecraft, New Horizons now sits less than one degree from Pluto as seen from our Earthly vantage point. And although you won’t be able to spy this Earthly ambassador with a telescope, you can wave in its general direction on July 11th and 12th, using the nearby waxing gibbous Moon as a guide:
The Moon, Pluto and New Horizons as seen on July 11th. (Created Using Starry Night Education Software).
All eyes will be on Pluto and New Horizons in the coming year, as it heads towards a date with destiny… and we’ll bet that the “is Pluto a planet?” debate will rear its head once more as we get a good look at these far-flung worlds.
And hey, if nothing else, us science writers will at last have some decent pics of Pluto to illustrate articles with, as opposed to the same half-dozen blurry images and artist’s renditions…
Artist's impression of New Horizons' encounter with Pluto and Charon. Credit: NASA/Thierry Lombry
It’s going to be a really busy summer for the New Horizons team. While they’re checking out the newly awakened spacecraft to make sure it’s working properly for its close encounter with Pluto next year, NASA is already thinking about where to put it next: possibly towards a Kuiper Belt Object!
So now the Hubble Space Telescope (in Earth orbit) is scoping out icy objects beyond Pluto. Luckily for us, one of the team members — Alex Parker, a planetary astronomer at the University of California, Berkeley, provided an entertaining livetweet of the process — even through a power failure.
So, the secret is out. On Friday, we were awarded the Hubble time to search for a @NewHorizons2015 KBO target!
There’s far more to Parker’s tweets than we are indicating here; his Twitter feed also has details about the collaborators, for example, so be sure to read through the entire exchange from yesterday. The survey is led by the Southwest Research Institute’s John Spencer.
What astronomers are doing now is a “pilot observation” where the space telescope looks at a spot in the constellation Sagittarius. Controllers will try to turn the telescope at the same rate as what a KBO would be orbiting around the sun. If the method works, stars will look like streaks and the KBOs will look like “pinpoint objects”, NASA stated.
A view of the Hubble Space Telescope from inside space shuttle Atlantis on mission STS-125 in 2009. Credit: NASA
“If the test observation identifies at least two KBOs of a specified brightness it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full moon,” NASA said in a press release.
The reason for this step is Hubble is a high-profile telescope, receiving a lot of requests for observing time around the world. The agency wants to ensure that the telescope is being used for the best scientific return possible. NASA also noted the search might be difficult.
“Though Hubble is powerful enough to see galaxies near the horizon of the universe, finding a KBO is a challenging needle-in-haystack search. A typical KBO along the New Horizons trajectory may be no larger than Manhattan Island and as black as charcoal,” NASA stated.
This isn’t the first time the telescope has done a pinch-hit for Plutonian science. Four new moons have been found around Pluto, a discovery that involved Hubble time. The telescope has also looked for dust rings near the dwarf planet (to do a risk analysis for New Horizons’ approach) and done a map of the surface, to help controllers figure out where to target New Horizons.
Artist's impression of the New Horizons spacecraft. Image Credit: NASA
While many kids in the U.S. are starting their school summer vacations, New Horizons is about to get back to work! Speeding along on its way to Pluto the spacecraft has just woken up from hibernation, a nap it began five months (and 100 million miles) ago.
The next time New Horizons awakens from hibernation in December, it will be beginning its actual and long-awaited encounter with Pluto! But first the spacecraft and its team have a busy and exciting summer ahead.
New Horizons tweeted about its Father’s Day wakeup call
After an in-depth checkout of its onboard systems and instruments, the New Horizons team will “track the spacecraft to refine its orbit, do a host of instrument calibrations needed before encounter, carry out a small but important course correction, and gather some cruise science,” according to principal investigator Alan Stern in his June 11 update, aptly titled “Childhood’s End.”
What’ll be particularly exciting for us space fans is an animation of Pluto and Charon in motion around each other, to be made from new observations to be acquired in July. Because of New Horizons’ position, the view will be from a perspective not possible from Earth.
New Horizons LOng Range Reconnaissance Imager (LORRI) image of Pluto and Charon from July 2013 (Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
The next major milestone for New Horizons will be its crossing of Neptune’s orbit on August 25. (This just happens to fall on the 25th anniversary of Voyager 2’s closest approach in 1989.) “After that,” Stern says, “we’ll be in ‘Pluto space!'”
Launched on Jan. 19, 2006, New Horizons will make its closest approach to Pluto on July 14, 2015 at 11:49 UTC. Traveling nearly 35,000 mph (55,500 km/h) it’s one of the fastest vehicles ever built, moving almost 20 times faster than a bullet.
Read more from Alan Stern in his latest “PI Perspective” article on the New Horizons web site here, and check out NASA’s mission page here for the latest news as well.
“There is a lot to tell you about over the next 12 weeks, and this is just the warm-up act. Showtime — the start of the encounter — begins in just six months. This is what New Horizons was built for, and what we came to do. In a very real sense, the mission is emerging into its prime.”
– Alan Stern, New Horizons principal investigator
Also, check out a video on Pluto and the New Horizons mission here.
It’s a lot of speculation right now, but the buzz in a new NASA study is Pluto’s largest moon (Charon) could have a cracked surface.
If the New Horizons mission catches these cracks when it whizzes by in 2015, this could hint at an ocean underneath the lunar surface — just like what we talk about with Europa (near Jupiter) and Enceladus (near Saturn). But don’t get too excited — it’s also possible Charon had an ocean, but it froze out over time.
“Our model predicts different fracture patterns on the surface of Charon depending on the thickness of its surface ice, the structure of the moon’s interior and how easily it deforms, and how its orbit evolved,” stated Alyssa Rhoden of NASA’s Goddard Space Flight Center in Maryland, who led the research.
“By comparing the actual New Horizons observations of Charon to the various predictions, we can see what fits best and discover if Charon could have had a subsurface ocean in its past, driven by high eccentricity.”
It seems an unlikely proposition given that Pluto is so far from the Sun — about 29 times further away than the Earth is. Its surface temperature is -380 degrees Farhenheit (-229 degrees Celsius), which — to say the least — would not be a good environment for liquid water on the surface.
But it could happen with enough tidal heating. To back up, both Europa and Enceladus are small moons fighting gravity from their much larger gas giant planets, not to mention a swarm of other moons. This “tug-of-war” not only makes their orbits eccentric, but creates tides that change the interior and the surface, causing the cracks. Perhaps this might have kept subsurface oceans alive on these moons.
Encaladus, a moon of Saturn, as shown in this Voyager 1 image. Credit: NASA
Since Charon once had an eccentric orbit, perhaps it also had tidal heating. Scientists think that the moon was created after a large object smacked into Pluto and created a chain of debris (similar to the leading theory for how our Moon was formed). The proportionally huge Charon — it’s one-eighth Pluto’s mass — would have been close to its parent planet, causing gravity to tug on both objects and creating friction inside their interiors.
“This friction would have also caused the tides to slightly lag behind their orbital positions,” NASA stated. “The lag would act like a brake on Pluto, causing its rotation to slow while transferring that rotational energy to Charon, making it speed up and move farther away from Pluto.”
But this friction would have ceased long ago, given that observations show Charon orbits in a stable circle further away from Pluto, and there are no extraneous tugs on its path today. So another possibility is there was an ocean beneath the moon’s surface that today is a block of ice.
An artist’s conception of a KBO encounter by New Horizons. Credit: JHUAPL/SwRI.
Are you ready for the summer of 2015? A showdown of epic proportions is in the making, as NASA’s New Horizons spacecraft is set to pass within 12,500 kilometres of Pluto — roughly a third of the distance of the ring of geosynchronous satellites orbiting the Earth — a little over a year from now on July 14th, 2015.
But another question is already being raised, one that’s assuming center stage even before we explore Pluto and its retinue of moons: will New Horizons have another target available to study for its post-Pluto encounter out in the Kuiper Belt? Researchers say time is of the essence to find it.
To be sure, it’s a big solar system out there, and it’s not that researchers haven’t been looking. New Horizons was launched from Cape Canaveral Air Force Station on January 19th, 2006 atop an Atlas V rocket flying in a 551 configuration in one of the fastest departures from Earth ever: it took New Horizons just nine hours to pass Earth’s moon after launch.
New Horizons spends its last days on Earth pre-encapsulation. (Credit: NASA/KSC).
The idea has always been out there to send New Horizons onward to explore and object beyond Pluto in the Kuiper Belt, but thus far, searches for a potential target have turned up naught.
A recent joint statement from NASA’s Small Bodies and Outer Planets Assessment Groups (SBAG and OPAG) has emphasized the scientific priority needed for identifying a possible Kuiper Belt Object (KBO) for the New Horizons mission post-Pluto encounter. The assessment notes that such a chance to check out a KBO up close may only come once in our lifetimes: even though it’s currently moving at a heliocentric velocity of just under 15 kilometres a second, it will have taken New Horizons almost a decade to traverse the 32 A.U. distance to Pluto.
The report also highlights the fact that KBOs are expected to dynamically different from Pluto as well and worthy of study. The statement also notes that the window may be closing to find such a favorable target after 2014, as the upcoming observational apparition of Pluto as seen from Earth — and the direction New Horizons is headed afterwards — reaches opposition this summer on July 4th.
But time is of the essence, as it will allow researchers to plan for a burn and trajectory change for New Horizons shortly after its encounter with Pluto and Charon using what little fuel it has left. Then there’s the issue of debris in the Pluto system that may require fine-tuning its trajectory pre-encounter as well. New Horizons will begin long range operations later this year in November, switching on permanently for two years of operations pre-, during and post- encounter with Pluto.
And there currently isn’t a short-list of “next best thing” targets for New Horizons post-Pluto encounter. One object, dubbed VNH0004, may be available for distant observations in January of next year, but even this object will only pass 75 million kilometres — about 0.5 A.U. — from New Horizons at its closest.
Ground based assets such as the Keck, Subaru and Gemini observatories have been repeatedly employed in the search over the past three years. The best hopes lie with the Hubble Space Telescope, which can go deeper and spy fainter targets.
Nor could New Horizons carry out a search for new targets on its own. Its eight inch (20 cm in diameter) LORRI instrument has a limiting magnitude of about +18, which is not even close to what would be required for such a discovery.
New Horizons currently has 130 metres/sec of hydrazine fuel available to send it onwards to a possible KBO encounter, limiting its range and maneuverability into a narrow cone straight ahead of the spacecraft. This restricts the parameters for a potential encounter to 0.35 A.U. off of its nominal path for a target candidate be to still be viable objective. New Horizons will exit the Kuiper Belt at around 55 A.U. from the Sun, and will probably end its days joining the Voyager missions probing the outer solar system environment. Like Pioneers 10 and 11, Voyagers 1 and 2 and the upper stage boosters that deployed them, New Horizons will escape our solar system and orbit the Milky Way galaxy for millions of years. We recently proposed a fun thought experiment concerning just how much extraterrestrial “space junk” might be out there, littering the galactic disk.
And while the crowd-sourced Ice Hunters project generated lots of public engagement, a suitable target wasn’t found. There is talk of a follow up Ice Investigators project, though it’s still in the pending stages.
Another issue compounding the problem is the fact that Pluto is currently crossing the star rich region of the Milky Way in the constellation Sagittarius. Telescopes looking in this direction must contend with the thousands of background stars nestled towards the galactic center, making the detection of a faint moving KBO difficult. Still, if any telescope is up to the task, it’s Hubble, which just entered its 25th year of operations last month.
The path of Pluto through the constellation Sagittarius through August 2015. Credit: Starry Night.
Shining at +14th magnitude, Pluto will be very near the 3.5th magnitude star Xi2 Sagittarii during the July 2015 encounter.
New Horizons is currently 1.5 degrees from Pluto — about 3 times the angular size of a Full Moon —as seen from our Earthly vantage point, and although neither can be seen with the naked eye, you can wave in their general direction this month on May 18th, using the nearby daytime Moon as a guide.
The waning crescent Moon lies in the direction of New Horizons and Pluto on May 18th… note the ESA’s Rosetta spacecraft (lower left) and Pioneer 11 (upper center) are also ‘nearby!’ Credit: Starry Night
July 2015 will be an exciting and historic time in solar system exploration. Does Pluto have more undiscovered moons? A ring system of its own? Does it resemble Neptune’s moon Triton, or will it turn out looking entirely different ?
If nothing else, exploration of Pluto will finally give us science writers some new images to illustrate articles on the distant world, rather than recycling the half a dozen-odd photos and artist’s conceptions that are currently available. An abundance of surface features will then require naming as well. It would be great to see Pluto’s discoverer Clyde Tombaugh and Venetia Burney — the girl who named Pluto — get their due. We’ll even assume our space pundit’s hat and predict a resurgence of the “is it a planet?” debate once again in the coming year as the encounter nears…
