#astronomy 60-Second Astro Information: Planets in Tight Quarters & Kuiper Belt Forays

January 20, 2020 - Comment

Astronomers have calculated the lack of planets round stars in globular clusters, and New Horizons returns observations of worlds within the outer photo voltaic system. Most Planets Misplaced in Globular Clusters At most one-fifth of planetary programs round stars in globular clusters could survive, pupil Melissa Cashion (Texas A&M College) reported on the current assembly


Astronomers have calculated the lack of planets round stars in globular clusters, and New Horizons returns observations of worlds within the outer photo voltaic system.

Most Planets Misplaced in Globular Clusters

At most one-fifth of planetary programs round stars in globular clusters could survive, pupil Melissa Cashion (Texas A&M College) reported on the current assembly of the American Astronomical Society in Honolulu.

Globular cluster NGC 4147

The globular cluster NGC 4147 is about 60,000 light-years from Earth.
ESA / Hubble / NASA / T. Sohn et al.

Globular clusters are dense, long-lived clusters of 1000’s of stars, and it’s unclear how planets fare in such an setting. Cashion and her colleagues simulated clusters with 800,000 stars, with some fraction of them starting with a Jupiter-mass planet circling on the identical distance that Jupiter circles the Solar. The astronomers then adopted the celebrities and their planets over 12 billion years, watching issues unfold.

Most planetary programs had been destroyed within the first billion years, they discovered, with planets leaping to totally different stars — or, in some circumstances, black holes — or being wrenched from their hosts. In uncommon circumstances planets wound up completely circling one other star, however most went rogue, wandering the cluster starless and even ejected from the cluster solely.

A 5% to 20% survival fee is “not too dangerous, contemplating all of the chaos,” Cashion says.

New Horizons Continues Foray into the Kuiper Belt

Ever because the New Horizons spacecraft handed Pluto and set its sights on Arrokoth (previously 2014 MU69), its staff has been taking footage of different, faraway worlds within the Kuiper Belt.

Ultima Thule in color

Arrokoth, as seen in colour by New Horizons throughout its flyby.
NASA / JHUAPL / SWRI / Roman Tkachenko

Though these small our bodies have been nothing however blurry blobs because the craft handed them — at distances from one-tenth to 1 astronomical unit — scientists are nonetheless in a position to study their shapes. The staff watches how the worlds change in brightness over time as they’re seen from totally different angles, then combines that info with Earth-based observations. This work signifies that Kuiper Belt objects have a wide range of shapes, Simon Porter (Southwest Analysis Institute) and colleagues reported on the assembly of the American Astronomical Society in Honolulu.

One, known as 2011 JY31, might be spherical; two others look like conjoined twins, like Arrokoth. A 3rd appears like a binary system. The outcomes add to rising proof that binaries and phone binaries is perhaps widespread within the outer photo voltaic system (see our February 2020 difficulty).



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