The Complex Ion Tail of Comet Lovejoy
Image Credit & Copyright:
Velimir Popov & Emil Ivanov
(IRIDA Observatory)
Explanation:
What causes the structure in Comet Lovejoy's tail?
Comet C/2014 Q2 (Lovejoy),
which is currently at naked-eye brightness and
near its brightest,
has been showing an exquisitely detailed ion tail.
As the name implies, the
ion tail is made of
ionized gas -- gas energized by
ultraviolet light
from the Sun and pushed outward by the
solar wind.
The solar wind is quite structured and sculpted by the Sun's complex and ever
changing magnetic field.
The effect of the variable solar wind combined with different gas jets
venting from the comet's nucleus accounts for the tail's complex
structure.
Following the wind, structure in Comet Lovejoy's
tail can be seen to move outward from the Sun even alter its
wavy appearance over time.
The blue color of the ion tail is dominated by recombining
carbon monoxide
molecules, while the green color of the coma surrounding the head of
the comet is created mostly by a slight amount of recombining
diatomic carbon molecules.
The
featured three-panel mosaic image was taken nine days ago from the
IRIDA Observatory
in
Bulgaria.
Comet Lovejoy made it closest pass to the Earth two weeks ago and will be at its closest to the Sun in about ten days.
After that,
the comet will fade as it heads back into the
outer Solar System, to return only in about 8,000 years.
Approaching Asteroid Ceres
Image Credit:
NASA,
JPL-Caltech,
UCLA, MPS/DLR/IDA/PSI
Explanation:
It is the largest asteroid in the asteroid belt -- what secrets does it hold?
To find out, NASA has sent the
robotic Dawn spacecraft
to explore and map this cryptic 1,000-kilometer wide world:
Ceres.
Orbiting between
Mars and
Jupiter,
Ceres is officially categorized as a
dwarf planet but has never been imaged in detail.
Featured here is a 20-frame video taken a week ago of
Dawn's approach that now rivals even the best
images of Ceres ever taken by the
Hubble Space Telescope.
The video shows enough surface definition to discern its 9-hour rotation period.
On target to
reach Ceres in early March, Dawn will match speeds and attempt
to orbit this previously unexplored body, taking images and data that may help humanity
better understand
not only the nature and history of Ceres but also the
early history of our entire
Solar System.
Infrared Orion from WISE
Image Credit:
WISE,
IRSA,
NASA;
Processing & Copyright :
Francesco Antonucci
Explanation:
The Great Nebula in Orion is an intriguing place.
Visible to the unaided eye, it appears as a small
fuzzy patch in the
constellation of Orion.
But
this image,
an illusory-color four-panel mosaic taken in different bands of
infrared light with the
Earth orbiting
WISE observatory, shows the
Orion Nebula
to be a bustling
neighborhood of recently formed stars,
hot gas, and dark dust.
The power behind much of the
Orion Nebula (M42) is the stars of the
Trapezium star cluster, seen
near the center of the
above wide field image.
The orange glow surrounding the
bright stars pictured here is their own
starlight reflected
by intricate
dust filaments that
cover much of
the region.
The current
Orion Nebula cloud complex, which
includes the
Horsehead Nebula,
will slowly disperse over the next 100,000 years.
Huygens Lands on Titan
Image Credit:
ESA /
NASA /
JPL /
University of Arizona
Explanation:
Delivered by Saturn-bound Cassini, ESA's Huygens probe
touched down on the ringed planet's largest moon
Titan,
ten years ago on January 14, 2005.
These panels show fisheye images made during its
slow descent
by parachute through Titan's dense atmosphere.
Taken by the probe's descent imager/spectral radiometer instrument they
range in altitude from 6 kilometers (upper left) to 0.2 kilometers
(lower right) above the moon's surprisingly Earth-like surface
of dark channels, floodplains, and bright ridges.
But at temperatures near -290 degrees F (-180 degrees C), the liquids
flowing across Titan's surface are methane and ethane, hydrocarbons
rather than water.
After making the
most distant landing
for a spacecraft from Earth, Huygens transmitted data for more than an hour.
The Huygens data and a decade of exploration by Cassini have shown Titan to
be a
tantalizing world hosting a complex
chemistry of organic compounds, dynamic landforms, lakes, seas,
and a possible subsurface ocean of liquid water.
The Soap Bubble Nebula
Credit &
Copyright:
T. Rector
(U. Alaska Anchorage),
H. Schweiker
(WIYN),
NOAO,
AURA,
NSF
Explanation:
Adrift in the
rich star fields
of the constellation Cygnus, this
lovely, symmetric nebula was only recognized a few years ago and
does not yet appear in some astronomical catalogs.
In fact, amateur astronomer
Dave Jurasevich identified
it as a nebula on 2008 July 6 in
his
images of the complex
Cygnus region that included the
Crescent Nebula (NGC 6888).
He subsequently notified the
International Astronomical Union.
Only eleven days later the same object was independently identified by
Mel Helm at
Sierra Remote
Observatories,
imaged by Keith Quattrocchi and Helm, and also submitted to the IAU
as a potentially
unknown nebula.
The nebula, appearing on the left of the
featured image,
is now known as the
Soap Bubble Nebula.
What is the
newly recognized nebula?
Most
probably it is a
planetary nebula, a final phase in the
life of a sun-like star.
In the Arms of NGC 1097
Image Credit &
Copyright:
Steve Mazlin, Jack Harvey, Jose Joaquin Perez;
SSRO-South,
at
PROMPT/CTIO
Explanation:
Spiral galaxy
NGC 1097
shines in southern skies, about
45 million light-years away in the chemical constellation
Fornax.
Its blue spiral arms are mottled with pinkish star forming regions in
this
colorful galaxy portrait.
They seem to have wrapped around a small companion galaxy below
and left of center, about 40,000 light-years from the spiral's luminous
core.
That's not NGC 1097's only peculiar feature, though.
The very deep exposure hints of faint,
mysterious jets, most easily seen to extend well beyond
the bluish arms toward the left.
In fact, four faint jets are ultimately
recognized
in optical images of NGC 1097.
The jets
trace an X centered on the galaxy's nucleus, but probably don't
originate there.
Instead, they could be
fossil star streams,
trails
left over from the
capture and disruption of a much smaller galaxy in the
large spiral's ancient past.
A Seyfert
galaxy, NGC 1097's nucleus also harbors a
supermassive black hole.
Stars and Dust in Corona Australis
Image Credit &
Copyright:
CHART32 Team,
Processing -
Johannes Schedler
Explanation:
Cosmic dust clouds and young, energetic stars inhabit
this
telescopic vista,
less than 500 light-years away toward the northern boundary of
Corona Australis, the Southern Crown.
The dust clouds effectively
block light from
more distant background stars in the
Milky Way.
But the striking complex of reflection nebulae cataloged as
NGC 6726, 6727, and IC 4812
produce a characteristic blue color as light
from the region's young hot stars is
reflected by the cosmic dust.
The dust
also obscures from view stars
still in the process
of formation.
At the left, smaller yellowish nebula NGC 6729 bends around
young variable star
R
Coronae Australis.
Just below it, glowing arcs and loops shocked by outflows from
embedded newborn stars are
identified as
Herbig-Haro objects.
On the sky this field of view spans about 1 degree.
That corresponds to almost 9 light-years at the estimated
distance of the nearby star forming region.
Source -
NASA
