Hello Space Fans and welcome to another edition of Space Fan News. This week, astronomers
using the Canada-France-Hawaii Telescope announce a new dwarf planet discovery in the outer
solar system and astronomers using ESO’s Very Large Telescope show us the deepest look
yet into the magnificent Orion Nebula.
The largest and most distant object orbiting the Sun was observed by astronomers on Mauna
Kea’s Canada-France Hawaii Telescope.
Designated 2015 RR 245 by the International Astronomical Union’s Minor Planet Center,
this object is currently some 64 astronomical units (9½ billion km) from the Sun, more
than twice Neptune's distance. And despite being extremely faint, it could be as large
as 700 km (450 miles) across.
It has an orbit, outlined here in yellow, that is highly elliptical and takes it well
beyond anything we’ve ever seen, at its farthest, 2015 RR245 extends well past 120
astronomical units or 18 billion kilometers from the Sun.
It was first images by the Outer Solar Systems Origins Survey which attempts to map the orbits
of objects in the outer regions of our solar system.
This dwarf planet is the largest found in the survey and which has so far found over
500 of these so-called TransNeptunian worlds. These are bodies that orbit outside the planet
Neptune and The IAU's Minor Planet Center has found 1,491 objects in orbits like this
and another 501 in the outer solar system that occupy odd, usually quite elliptical orbits.
On average, one more gets added to the list about every 5 days.
This minor planet was found by astronomers in February 2016 using OSSOS images taken
in September 2015.
The vast majority of the dwarf planets like RR245 were destroyed or thrown from the Solar
System in the chaos that ensued as the giant planets moved out to their present positions:
RR245 is one of the few dwarf planets that has survived to the present day — along
with Pluto and Eris, the largest known dwarf planets.
RR245 now circles the Sun among the remnant population of tens of thousands of much smaller
trans-Neptunian worlds, most of which orbits is unseen.
Worlds that journey far from the Sun have exotic geology with landscapes made of many
different frozen materials, as the recent flyby of Pluto by the New Horizons spacecraft showed.
Because it is so far away, it takes 2015 RR 245 700 years to go around the Sun and it
has only been observed for a tiny fraction of that time (one year) and so they are still
refining the orbit but over the years astronomers will get a better idea of it’s path more
precisely and at some point, they’ll give it a name.
And in case you were wondering, the way that works is the members of the OSSOS team, since
they were the ones who found it, get to submit a recommendation for a name for consideration
by the International Astronomical Union, which is the only authority when it comes to naming things in the sky.
Previous surveys have mapped almost all the brighter dwarf planets. 2015 RR245 may be
one of the last large worlds beyond Neptune to be found until larger telescopes, such
as LSST, come online in the mid 2020s.
I’ll keep you posted.
Next, astronomers using the Very Large Telescope in Chile took the deepest picture of the venerable
Orion Nebula ever taken.
Using the Hawk I infrared instrument, we now have an image of not only spectacular beauty,
but one that has revealed an abundance of faint brown dwarfs and isolated planetary-mass
objects. The very presence of these low-mass bodies provides an exciting insight into the
history of star formation within the nebula itself.
This new image reveals an unexpected wealth of very-low-mass objects, which in turn suggests
that the Orion Nebula may be forming proportionally far more low-mass objects than closer and
less active star formation regions. The famous Orion Nebula is about 24 light-years
across and lies within the constellation of Orion. It is visible from Earth with the naked
eye, as a fuzzy patch in Orion’s sword. Some nebulae, like Orion, are strongly illuminated
by ultraviolet radiation from the many hot stars born within them, such that the gas
is ionised and glows brightly. The relative closeness of the Orion Nebula
makes it an ideal testbed to better understand the process and history of star formation,
as well as determine how many stars of different masses form.
What they do is astronomers count up how many objects of different masses form in regions
like the Orion Nebula to try to understand the star-formation process. Before this research
the greatest number of objects were found with masses of about one quarter that of our Sun.
These observations also hint that the number of planet-sized objects might be far greater
than previously thought. While the technology to readily observe these objects does not
exist yet, European Extremely Large Telescope (E-ELT) being built by ESO and scheduled to
begin operations in 2024, is designed to pursue this as one of its goals.
And of course, I will let you know.
Well, that’s it for this week Space Fans. Thanks to all of my Patreon Supporters for
making SFN possible and thank you for watching, and as always,
Keep Looking Up!