Institute for Astronomy / University of Hawaii / PANSTARRS
Discovery image of the newfound comet C/2011 L4 (PANSTARRS), taken by Hawaii's PANSTARRS 1 telescope.
By
updated 4/2/2012 1:37:48 PM ET 2012-04-02T17:37:48

A year from now, it is possible that "comet fever" will be running high when a newfound comet emerges into view in the evening sky. But while some scientists have high hopes for a spectacular 2013 sky show by the comet, it is still far from certain.

When astronomers at the University of Hawaii at Manoa announced last June that they had discovered the new comet, it was a distant and inconspicuous object. But preliminary calculations at once made it clear that this new object had the potential to become a naked-eye object of considerable interest for skywatching enthusiasts in the Northern Hemisphere. The comet may ultimately shine as bright as some of the brightest stars in the night sky, but will likely pale in comparison to the brilliant planet Venus.

The comet was christened C/2011 L4 (PANSTARRS). Comets are usually named after their discoverers, but in this case a large team of observers, computer scientists, and astronomers was involved, so the comet was named after the telescope.

PANSTARRS stands for Panoramic Survey Telescope And Rapid Response System. It's a 1.8-meter prototype for a quartet of military-funded telescopes that astronomers hope to build on the lip of the extinct volcano Haleakala.

Finding Comet PANSTARRS
The comet was initially photographed on June 6 and was confirmed the following day. Actually, the comet had been unknowingly imaged nearly two weeks earlier, on May 24 from Arizona’s Mount Lemmon Observatory. [ Amazing Photos of Halley's Comet ]

When it was discovered in the constellation Libra, Comet PANSTARRS was a 19th-magnitude object — so faint that only telescopes with sensitive electronic detectors could pick it up — some 759 million miles (1.2 billion kilometers) from the sun.

Astronomers measure the brightness of objects in space on a reverse scale; the higher an object's magnitude, the dimmer it appears to observers. The comet was so far away that at first there was difficulty in pinning down the exact date of when it would arrive at perihelion – its closest point to the sun. Initial estimates suggested anytime from early next February to the middle of April of 2013. 

When I first wrote about comet PANSTARRS June 27 of last year, the date of perihelion was set for next April 17. But I also said at the time: “It may yet change again, so stay tuned.”

And so it did, to March 9, 2013 — less than one year from today.

The comet will pass to within 28 million miles (45 million kilometers) of the sun on that date. Such an enormous change in solar distance would cause a typical comet to increase in brightness dramatically. And indeed, the comet has responded to the increasing solar warmth as it has approached the sun. 

On Feb. 13, the comet had brightened to magnitude 14.5, or in other words, it had increased in brightness by more than 60 times since it was first seen last June. The comet still has a long way to go — it’s still more than 500 million miles (820 million km) from both the sun and Earth — out near the orbit of Jupiter. But it still appears on target to possibly become a bright naked eye object by this time next year.

Rob Ratkowski
The PS1 Observatory on Haleakala, Maui just before sunrise.
  

How bright could Comet PANSTARRS get?
Just how bright Comet PANSTARRS will ultimately be still cannot be reliably predicted. 

Estimates (or maybe really "guesstimates") suggest that at perihelion on March 9, the comet might become as bright as zero magnitude, placing it in the same rank as the stars Arcturus, Vega and Capella; which are some of the brightest stars in the sky. Thereafter, the comet's rapid northward motion, owing to its orbital inclination of 84 degrees to the plane of the solar system, will gradually carry it away from the sun and into the western evening sky. 

If there is a significant tail, it would probably be seen protruding almost straight up and perhaps tilted slightly to the right, relative to the horizon.  But as is the case with the comet’s brightness, we can only guess just how long it will be. [ Best Comet Close Encounters Ever ]

In the week following its closest approach to the sun, the head of the comet will be positioned less than 6 degrees above the horizon during late-twilight; about an hour or so after sunset. You can measure how low this is by recalling that your clenched fist held at arm’s length measures roughly 10 degrees in width. 

So Comet PANSTARRS will be only about "half a fist" above the horizon as the sky is getting appreciably dark.

On the evening of March 12, the slender sliver of a crescent moon, just one day past new, will be positioned less than 5 degrees to the right of the comet, making for perhaps a very picturesque scene. Prospective observers will need to seek the most favorable conditions possible. 

Even a potentially bright comet, like this one, can be easily obliterated by thin horizon clouds, haze, humid air, smoke, sunset glow or city lights. Binoculars or a small telescope are recommended for locating both the moon and the comet.

Skywatching treat of comet PANSTARRS
On successive evenings in March 2013, comet PANSTARRS will grow fainter, it will continue to get farther from the sun, setting later and visible in a darker sky. During April, the comet will become well placed for observing with small telescopes ; on the evenings of April 2 and 3 it will be sliding within a couple of degrees of the Great Andromeda Galaxy. 

By mid-April the comet will become circumpolar — that is, it will remain above the horizon all night as seen from mid-northern latitudes; during late April it will appear to pass through the famous "W" of Cassiopeia.

The only possible drawback to a possible bright apparition of this comet is the fact that even after more than 200 precise positions; the orbit of comet PANSTARRS does not differ significantly from a parabola.  In other words, it may never have passed near the sun before.

  1. Space news from NBCNews.com
    1. KARE
      Teen's space mission fueled by social media

      Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

    2. Buzz Aldrin's vision for journey to Mars
    3. Giant black hole may be cooking up meals
    4. Watch a 'ring of fire' solar eclipse online

That's bad news, because we believe that such comets might be covered with very volatile materials such as frozen nitrogen, carbon monoxide and carbon dioxide. These ices vaporize far from the sun, giving a distant comet a short-lived surge in brightness that can raise very unrealistic expectations. 

If, on the other hand, PANSTARRS is making a return loop around the sun, then its highly volatile materials will have already been shed and what we’ll see in the months to come is the true underlying level of its activity.

All we say for sure at this point is that we have a much better idea of the path the comet is going to take in the coming weeks and months. Unless it begins to sputter out later this year, it’s still on track to become a celestial showpiece a year from now. We’ll keep an eye on it and continue to provide periodic updates as it gets closer to the sun. 

In the meantime, keep your fingers crossed!

If you snap an amazing photo of comet PANSTARRS or any other skywatching target, and would like to share it for a possible story or image gallery, please contact Space.com Managing Editor Tariq Malik at tmalik@space.com.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, N.Y.

© 2013 Space.com. All rights reserved. More from Space.com.

Photos: Month in Space: March 2012

loading photos...
  1. Partners in space

    A Russian Proton rocket carrying a US Intelsat-22 satellite blasts off from Kazakhstan's Russian-leased Baikonur cosmodrome on March 25. Intelsat 22 is a new satellite built by Boeing Space Systems for the Intelsat Corp. (AFP - Getty Images) Back to slideshow navigation
  2. Weightless winners

    Winners of the annual Red Bull Flugtag competition experience zero-gravity conditions during a flight in a cosmonaut training plane above the Moscow region on March 1. The flight was a prize awarded to the winners of last summer's competition, which required contestants to design, build and fly home-built aircraft. (Sergei Remezov / Reuters) Back to slideshow navigation
  3. Hello, world

    This image of the far side of the lunar surface, with Earth peeking up from the horizon, was taken by the MoonKAM system onboard the NASA GRAIL mission's Ebb spacecraft on March 17 and released on March 23. A little more than halfway up and on the left side of the image is the crater De Forest. The image is one of a set of pictures requested by students at Emily Dickinson Elementary School in Montana as part of the MoonKAM educational program. (NASA / SRS via Reuters) Back to slideshow navigation
  4. Aurora from above

    The southern lights glow green in a picture taken by Dutch astronaut Andre Kuipers on board the International Space Station between Antarctica and Australia on March 10. The station's lab modules and solar panels can be seen along the upper and right edges of the image. (NASA / Reuters) Back to slideshow navigation
  5. Heavenly lights

    Jonina Oskarsdottir captured this picture of the northern lights on March 8 over Faskrudsfjordur, Iceland. "No words can describe the experience of the northern lights tonight," Oskarsdottir told SpaceWeather.com. She used a Canon EOS 5D Mark II camera to take the shot, with a Canon 14mm f/2.8L USM II lens set for ISO 1600 ... and a 1-second exposure. (Jonina Oskarsdottir) Back to slideshow navigation
  6. Spirals in the sea

    Spectacular spirals of ice form in the sea surrounding Russia's Kamchatka Peninsula, in a picture taken by Dutch astronaut Andre Kuipers from the International Space Station on March 15. (André Kuipers / ESA/NASA) Back to slideshow navigation
  7. One giant leap

    Austrian skydiver Felix Baumgartner stands at the threshold of a balloon-borne capsule just before a test jump from a height of 71,500 feet. The successful test was conducted on March 15 over Roswell, N.M., in preparation for Baumgartner's planned supersonic jump from 120,000 feet. That feat would break a 52-year-old record for the highest parachute jump. (Jay Nemeth / Red Bull via Getty Images) Back to slideshow navigation
  8. Five-rocket fireworks

    A time-lapse photo shows the ascent of five suborbital sounding rockets from NASA's Wallops Flight Facility in Virginia on March 27. The launches were part of the Anomalous Transport Rocket Experiment, or ATREX, which was aimed at tracking high-altitude winds in the jet stream. The fiery display was visible along the East Coast from upstate New York and Massachusetts to North Carolina. (NASA) Back to slideshow navigation
  9. Infrared rainbow

    A false-color infrared image, released March 12, shows fledgling stars hidden among the gas and clouds of the Orion Nebula. The colors indicate different infrared wavelengths as detected by NASA's Spitzer Space Telescope and the European Space Agency's Herschel telescope. (NASA/ESA/JPL-Caltech/IRAM / EPA) Back to slideshow navigation
  10. Enter the Dragon

    NASA astronauts and industry experts check out the crew accommodations in SpaceX's Dragon spacecraft. On top, from left, are NASA Crew Survival Engineering Team Lead Dustin Gohmert, NASA astronauts Tony Antonelli and Lee Archambault, and SpaceX Mission Operations Engineer Laura Crabtree. On bottom, from left, are SpaceX Thermal Engineer Brenda Hernandez and NASA astronauts Rex Walheim and Tim Kopra. The Dragon is being developed for NASA's use as a cargo carrier as well as a crew vehicle. (SpaceX) Back to slideshow navigation
  11. Looking down at Luna

    This picture from NASA's Lunar Reconnaissance Orbiter, released March 14, shows Luna 17, the Soviet lander that carried the Lunokhod 1 rover to the surface in 1970. The debarking ramps for the rover are visible extending down to the surface to the right. Many rover tracks are visible around the lander. The inset picture provides a closeup look at Luna 17. (NASA/GSFC/ASU) Back to slideshow navigation
  12. The eye of Mars

    Radially oriented slope streaks paint stripes on the sides of this Martian crater in Arabia Terra. Slope streaks are common features on steep slopes in Mars' dusty terrain, but this crater is a particularly dramatic example. The picture was taken by the HiRISE camera on NASA's Mars Reconnaissance Orbiter and released on March 7. (NASA/JPL/University of Arizona) Back to slideshow navigation
  13. Eclipse in space

    The moon came between NASA's Solar Dynamics Observatory satellite and the sun, seen here in extreme ultraviolet light, on Feb. 28. SDO observed the partial solar eclipse for 1 hour and 41 minutes. (NASA/GSFC/SDO) Back to slideshow navigation
  14. Greetings from Robonaut

    This fisheye-lens image, provided by NASA on March 13, shows the Robonaut 2 humanoid robot during a system checkout in the Destiny laboratory of the International Space Station. Teams on the ground commanded Robonaut through a series of dexterity tests as it spelled out "Hello World" in sign language. (NASA via AFP - Getty Images) Back to slideshow navigation
  15. Big and small moons

    Ice-covered Enceladus, a 300-mile-wide Saturnian moon, is dwarfed by 3,200-mile-wide Titan as well as the giant planet's rings in this March 12 picture from the Cassini orbiter. Titan, Saturn's largest moon, is covered by a brownish hydrocarbon-rich haze. (NASA/JPL/SSI/J. Major) Back to slideshow navigation
  16. Fruits ... in ... space!

    Dutch astronaut Andre Kuipers clowns around with some zero-gravity fruit in the International Space Station's Unity node on Feb. 3. (NASA) Back to slideshow navigation
  17. Ghostly nebula

    Wispy tendrils of hot dust and gas are aglow in this ultraviolet image of the Cygnus Loop Nebula, taken by NASA's Galaxy Evolution Explorer and released March 22. The nebula, which lies about 1,500 light-years from Earth, is a supernova remnant left over from a massive stellar explosion that occurred 5,000 to 8,000 years earlier. The Cygnus Loop extends more than three times the size of the full moon in the night sky, and is tucked next to one of the wings of the "swan" in the constellation of Cygnus. (NASA/JPL-Caltech / AFP - Getty Images) Back to slideshow navigation
  18. Mercury in perspective

    This color-coded perspective view shows elevations in the ancient volcanic plains that lie the northern high latitudes of Mercury, as revealed by NASA's Messenger spacecraft. Purple colors are low and white is high, spanning a vertical range of about 1.4 miles (2.3 kilometers). (NASA / JHUAPL / CIW-DTM / GSFC) Back to slideshow navigation
  19. Stirring sight

    After a nearly ice-free winter, Lake Erie was filled with swirls of suspended sediment and algae on March 21. This view from NASA's Terra satellite shows swirls of sediment-rich water in the lake. As the shallowest of the Great Lakes, Erie’s bottom can be stirred up by strong spring winds and the currents they generate. (Jeff Schmaltz / NASA) Back to slideshow navigation
  20. Dust devil caught on camera

    A towering dust devil casts a serpentine shadow on the Martian surface in this image, acquired by the HiRISE camera on NASA's Mars Reconnaissance Orbiter and released on March 7. Such whirlwinds often spin through the Martian landscape - but they're not often caught on camera. (NASA/JPL-Caltech/Univ. of Arizona) Back to slideshow navigation
  21. Dubai's lights at night

    The city lights of Dubai sparkle at night in this photograph taken from the International Space Station on Feb. 22. Dubai is a popular photographic target for the space station's astronauts because of the artificial archipelagos that are located just offshore in the Persian Gulf. The palm-tree-shaped cluster of lights at bottom right is the Palm Jumeira complex, which is still under development. Isolated areas of blurred city lights are due to patchy clouds. (NASA via AP) Back to slideshow navigation
  22. Celestial lanterns

    Two of the brightest planets in the night sky went through a series of conjunctions during late February and March. Jupiter is on the left and Venus is on the right in this picture, taken by Marek Nikodem of Szubin, Poland, at nightfall on March 12. "They are like two lanterns illuminating the darkness," Nikodem told SpaceWeather.com. "It's a wonderful sight." (Marek Nikodem) Back to slideshow navigation
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments