Orion (constellation)

Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It was named after Orion, a hunter in Greek mythology. Its brightest stars are Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), a blue-white and a red supergiant, respectively.

Orion’s seven brightest stars form a distinctive hourglass-shaped asterism, or pattern, in the night sky. Four stars—Rigel, Betelgeuse, Bellatrix and Saiph—form a large roughly rectangular shape, in the centre of which lie the three stars of Orion’s Belt—Alnitak, Alnilam and Mintaka.

Orion’s Belt or The Belt of Orion is an asterism within the constellation. It consists of the three bright stars Zeta (Alnitak), Epsilon (Alnilam), and Delta (Mintaka). Alnitak is around 800 light years away from earth and is 100,000 times more luminous than the Sun; much of its radiation is in the ultraviolet range, which the human eye cannot see. Alnilam is approximately 1340 light years away from Earth, shines with magnitude 1.70, and with ultraviolet light is 375,000 times more luminous than the Sun. Mintaka is 915 light years away and shines with magnitude 2.21. It is 90,000 times more luminous than the Sun and is a double star: the two orbit each other every 5.73 days.

Around 20 October each year the Orionid meteor shower (Orionids) reaches its peak. Coming from the border with the constellation Gemini as many as 20 meteors per hour can be seen. The shower’s parent body is Halley’s Comet.

M78 (NGC 2068) is a nebula in Orion. With an overall magnitude of 8.0, it is significantly dimmer than the Great Orion Nebula that lies to its south; however, it is at approximately the same distance, at 1600 light-years from Earth. It can easily be mistaken for a comet in the eyepiece of a telescope.

Another fairly bright nebula in Orion is NGC 1999, also close to the Great Orion Nebula. It has an integrated magnitude of 10.5 and is 1500 light-years from Earth. The variable star V380 Orionis is embedded in NGC 1999.

Another famous nebula is IC 434, the Horsehead Nebula, near ζ Orionis. It contains a dark dust cloud whose shape gives the nebula its name.

NGC 2174 is an emission nebula located 6400 light-years from Earth.

Besides these nebulae, surveying Orion with a small telescope will reveal a wealth of interesting deep-sky objects, including M43, M78, as well as multiple stars including Iota Orionis and Sigma Orionis. A larger telescope may reveal objects such as Barnard’s Loop and the Flame Nebula (NGC 2024), as well as fainter and tighter multiple stars and nebulae.

All of these nebulae are part of the larger Orion Molecular Cloud Complex, which is located approximately 1,500 light-years away and is hundreds of light-years across. It is one of the most intense regions of stellar formation visible within our galaxy.

source

image credit: Tunç Tezel, H. Raab, Andrew Walker, Geert Vanhauwaert, Jason Hullinger, ESO, NASA/ESA Hubble

What’s Up for June 2016?

What’s Up for June? Saturn at its best! Plus, good views of Mars, Jupiter and Jupiter’s moons continue from dusk to dawn.

You don’t have to stay up late to see Jupiter, Mars and Saturn this month, because they’re all visible soon after sunset. Jupiter is the brightest of the three, visible in the western sky all evening.

The four Galilean moons are easily visible in binoculars or telescopes. If you think you’re seeing 5 moons on June 10th, you’re not. One of them is a distant star in the constellation Leo.

For telescope viewers, the time near Mars’ closest approach to Earth, May 30th this year, is the best time to try to see the two moons of Mars: Phobos and Deimos. It takes patience, very steady skies and good charts! Mars is still large and bright in early June, but it fades as speedy Earth, in its shorter orbit around the sun, passes it.

Saturn has been close to Mars recently. This month Saturn reaches opposition, when Saturn, Earth and the sun are in a straight line with Earth in the middle, providing the best and closest views of the ringed beauty and several of its moons. You’ll be able to make out cloud bands on Saturn, in delicate shades of cream and butterscotch. They’re fainter than the bands of Jupiter. Through a telescope you’ll see Saturn’s rings tilted about as wide as they get: 26 degrees.

You’ll also have a ring-side view of the Cassini division, discovered by Giovanni Domenico Cassini, namesake of our Cassini spacecraft, orbiting Saturn since 2004 and continuing through September 2017. When you look at Saturn through a telescope, you can’t help but see several of its 4 brightest moons, and maybe more. If you just see one, that’s Titan, 50% larger than our own moon. A telescope can also reveal more moons, like Saturn’s two-colored moon Iapetus. It takes 3 months to orbit Saturn, and it’s fairly easy to see.

There’s a bright comet visible this month, Comet PanSTARRS. It’s best seen from the southern hemisphere, but it’s also visible from the U.S. low in the morning sky. Comet PanSTARRS can be seen through a telescope near the beautiful Helix Nebula on June 4, but it is visible all month.

Watch the full June “What’s Up” video for more: https://youtu.be/M7RtIa9zBYA

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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carlosalberthreis

8 years ago

Falta 1 mês pra sonda Juno chegar em Júpiter. Comecei uma série no canal para explicar a missão. O primeiro vídeo já está no ar - https://youtu.be/qjxJ12IB4MQ

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carlosalberthreis

8 years ago

Juno: Inside the Spacecraft

Our Juno spacecraft was carefully designed to meet the tough challenges in flying a mission to Jupiter: weak sunlight, extreme temperatures and deadly radiation. Lets take a closer look at Juno:

It Rotates!

Roughly the size of an NBA basketball court, Juno is a spinning spacecraft. Cartwheeling through space makes the spacecraft’s pointing extremely stable and easy to control. While in orbit at Jupiter, the spinning spacecraft sweeps the fields of view of its instruments through space once for each rotation. At three rotations per minute, the instruments’ fields of view sweep across Jupiter about 400 times in the two hours it takes to fly from pole to pole.

It Uses the Power of the Sun

Jupiter’s orbit is five times farther from the sun than Earth’s, so the giant planet receives 25 times less sunlight than Earth. Juno will be the first solar-powered spacecraft we’ve designed to operate at such a great distance from the sun. Because of this, the surface area of the solar panels required to generate adequate power is quite large.

Three solar panels extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of about 66 feet. Juno benefits from advances in solar cell design with modern cells that are 50% more efficient and radiation tolerant than silicon cells available for space missions 20 years ago. Luckily, the mission’s power needs are modest, with science instruments requiring full power for only about six out of each 11-day orbit.

It Has a Protective Radiation Vault

Juno will avoid Jupiter’s highest radiation regions by approaching over the north, dropping to an altitude below the planet’s radiation belts, and then exiting over the south. To protect sensitive spacecraft electronics, Juno will carry the first radiation shielded electronics vault, a critical feature for enabling sustained exploration in such a heavy radiation environment.

Juno Science Payload:

Gravity Science and Magnetometers – Will study Jupiter’s deep structure by mapping the planet’s gravity field and magnetic field.

Microwave Radiometer – Will probe Jupiter’s deep atmosphere and measure how much water (and hence oxygen) is there.

JEDI, JADE and Waves – These instruments will work to sample electric fields, plasma waves and particles around Jupiter to determine how the magnetic field is connected to the atmosphere, and especially the auroras (northern and southern lights).

JADE and JEDI

Waves

UVS and JIRAM – Using ultraviolet and infrared cameras, these instruments will take images of the atmosphere and auroras, including chemical fingerprints of the gases present.

UVS

JIRAM

JunoCam – Take spectacular close-up, color images.

Follow our Juno mission on the web, Facebook, Twitter, YouTube and Tumblr.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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carlosalberthreis

2 years ago

🎶 Vimos sua estrela no Oriente

E assim vimos adorar o Rei da gente 🎶

What’s Up - February 2018

What’s Up For February?

This month, in honor of Valentine’s Day, we’ll focus on celestial star pairs and constellation couples.

Let’s look at some celestial pairs!

The constellations Perseus and Andromeda are easy to see high overhead this month.

According to lore, the warrior Perseus spotted a beautiful woman–Andromeda–chained to a seaside rock. After battling a sea serpent, he rescued her.

As a reward, her parents Cepheus and Cassiopeia allowed Perseus to marry Andromeda.

The great hunter Orion fell in love with seven sisters, the Pleiades, and pursued them for a long time. Eventually Zeus turned both Orion and the Pleiades into stars.

Orion is easy to find. Draw an imaginary line through his belt stars to the Pleiades, and watch him chase them across the sky forever.

A pair of star clusters is visible on February nights. The Perseus Double Cluster is high in the sky near Andromeda’s parents Cepheus and Cassiopeia.

Through binoculars you can see dozens of stars in each cluster. Actually, there are more than 300 blue-white supergiant stars in each of the clusters.

There are some colorful star pairs, some visible just by looking up and some requiring a telescope. Gemini’s twins, the brothers Pollux and Castor, are easy to see without aid.

Orion’s westernmost, or right, knee, Rigel, has a faint companion. The companion, Rigel B, is 500 times fainter than the super-giant Rigel and is visible only with a telescope.

Orion’s westernmost belt star, Mintaka, has a pretty companion. You’ll need a telescope.

Finally, the moon pairs up with the Pleiades on the 22nd and with Pollux and Castor on the 26th.

Watch the full What’s Up for February Video:

There are so many sights to see in the sky. To stay informed, subscribe to our What’s Up video series on Facebook.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

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carlosalberthreis

8 years ago

Eu já falei muitas vezes para vocês que os buracos negros podem ser classificados em 3 categorias: os buracos negros supermassivos encontrados no centro de galáxias, os buracos negros de massa estelar e os buracos negros intermediários.

Esses últimos ainda não tiveram sua existência confirmada, mas os astrônomos acreditam que eles devem sim existir.

Esse tipo de buraco negro teria uma massa entre 100 e 10 mil vezes a massa do Sol e a importância além de serem o ele perdido entre os buracos negros estelares e os supermassivos, eles poderiam ser as sementes que dão origem aos buracos negros supermassivos.

Um grupo de astrônomos anunciou na última edição da revista Nature evidências para a existência de um buraco negro de massa intermediária no interior do aglomerado globular 47 Tucanae.

Esse aglomerado tem 12 bilhões de anos de vida e está localizado a cerca de 13 mil anos-luz de distância da Terra, na constelação de Tucano.

Ele contém milhares de estrelas, condensadas numa bola com 120 anos-luz de diâmetro. Além disso ele possui duas dezenas de pulsares que são importantes para essas evidências.

Esse aglomerado já foi examinado na busca por buraco negro, mas o resultado não foi o desejado, porque não no raio-X só é possível identificar os buracos negros supermassivos se alimentando ferozmente. O que não é o caso no interior desse aglomerado.

Mesmo em buracos negros mais calmos como o da nossa galáxia, inferir a sua presença não é algo complicado pois as estrela na sua volta começam a se movimentar a altas velocidades, algo também que não foi identificado no 47 Tucanae.

No caso de um aglomerado globular, uma evidência para a presença de um buraco negro é o movimento geral das estrelas, o buraco negro funciona como uma colher, recolhendo estrelas e atirando-as a altas velocidades e a grande distâncias, isso gera um sinal que é detectado pelos astrônomos.

Outra evidência são os pulsares, que emitem sinais de rádio facilmente detectados, com a presença do buraco negro de massa intermediária os pulsares são detectados a distâncias maiores do centro do que se o buraco negro não existisse.

combinando essas evidências e usando modelos computacionais, os astrônomos concluíram a presença de um buraco negro com massa equivalente a 2200 vezes a massa do Sol no 47 Tucanae.

Essa descoberta é importante, pois a técnica de detecção e a metodologia usada no processamento dos dados podem ser aplicadas a outras aglomerados globulares na busca por mais buracos negros de massa intermediária, e assim vamos também traçando a linha evolutiva desses que são um dos objetos mais intrigantes do universo.

(via https://www.youtube.com/watch?v=0WCJy3bBKfY)

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carlosalberthreis

7 years ago

A fotografia desta semana mostra fitas de gás e poeira em torno do centro da galáxia espiral barrada NGC 1398. Esta galáxia situa-se na constelação da Fornalha, a aproximadamente 65 milhões de anos-luz de distância da Terra.

Em vez de começarem no meio da galáxia e espiralarem para o exterior, os braços em espiral da NGC 1398 têm origem numa barra direita, formada de estrelas, que corta a região central da galáxia. Uma grande parte das galáxias em espiral — cerca de dois terços — apresenta esta estrutura, no entanto ainda não é claro se e como é que estas barras afectam o comportamento e o desenvolvimento das suas galáxias.

Esta imagem foi criada a partir de dados obtidos pelo instrumento FORS2 (FOcal Reducer/low dispersion Spectrograph 2), montado no Very Large Telescope do ESO (VLT) no Observatório do Paranal, no Chile, e mostra a NGC 1398 em grande detalhe, dos escuros trilhos de poeira que sarapintam os braços em espiral às regiões de formação estelar em tons rosa que aparecem nas regiões mais externas.

A imagem foi criada no âmbito do programa Jóias Cósmicas do ESO, o qual visa obter imagens de objetos interessantes, intrigantes ou visualmente atrativos, utilizando os telescópios do ESO, para efeitos de educação e divulgação científica. O programa utiliza tempo de telescópio que não pode ser usado em observações científicas. Todos os dados obtidos podem ter igualmente interesse científico e são por isso postos à disposição dos astrónomos através do arquivo científico do ESO. Crédito da Imagem: ESO

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