Celebrating Five Years At Jupiter!

Masterpieces of Mesozoic Seas

Say hello to globular cluster 47 Tucanae 👋

This glittery spray of ancient stars is about 16,700 light-years away from Earth toward the constellation Tucana. Globular clusters like this one are isolated star cities, home to hundreds of thousands of stars that are held together by their mutual gravity. And like the fast pace of cities, there’s plenty of action in these stellar metropolises. The stars are in constant motion, orbiting around the cluster’s center.

Past observations have shown that the heavyweight stars tend to crowd into the “downtown” core area, while lightweight stars reside in the less populated suburbs. But as heavyweight stars age, they rapidly lose mass, cool down and shut off their nuclear furnaces. After the purge, only the stars’ bright, superhot cores – called white dwarfs – remain. This weight loss program causes the now lighter-weight white dwarfs to be nudged out of the downtown area through gravitational interactions with heftier stars.

Until these Hubble observations, astronomers had never seen the dynamic conveyor belt in action. The Hubble results reveal young white dwarfs amid their leisurely 40-million-year exodus from the bustling center of the cluster.

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Shout out to all of my awake friends!

The Milky Way over Snow-Capped Himalayas

Can you tell us something about j1407b?

J1407b is an exoplanet (but it can also be a brown dwarf) very interesting, orbiting its star J1407. It is larger than Saturn or Jupiter, and is surrounded by a ring system that is about 200 times larger than the rings of Saturn, very different from what we are accustomed to see.

Thirty-seven rings extending 90 million kilometers from the planet — over half the distance from the Earth to the sun — encircle the world. These planetary rings are the first found outside the solar system.

This exoplanet is 434 light-years away in the constellation Centaurus.

J1407b could house moons that could be formed by the material of the rings. One of their moons could be as large as Mars or Earth, and could orbit between the gaps of the rings, shaping them.

Astronomers expect the rings to become thinner in the next million years and eventually disappear as they form satellites from the material of the rings.

The discovery of the J1407 system and its unusual eclipses were reported by the team led by astronomer Eric Mamajek of the University of Rochester in 2012. The orbital period of J1407b is estimated at about a decade.

Simulation of the eclipse of the star J1407 by the ring system around its putative exoplanet J1407b. Each time a ring passed in front of the star, it dimmed. When entering a gap, the star brightened up again. Graphing the highs and lows, scientists created a profile of the ring system.

What the rings of J1407b would look like in our sky (above the Old Observatory in Leiden, Netherlands) if it was located where Saturn is now.

image 1°, image 2°, image 3°, image 4, image 5° & image 7°

Here are some links if you want to read more about it: here, here and here.

NGC 4590 (M68) Globular Cluster

33,000 light years from the Earth, this globular cluster has an odd orbit around our galaxy, orbiting like a comet does around a star, and moving away as far as 100,000 light years from the centre. 

It’s theorised that it’s likely a captured cluster, and appears to be undergoing core collapse, where the gravitational influence of the entire cluster bares down at the centre and causes black holes and dense stars to slowly migrate towards the centre, much as our own galaxy has the same mechanism creating the central black hole. 

Ratnagiri petroglyph, India. 10,000 BC...

Saturn and Dione - October 2 2011

NASA/JPL-Caltech/SSI/Kevin M. Gill

Cassini spacecraft captured this image of Saturn and Titan