Astronomers to Detail Aspects of Planetoid

[Nick]

Hi Andromache,

Welcome to the Astral Pulse! [] Thanks for the astronomical post too. There are so many aspects to the far reaching universe yet to be learned, that's for sure.


Very best,

[Andromache]

'New planet' may have a moon

The distant object that some astronomers think could be the Solar System's 10th planet may have a moon.
The new planetary candidate, which has been named Sedna, rotates more slowly on itself than expected, suggesting it may have a satellite orbiting it.

One of the scientists who found Sedna has been giving further details of its discovery at a news conference.

Observations show it measures less than 1,700km (about 1,000 miles) in diameter, which is smaller than Pluto.

"We think that there's evidence there is a satellite around Sedna," said Dr Mike Brown, of the California Institute of Technology, US, and leader of the research team that found the body.

"We're hoping in the very near future to get some observations from the Hubble Space Telescope that should put that question to rest."

It was first seen on 14 November 2003 with the 48-inch Samuel Oschin Telescope at California's Mount Palomar Observatory. Astronomers from the California Institute of Technology, Yale Observatory and the Gemini Observatory were involved in the discovery.

Sedna, which is named after the Inuit goddess of the ocean, is both very red and very shiny.

This combination is extremely unusual in the Solar System and has baffled scientists trying to determine what it is made of.

Further than Pluto

Sedna, or 2003 VB12, as it was originally designated, is the most distant object yet found orbiting our Sun. It is three times further away than Pluto (average distance to the Sun is 5.9 billion km or 3.6 billion miles).

"The Sun appears so small from that distance that you could completely block it out with the head of a pin," said Dr Brown.

He added that, in his view, the object's apparently small size suggested it should not be classified as a true planet.
Dr Brown suggested the "planetoid" was about half-rock and half-ice mixed together, but further work was needed to verify this.

Follow-up studies by the Tanagra Observatory have measured the thermal radiation coming from Sedna to determine how hot it is, and help provide some estimate of its size.

Researchers believe that Sedna's surface temperature is about -240 degrees Celsius (-400 degrees Fahrenheit).

The object is usually even colder, because it approaches the Sun only briefly during its 10,500-year solar orbit.

At its most distant, Sedna is 130 billion km (84 billion miles) from the Sun, which is 900 times Earth's solar distance (149 million km or 93 million miles).

Small worlds

Although Sedna could be a so-called Kuiper Belt object, its discoverers are unsure if it is as they consider it to be unlike any other object yet found.


KUIPER BELT OBJECTS
Icy planetary bodies that orbit beyond Neptune in the distant region of the Solar System
More than 400 such objects are currently known
They are believed to be remnants of the formation of the Solar System and among the most primitive objects available for study
It could be the first detection of the long-hypothesized "Oort cloud", a faraway repository of small icy bodies that supplies the comets that streak by Earth.
In recent years, astronomical work has thrown up several big objects in the outer Solar System. Quaoar, found in 2002, is about 1,200km (745 miles) across. Ixion, discovered in 2001, is 1,065 km (660 miles) wide. Varuna, detected in 2000, has a diameter of approximately 900 km (560 miles).

And only in February this year, scientists picked up the object 2004 DW, which is though to be 1,800km (1,120 miles) across.

The new discovery will reignite the debate about what constitutes a planet.

One group of astronomers believe that Pluto is not a true planet but merely one of the largest of a vast number of minor objects in the outer Solar System.
The alternative standpoint is that Pluto is a planet and those who believe that will have to classify Sedna as the 10th planet.


Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/3514594.stmPublished: 2004/03/15 20:07:44 GMT

© BBC MMIV

[Kazbadan]

DO you have any news on the Planet X? Not the mytical one but the real one, wich the astronomers said that there are 50% hypothesis that there is indeed a big tenth (not sedna or quaoar) planet.

Such planet would have 10 times the mass of the earth.


Do you know any thing new about that?

thanks

[James S]

One of the interesting things thats being looked at now is the correlation between Sedna's orbit and that of Pluto.

It's long been thought that Pluto was not originally an independent planet, but a moon, possibly of Neptune. The apperance of Sedna has prompted astronomers to backtrack the paths of Neptune, Pluto and Sedna to see if there was a point where Sedna's gravity influence may have been enough to pull Pluto and Charon out of Neptune's orbit.

One of the ideas behind this is the thought that Pluto is almost too small to technicall be classed as a planet, and Charon, Pluto's moon, is close to being the same size as Pluto, making them almost binary planetoids rather than planet and satellite. If they were indeed once satellites of Neptune, this would make sense.

Regards,
James.

[Andromache]

Astronomers to Detail Aspects of Sedna

Astronomers to Detail Aspects of Planetoid That Is the Most Distant Object in Solar System

The Associated Press

LOS ANGELES March 15 — It is a frozen world more than 8 billion miles from Earth and believed to be the farthest known object within our solar system.

NASA planned a Monday press conference to offer more details about Sedna, a planetoid between 800 miles and 1,100 miles in diameter, or about three-quarters the size of Pluto.

Named for the Inuit goddess who created the sea creatures of the Arctic, Sedna lies more than three times farther from the sun than Pluto. It was discovered in November.

"The sun appears so small from that distance that you could completely block it out with the head of a pin," said Mike Brown, an astronomer at the California Institute of Technology who led the NASA-funded team that found Sedna.

That makes Sedna the largest object found orbiting the sun since the discovery of Pluto, the ninth planet, in 1930. It trumps in size another world, called Quaoar, discovered by the same team in 2002.

Brown and his colleagues estimate the temperature on Sedna never rises above 400 degrees below zero Fahrenheit, making it the coldest known body in the solar system.

Sedna follows a highly elliptical path around the sun, a circuit that it takes 10,500 years to complete. Its orbit loops out as far as 84 billion miles from the sun, or 900 times the distance between the Earth and our star.

Brown and Chad Trujillo, of the Gemini Observatory in Hawaii, and David Rabinowitz, of Yale University, discovered Sedna on Nov. 14, 2003, using a 48-inch telescope at Caltech's Palomar Observatory east of San Diego.

Within days, other astronomers around the world trained their telescopes, including the recently launched Spitzer Space Telescope, on the object.

The team also have indirect evidence a tiny moon may trail Sedna, which is redder than all other known solar system bodies except Mars.