Planet Xena has a Gabrielle

Lord Zentei · Post by **Lord Zentei** » 2005-10-01 11:39pm

CNN wrote:'Planet Xena' has a sidekick: Gabrielle

Scientists find moon circling 'planet'

Saturday, October 1, 2005; Posted: 11:12 p.m. EDT (03:12 GMT)

LOS ANGELES, California (AP) -- The astronomers who claim to have discovered the 10th planet in the Earth's solar system have made another intriguing announcement: it has a moon.

While observing the new, so-called planet from Hawaii last month, a team of astronomers led by Michael Brown of the California Institute of Technology spotted a faint object trailing next to it. Because it was moving, astronomers ruled it was a moon and not a background star, which is stationary.

The moon discovery is important because it can help scientists determine the new planet's mass. In July, Brown announced the discovery of an icy, rocky object larger than Pluto in the Kuiper Belt, a disc of icy bodies beyond Neptune. Brown labeled the object a planet and nicknamed it Xena after the lead character in the former TV series "Xena: Warrior Princess."

By determining the moon's distance and orbit around Xena, scientists can calculate how heavy Xena is. For example, the faster a moon goes around a planet, the more massive a planet is.

But the newly discovered moon, nicknamed Gabrielle after Xena's faithful traveling sidekick in the TV series, likely will not quell the debate over what exactly is a planet and whether Pluto should keep its status. The problem is there is no official definition for a planet and setting standards like size limits potentially invites other objects to take the "planet" label.

Possessing a moon is not a criteria of planethood since Mercury and Venus are moonless planets. Brown said he expected to find a moon orbiting Xena because many Kuiper Belt objects are paired with moons.

The moon is about 155 miles wide and 60 times fainter than Xena, the farthest-known object in the solar system. It is currently 9 billion miles away from the sun, or about three times Pluto's current distance from the sun.

Scientists believe Xena's moon was formed when Kuiper Belt objects collided with one another. The Earth's moon formed in a similar way when Earth crashed into an object the size of Mars.

The moon was first spotted by a 10-meter telescope at the W.M. Keck Observatory in Hawaii on September 10. Scientists expect to learn more about the moon's composition during further observations with the Hubble Space Telescope in November.

Brown planned to submit a paper describing the moon discovery to the Astrophysical Journal next week.

The International Astronomical Union, a group of scientists responsible for naming planets, is deciding on formal names for Xena and Gabrielle.

Solauren · Post by **Solauren** » 2005-10-01 11:44pm

I vote if they formally name them Xena and Gabrielle, we build a Death Star and blow them out of the universe.

If you're gonna name a '10th planet' anything, please not after a fantasy-drama show starting a C (or B at best) list actress

Lord Zentei · Post by **Lord Zentei** » 2005-10-01 11:48pm

Solauren wrote:I vote if they formally name them Xena and Gabrielle, we build a Death Star and blow them out of the universe.

If you're gonna name a '10th planet' anything, please not after a fantasy-drama show starting a C (or B at best) list actress

It's only temporary until the IAU decides on a formal name. Astronomers are geeks, what did you expect, Roman mythology?

Anyway, here is SpaceRef's take on it:

SpaceRef wrote:Tenth Planet Has a Moon

PASADENA, Calif. --The newly discovered 10th planet, 2003 UB313, is looking more and more like one of the solar system's major players. It has the heft of a real planet (latest estimates put it at about 20 percent larger than Pluto), a catchy code name (Xena, after the TV warrior princess), and a Guinness Book-ish record of its own (at about 97 astronomical units-or 9 billion miles from the sun-it is the solar system's farthest detected object). And, astronomers from the California Institute of Technology and their colleagues have now discovered, it has a moon.

The moon, 100 times fainter than Xena and orbiting the planet once every couple of weeks, was spotted on September 10, 2005, with the 10-meter Keck II telescope at the W.M. Keck Observatory in Hawaii by Michael E. Brown, professor of planetary astronomy, and his colleagues at Caltech, the Keck Observatory, Yale University, and the Gemini Observatory in Hawaii. A paper about the discovery was submitted on October 3 to Astrophysical Journal Letters.

"Since the day we discovered Xena, the big question has been whether or not it has a moon," says Brown. "Having a moon is just inherently cool-and it is something that most self-respecting planets have, so it is good to see that this one does too."

Brown estimates that the moon, nicknamed "Gabrielle"-after the fictional Xena's fictional sidekick-is at least one-tenth of the size of Xena, which is thought to be about 2700 km in diameter (Pluto is 2274 km), and may be around 250 km across.

To know Gabrielle's size more precisely, the researchers need to know the moon's composition, which has not yet been determined. Most objects in the Kuiper Belt, the massive swath of miniplanets that stretches from beyond Neptune out into the distant fringes of the solar system, are about half rock and half water ice. Since a half-rock, half-ice surface reflects a fairly predictable amount of sunlight, a general estimate of the size of an object with that composition can be made. Very icy objects, however, reflect a lot more light, and so will appear brighter-and thus bigger-than similarly sized rocky objects.

Further observations of the moon with the Hubble Space Telescope, planned for November and December, will allow Brown and his colleagues to pin down Gabrielle's exact orbit around Xena. With that data, they will be able to calculate Xena's mass, using a formula first devised some 300 years ago by Isaac Newton.

"A combination of the distance of the moon from the planet and the speed it goes around the planet tells you very precisely what the mass of the planet is," explains Brown. "If the planet is very massive, the moon will go around very fast; if it is less massive, the moon will travel more slowly. It is the only way we could ever measure the mass of Xena-because it has a moon."

The researchers discovered Gabrielle using Keck II's recently commissioned Laser Guide Star Adaptive Optics system. Adaptive optics is a technique that removes the blurring of atmospheric turbulence, creating images as sharp as would be obtained from space-based telescopes. The new laser guide star system allows researchers to create an artificial "star" by bouncing a laser beam off a layer of the atmosphere about 75 miles above the ground. Bright stars located near the object of interest are used as the reference point for the adaptive optics corrections. Since no bright stars are naturally found near Xena, adaptive optics imaging would have been impossible without the laser system.

"With Laser Guide Star Adaptive Optics, observers not only get more resolution, but the light from distant objects is concentrated over a much smaller area of the sky, making faint detections possible," says Marcos van Dam, adaptive optics scientist at the W.M. Keck Observatory, and second author on the new paper.

The new system also allowed Brown and his colleagues to observe a small moon in January around 2003 EL61, code-named "Santa," another large new Kuiper Belt object. No moon was spotted around 2005 FY9-or "Easterbunny"-the third of the three big Kuiper Belt objects recently discovered by Brown and his colleagues using the 48-inch Samuel Oschin Telescope at Palomar Observatory. But the presence of moons around three of the Kuiper Belt's four largest objects-Xena, Santa, and Pluto-challenges conventional ideas about how worlds in this region of the solar system acquire satellites.

Previously, researchers believed that Kuiper Belt objects obtained moons through a process called gravitational capture, in which two formerly separate objects moved too close to one another and become entrapped in each other's gravitational embrace. This was thought to be true of the Kuiper Belt's small denizens-but not, however, of Pluto. Pluto's massive, closely orbiting moon, Charon, broke off the planet billions of years ago, after it was smashed by another Kuiper Belt object. Xena's and Santa's moons appear best explained by a similar origin.

"Pluto once seemed a unique oddball at the fringe of the solar system," Brown says. "But we now see that Xena, Pluto, and the others are part of a diverse family of large objects with similar characteristics, histories, and even moons, which together will teach us much more about the solar system than any single oddball ever would."

For more information on the discovery and on Xena, visit www.gps.caltech.edu/~mbrown/planetlila

mr friendly guy · Post by **mr friendly guy** » 2005-10-02 12:49am

What about naming the 10th planet Mondas. Cookies for those who get the reference.

CaptainChewbacca · Post by **CaptainChewbacca** » 2005-10-02 03:09am

mr friendly guy wrote:What about naming the 10th planet Mondas. Cookies for those who get the reference.

Cybermen planet in Dr. Who? It was the 10th planet over there, I think. That's why it came to mind just now.

speaker-to-trolls · Post by **speaker-to-trolls** » 2005-10-02 04:26am

I could have sworn the 'tenth planet' was called Sedna (Inuit sea goddess), or am I thinking of a different tenth planet?

Grandmaster Jogurt · Post by **Grandmaster Jogurt** » 2005-10-02 05:05am

speaker-to-trolls wrote:I could have sworn the 'tenth planet' was called Sedna (Inuit sea goddess), or am I thinking of a different tenth planet?

That's a different body. Of the Kuiper Belt Objects, the only ones that have been named so far (AFAIK) have been Pluto, Charon, Quaor, and Sedna. Only the first has ever been seriously considered to be a planet.

Post by **Darth Wong** » 2005-10-02 05:14am

Looks like Xena: Warrior Princess just took cosmological geek bragging rights away from Star Trek and its fans' 20 years of wanking over having a non-functional prototype shuttle named "Enterprise".

Superman · Post by **Superman** » 2005-10-02 05:44am

Darth Wong wrote:Looks like Xena: Warrior Princess just took cosmological geek bragging rights away from Star Trek and its fans' 20 years of wanking over having a non-functional prototype shuttle named "Enterprise".

Ha! That's great. But you have to admit, "Xena" is one of the worst names they could have used. So does this mean that it's going to get an official name later?

Not Brian

mr friendly guy · Post by **mr friendly guy** » 2005-10-02 05:58am

CaptainChewbacca wrote:
mr friendly guy wrote:What about naming the 10th planet Mondas. Cookies for those who get the reference.
Cybermen planet in Dr. Who? It was the 10th planet over there, I think. That's why it came to mind just now.

You are correct. Mondas was the 10th planet in the solar system in Dr Who mythos, which drifted away. The Cybermen return to the solar system in the episode the 10th planet, which was their first appearance.

Tsyroc · Post by **Tsyroc** » 2005-10-02 11:15am

Darth Wong wrote:Looks like Xena: Warrior Princess just took cosmological geek bragging rights away from Star Trek and its fans' 20 years of wanking over having a non-functional prototype shuttle named "Enterprise".

Wasn't the reason "Vulcan" was a planet on Star Trek because at one time there was a theory that there was another planet in our solar system that was closer to the sun than Mercury?

At least I thought I remember reading about something along those lines at the time.

So if this planet is out past Pluto they could call it Proserpine (Persephone) but I don't know what to call the moon since naming it after her mother doesn't seem right.

Another possibility would be Cupid with the moon being Psyche.

HemlockGrey · Post by **HemlockGrey** » 2005-10-02 12:14pm

How about Planet Bob? (cookie for the reference)

If we're going with the mythology theme, I'd recommend Priapus...because every solar system should have a planet named after an impotent dwarf-god with an enormous penis.

Vanas · Post by **Vanas** » 2005-10-02 12:34pm

Hmm. If they want to name this duo Xena and Gabrielle, I dread to think what's next. I look forward to the discovery of planet Batman.

HemlockGrey: You can't call a planet 'Bob'!
Titan AE, by any chance?

StarshipTitanic · Post by **StarshipTitanic** » 2005-10-02 12:48pm

HemlockGrey wrote:How about Planet Bob? (cookie for the reference)

That movie sucked, and you suck for bringing it up.

Lord Zentei · Post by **Lord Zentei** » 2005-10-02 02:02pm

Darth Wong wrote:Looks like Xena: Warrior Princess just took cosmological geek bragging rights away from Star Trek and its fans' 20 years of wanking over having a non-functional prototype shuttle named "Enterprise".

When a gas giant planet was discovered orbiting Epsilon Eridani it got an unofficial name from Star Trek. "Vulcan", of course. No word on Spock yet, though.

Superman wrote:Ha! That's great. But you have to admit, "Xena" is one of the worst names they could have used. So does this mean that it's going to get an official name later?

Yup, apparently so. The IAU will make up its mind eventually.

Post by **fgalkin** » 2005-10-02 02:55pm

Lord Zentei wrote:
Solauren wrote:I vote if they formally name them Xena and Gabrielle, we build a Death Star and blow them out of the universe.

If you're gonna name a '10th planet' anything, please not after a fantasy-drama show starting a C (or B at best) list actress
It's only temporary until the IAU decides on a formal name. Astronomers are geeks, what did you expect, Roman mythology?

Exactly. Astronomers are geeks not Xena fanboys. I expected a quality sci-fi reference, but apparently, I underestimated the power of b00bies.

Have a very nice day.
-fgalkin

Grandmaster Jogurt · Post by **Grandmaster Jogurt** » 2005-10-02 06:33pm

Tsyroc wrote:
Darth Wong wrote:Looks like Xena: Warrior Princess just took cosmological geek bragging rights away from Star Trek and its fans' 20 years of wanking over having a non-functional prototype shuttle named "Enterprise".
Wasn't the reason "Vulcan" was a planet on Star Trek because at one time there was a theory that there was another planet in our solar system that was closer to the sun than Mercury?

I don't know about its effect on Star Trek nomenclature, but there was indeed thoughts of an intra-Mercurial planet named Vulcan. The idea was dropped when Einstein's general theory of relativity was published, which explained the deviations in Mercury's orbit.

So if this planet is out past Pluto they could call it Proserpine (Persephone) but I don't know what to call the moon since naming it after her mother doesn't seem right.

Not only that, but the name Ceres is already taken by a rather important object, that being the first-discovered and largest of all asteroids.

Xess · Post by **Xess** » 2005-10-03 12:42am

StarshipTitanic wrote:That movie sucked, and you suck for bringing it up.

Bah! That movie was great and you have no taste.

Anywho, I say we name them Bill and Ted so they can have an excellent adventrue.

Zed Snardbody · Post by **Zed Snardbody** » 2005-10-04 12:26pm

StarshipTitanic wrote:
HemlockGrey wrote:How about Planet Bob? (cookie for the reference)
That movie sucked, and you suck for bringing it up.

Doug man! Doug! With quail man!

drachefly · Post by **drachefly** » 2005-10-04 02:11pm

What about 'Rupert'? That would have worked much better as a temporary name.

HemlockGrey · Post by **HemlockGrey** » 2005-10-04 02:20pm

That movie sucked, and you suck for bringing it up.

No way man, Titan AE was a good movie.

Noble Ire · Post by **Noble Ire** » 2005-10-04 07:33pm

HemlockGrey wrote:
That movie sucked, and you suck for bringing it up.
No way man, Titan AE was a good movie.

One of the better American-made (IIRC) cartoon films made in the last decade IMO. Right up there with The Iron Giant.