Archive for the ‘Exosolar planets’ Tag

Alien Sunsets   33 comments

Watching the sunset on another world 150 light years from Earth….

What would it look like?

Osiris

HD 209458 b (Osiris) is a large exoplanet or extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earth’s solar system. First discovered on November 5, 1999 during “Spectroscopic studies.”

Osiris_HD 209458bOsiris

Osiris is a 7th magnitude world, visible from Earth with good binoculars or a decent telescope. Osiris (HD209458b), 150 Ly from Earth orbits very closely to its sun. Measured by the Spitzer Infrared Space Telescope on March 23. 2005 it had an atmospheric temperature of around 1,000 degrees Celsius (1,800 degrees Fahrenheit) it’s year lasts just 3.5 Earth days long. Very bad for the aging process!

Osiris Firsts:

First PrizeHD 209458 b was the first transiting extrasolar planet discovered:

  • Known to have an atmosphere
  • Observed to have an evaporating hydrogen atmosphere
  • Found to have an atmosphere containing oxygen and carbon
  • One of the first two extrasolar planets to be directly spectroscopically observed
  • The first extrasolar planet found to have water vapour in its atmosphere. (April 2007)

(Sunset On HD 189733 – Osiris)

Sunset on HD209458b (reconstructed from the HST/STIS transmission spectrum): Image: Frederic Pont of the University of Exeter: based on data form a camera on-board the Hubble Space Telescope)

Osiris doesn’t actually have as surface on which to sit peacefully watching an alien sunset but for the purposes of this post we will pretend it does. What it does have however is an atmosphere, which when passed through by the light from its star (sun) – it does this every so often when Osiris passes between Earth and its own sun (transits)– allows the scientific types here on sunny Earth to figure out in a scientific way mostly beyond the understanding of the average Earthling, exactly which colours its sun would set in, should Osiris have a surface – as already stated it doesn’t but… and we were spending a happily romantic evening sitting on the (make-believe) surface.

I said it HASN’T got one!!! So don’t try it!! It won’t be any good for you!!

In the image to the right Osiris’s sunset can be seen as it would appear if having travelled at light speed to reach it, you were floating 6,200 miles/10,000 km above the planetary surface – preferably not in a deckchair unless you’re wearing a heavy duty space suit 😉 a space station would do nicely.

Floating 6,200 miles above the planetary surface...The Osirisian sun- HD 209458– it’s star, is, much like Earth’s Sun, white – yes I know…The Sun is yellow…but if there was no atmosphere it would look white – not that we would see it because without an atmosphere life on Earth would have survived for approx. 20 seconds before exploding into instant extinction.

An alien sunset on Osiris really does look alien – unlike Earth’s. Osiris’s atmosphere consists of sodium which when starlight (sunlight) zips through it, absorbs the red light. (think prisms and colours of rainbows when white light is split) This results in the remaining starlight appearing blue. It makes perfectly good sense if you were paying attention in your school science lessons. If you weren’t then it’s your own fault and you should be thoroughly ashamed of yourself!!

As back home on Earth the blue light from the star is scattered (“Rayleigh scattering,” a mechanism also responsible for the Earth’s sky being blue) creating a progressive change through the blue end of the spectrum through to a pretty green and later a deep, dark shade of green as its star dips further beneath the horizon.

The more sensible approach to watching the Osirian sunset...In such colours you should be able to get a good view of Osiris’s sun without going instantly blind in which case you will notice it looks oddly flat around the southern half. The same effect occurs when we watch the sun setting from Earth. This is the consequence of diffraction (light bending) and nothing to worry about..

Osiris, Eygptian god of the Underworld_Credit Jeff DahlWhilst you are relaxing in the Osirisian sunset you can reflect on the little snippet of mythology attached to it’s title… Osiris was an Egyptian god, usually identified as the god of the afterlife, the underworld and the dead. He was classically depicted as a green-skinned man with a pharaoh’s beard, partially mummy-wrapped at the legs, wearing a distinctive crown with two large ostrich feathers at either side, and holding a symbolic crook and flail. His green skin is symbolic of new birth. This image is based on New Kingdom tomb paintings.

    

      AND FOR COMPARISION PURPOSES, THE SUNSET ON HD 189733 b

    Sunset on HD 189733 bSunset on HD 189733 b looks like an especially awesome Earth sunset when the sky is very clear and there is only a small amount of dust in the atmosphere. HD 189733 b is much closer to its star (sun) than Earth is to our Sun so its star looks considerably bigger 25 times larger than Earth’s sun when viewed at sunset compared.

Soaking up the atmosphere on HD 189733b

HD 189733 b’s sun is orange and nowhere near as hot as Earth’s Sun and consequently is coloured orange as oppose to the white of our Sun. Instead of undergoing a gradual change of colour as it sets, this alien sun transforms straight from its original orange colour to deepest red in the thick layers of the lower atmosphere.

Jupiter and HD 189733 b size comparison

HD 189733b discovered in 2005 is an extrasolar planet of similar size to Jupiter. It orbits a star (it’s sun) in a binary system called HD 189733 in the constellation of Vulpecula in two Earth days. The aging process on this world would be terribly fast in our terms and those wrinkles would appear in a frighteningly super-smart short time!! The star system itself one of the closest planet-star systems known making it extremely hot. It is located near the Dumbell Nebula, approximately 62 light years from Earth and is known as a “Hot Jupiter.”

HD 189733 and M27, the Dumbbell Nebula. Credit: Daniel Jaroschik

HD 189733b shares many similar characteristics as HD 209458b (a.k.a. “Osiris) Although HD 189733b’s atmosphere isn’t thought to be evaporating like Osiris’, atmospheric gases extend far beyond it and out into space. This is significant in that starlight can also pass through meaning that scientists have been able to figure out that the atmosphere contains water and methane resulting in the probability that HD 189733b may have a blue hue, reminiscent of Uranus.

The atmosphere also contains iron, silicate and aluminium oxide particles. These would seem to collect in HD 189733b’s upper atmosphere, forming a thin, hazy, reflective cloud in the exosphere. This leads to the natural conclusion that the weather on HD 189733b is hot and cloudy.

Thanks to the Spitzer telescope it was discovered in February 2007 for the first time that the atmosphere of exoplanet HD 209458b (Osiris) is relatively dry, thick and dusty. Osiris even contains grains of sand (silicates).

Exoplanet

Although it is not suitable for the existence of alien life it is an exciting step on the road to discovery of such worlds.

Sources:

PhysOrg.com

Prof. Frédéric Pont

ExoClimes.com

Kelper Mission Discovers Twin Earth! (Updated 28th April 2012)   31 comments

 

Gliese 667C – Kelper Mission Discovers Twin Earth!

Billions of potentially habitable alien planets in the Milky Way Smile

Double sunset from Gliese 667C

(Alien Landscape: Artists impression of sunset scene from the Super Earth orbiting the star Gliese 667C (GJ 667C) which is part of the triple star system. The two more distant stars Gliese 667A and Gliese 667B appear in the sky to the right of the image. Astronomers estimate there of tens of billions of small, rocky habitable worlds, in the Milky Way orbiting faint red dwarf stars within their ‘habitable zones,’ where surface water could support life, and dozens within 30 Light Years of Earth. Image Credit: L.Calgada/ESO)

“This was expected to be a rather unlikely star to host planets. Yet there they are very nearby, metal-poor examples of the most common type of star in our galaxy. The detection of this planet and so nearby, and this soon implies that our galaxy must be teeming with billions of potentially habitable rocky planets.” ~ Steven Vogt

Super-Earth Gliese 667C (GJ 667C)

GJ 667C is an M class red dwarf star in a triple star system. The alien ‘super-Earth’ is situated about 22 Light Years away where it is orbiting it’s red dwarf host star in a period of 28 days, and is about 4.5 times larger than Earth. It is temperate enough to allow liquid water to exist on its surface. It is accompanied by orange K class dwarf stars GJ 667A and B.

clip_image004

GJ 667C receives 90% of light received by Earth, most of which is infra-red, so a higher percentage of incoming energy is absorbed by the planet.

Well worth checking out! Though given the distance it is not likely to be in our lifetime, unless warp speed becomes a reality anytime soon!

“This planet is the best candidate to support liquid water and perhaps life as we know it…”

~ Guillem Anglada-Escude

Artists impression of Super-Earth

About 80% of the Milky Way (160 billion) stars are red dwarfs so it is likely that there are around 65 billion stars with habitable Super Earth’s in our galaxy. About 100 lie within 10 parsecs (32.6 Light Years) of Earth.

“Because red dwarfs are so common – there are about 160 million of them in the Milky Way – this leads us to the astonishing result that there are tens of billions of these planets in our galaxy alone.”~ Dr Xavier Bonfils from Grenoble University in France, who led the international team.

Star spectral classes comparison

THE STUDY – Between February 2008 and April 2009 researchers at the European Southern Observatory, La Sill Observatory in Chile, studied 102 Class M (Red Dwarf) stars situated at a distance of less than 32.6 Light Years away. New planets, new life?New planets are discovered by detecting the subtle wobbles that occur when the planets are orbiting their star. 41% of them are orbiting their stars inside the habitable zone, where they could potentially support life.

GJ 667C was discovered by Astronomers from UC Santa Cruz, Steven Vogt and Eugenio Rivera, led by Guillem Anglada-Escude and Paul Butler of Carniegie Institution for Science.

The HARPS high-precision ‘Planet Hunter’ device works with the 3.6m telescope at the Silla Observatory in Chile to bring us these results.

When the information obtained via a telescope was input into the instruments nine super-Earth planets were detected by astronomers. These included Gliese (GJ) 581 and Gliese(GJ) 667C both of which are within the habitable zones of their stars.

clip_image012However, it should also be remembered that Red dwarf stars are not as super-hot as our star – The Sun. Consequently the super-Earth planets that orbit them must Flares from alien sundo so at a considerably closer range in order to obtain the necessary heat. With their habitable zones in such close proximity to their stars compared to the distance of Earth to the Sun there is a danger that the potential for life could be inhibited by the dangerous X-ray and ultraviolet flares emitted by their stars, which could successfully frazzle any life!

NEWS UPDATE: REPORTS CONFIRM EXISTENCE OF HABITABLE EXO-PLANET! (28TH APRIL 2012)

After re-evaluating information collected back in February, scientists reportedly confirmed on Friday that they had indeed discovered a planet outside of our solar system that is capable of supporting life.

On Friday, the Telegraph published a report confirming the findings.

“Re-analyzing data from the European Southern Observatory, the astronomers found Gliese 667Cc is a solid planet with roughly four and a half times the mass of Earth,” they said, adding that astronomers from the University of Göttingen and the University of California “have calculated the planet receives ten per cent less light from its red dwarf star than the Earth gets from the Sun.”

“It’s the Holy Grail of exo-planet research to find a planet orbiting around a star at the right distance so it’s not too close where it would lose all its water and not too far where it would freeze,” University of California astronomer Steven Vogt said, according to the UK publication. “It’s right there in the habitable zone — there’s no question or discussion about it. It is not on the edge. It is right in there.”

(Source: redOrbit)

 

NASA Discover Alien Planet Earth Twin –Kelper-22b   46 comments

 

Alien Earth-Twin: Planet Kelper-22b

NASA Kelper: Planet Hunting Spacecraft

Kepler 22b, the new alien planet discovered by NASA’s Kepler space telescope, which NASA scientists say embraces the most hopeful possibility to date for potential future human habitation. Scientists also believe there is a tantalising option for the presence of continents, oceans and even alien life forms living on its surface. Kepler-22b is the first of many such planets that it is hoped will be discovered by the Kepler space telescope.

The Kepler Mission is a NASA Discovery Program for detecting potentially life-supporting planets-. those where liquid water might exist on the surface of those around other stars in the habitable zone. Terrestrial planets. (i.e. those one half to twice the size of the Earth)

Kelper Telescope

NASA’s Kelper planet-hunting spacecraft, a Space Observatory, that has been orbiting Earth since it was launched in March 2009 is the most powerful telescope in space. It needs a large field in order to observe the necessary large number of stars.

Beginning in the Star Fields

Kelper will be searching constantly in the Cygnus star field, staring unblinkingly at around 155,000 stars every half hour, looking for tiny drops in brightness that betray the presence of planets, for the duration of it’s 3.5 years+ mission. Cygnus is ideal as it lacks in bright stars that would hamper the instruments and it contains many stars similar to our Sun

image

Kepler’s targetd star field in nearby region of the Milky Way. Credit: NASA

The star around which Kepler 22b orbits in the region of the constellations of Lyra and Cygnus, is slightly smaller than our Sun and about 25% less bright. The alien planet was discovered after making a "transit" across the front of its parent star – when a planet crosses in front of its star (Sun) it blocks a small fraction of the light from that star.

                               Cygnus Star field                                       Kelper's Transit Method

Image 1. Kepler’s targeted star field. Credit: Carter Roberts of the Eastbay Astronomical Society   \mage 2. Artist’s rendering of Kepler’s Transit Method of Detecting Extrasolar Planets. Credit: SETI Institute

It is these microscopic variations in the star’s brightness that Kelper can detect. These tell the planet size. The time between ‘transits’ indicates the size of the planet’s orbit and estimates the planet’s temperature. These factors determine possibilities for life on the planet.

Alien Planet Kelper-22b

kepler22b-artwork

This artist’s conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star.
CREDIT: NASA/Ames/JPL-Caltech

2.4 times the size of earth Kelper 22b orbits a star similar to, but smaller and cooler than, our own sun. Scientists say it is 15% closer to its own star than Earth is to our Sun and is located at the somewhat daunting distance of 600 light years away from our own Solar System. At 290 days, the duration of a year on Kepler-22b is not far off our own and the planet’s surface temperature is an agreeable 22deg C. (72deg F) (Sign up here if you wish to join Wolfie on a summer holiday) 😉

Its atmosphere is of a nature that could potentially support life and Kepler-22b is the first “Earth twin” known that is situated in the ‘habitable zone’ of another Sun-like star. This allows for temperatures fitting to the existence of liquid surface water throughout its orbit. I.e. Kelper- 22b could have Earth-like continents and oceans…and where there is liquid water there is also a strong possibility of life. It is even possible, according to scientists that Kelper-22b is in fact already inhabited!

However scientists have yet to figure out whether Kepler-22b is of a primarily rock, liquid or gas composition. A rocky surface would be the best ideal for life. However, a certain Professor Abel Mendez of the Planetary Habitability Laboratory has pessimistically suggested that the chances are that the new and alien planet is likely to be too big to be a habitable world… well there’s always one!

To date the Kepler space telescope has discovered a grand total of 48 planets in the habitable zone of their own solar systems. (The “Goldilocks zone”) Kepler-22b is just the first alien world within such a zone to have been confirmed by other telescopes observations.

NASA announced the discovery of Kepler-22b on Dec. 5 2011.

 Planets and orbits to scale

Comparison chart of our own solar system and  Kepler-22, a star system containing the first "habitable zone" planet discovered.

"This discovery supports the growing belief that we live in a universe crowded with life," ~ Dr Alan Boss, from the Carnegie Institution for Science in Washington DC, helped identify the planet from data collected by the Kepler space telescope.

"This is a major milestone on the road to finding Earth’s twin," ~ Douglas Hudgins, a member of the Kepler telescope team.

“Fortune smiled upon us with the detection of this planet," ~ William Borucki, who led the team that discovered Kepler-22b.