Page 13 - Astronomy - October 2017 USA

ASTRONEWS BROWN DWARF DANCE. Astronomers using the Hubble Space Telescope to watch a pair of brown dwarfs
6 light-years away have determined there is no third object in the system, as was originally suspected.

A new look at the Orion Nebula QUICK TAKES

SPECIAL DELIVERY
Observations of Comet 67P/
Churyumov–Gerasimenko
suggest comets may have
delivered up to 22 percent of
Earth’s atmospheric xenon.
•
HEAT IT UP
The network of valleys
surrounding Mars’ Lyot Crater
was likely carved by water
from an ice layer melted by hot
ejecta from the impact.
•
INFINITE DIVERSITY
Samples collected by the
Curiosity rover near Mars’
Mount Sharp show diverse
mineral content suggestive of
changing conditions in the area.
•
LOCKED IN PLACE
A Lowell Observatory-led study
shows that massive galaxy
cluster centers have been
GBO/AUI/NSF aligned with their surroundings
for 10 billion years.
STAR-FORMING STRING. The Orion Nebula is visible to the naked eye, located just beneath the Hunter’s three-star belt. But gas •
and dust hide much of what’s going on in this nearby stellar nursery. Using radio observations taken of the nebula with the Robert C. BIG BANGS
Byrd Green Bank Telescope in West Virginia, astronomers have identified a filament of ammonia molecules spanning 50 light-years. Researchers from the
The ammonia is visible as orange in this composite image, which also shows other gas, imaged with NASA’s Wide-field Infrared University of Colorado Boulder
Survey Explorer telescope, in blue. Ammonia in particular traces the dense gas that ultimately collapses to form stars. Studying the found that hot intracluster gas
concentration and location of ammonia in the Orion Nebula will help astronomers determine whether its densest regions of gas are may result from turbulence as
stable or likely to form new stars in the near future. — A. K. massive galaxy clusters collide.
•
JETTING OFF
LIGO detects third gravitational wave Astronomers are using data
from the Chandra X-ray
Observatory to trace previous
LIGO has detected gravitational outbursts in the R Aquarii
waves for a third time, helping GW150914 binary system, as well as predict
astronomers further understand future events by watching
black holes. 60 blobs of hot gas in the jets
All objects distort the fabric of GW170104 associated with the stars.
space-time by some amount. The 50 •
interaction of more massive objects LIGO detections METEORITE MYSTERY
can cause detectable “ripples” in it, 40 Researchers have used high-
sort of like a ripple in a pond, except Black hole mass (solar masses) 70 pressure experiments to
these ripples move at the speed of 30 GW151226 determine how meteorites can
contain multiple types of
light. But these ripples are also small 20 X-ray studies LIGO/CALTECH/SONOMA STATE (AURORE SIMONNET) silica, despite the differing
because gravity is the weakest of the LVT151012 conditions required for them
fundamental forces. 10 (tentative to form. The results shed light
Finding ripples of gravity is there- detection) on impact processes
fore far more difficult than, say, 0 throughout the solar system.
detecting a massive electromagnetic •
event. That’s why LIGO, short for the FILLING THE GAPS. LIGO detectors have discovered a pair of merging black holes EXTREME HEAT
Laser Interferometer Gravitational- with masses higher than those detected in X-rays. On the left are previously known The gas giant planet KELT-9b
wave Observatory, uses two (soon to black holes found via X-rays; on the right are three strong and one tentative gravitational has a dayside temperature of
be three) locations to tune in to espe- wave detections made by the observatory, sorted by mass on the vertical axis. 7,800° F (4,300° C), making it
cially violent events, like the merger hotter than many stars.
of two black holes. When black holes black hole 49 times the mass of the Physical Review Letters, may indicate a •
merge, the magnitude of their gravi- Sun. A black hole of this mass helps shift toward one of the LIGO team’s GALACTIC
tational waves changes from the “fill in” the spectrum of black holes, hopes: that detecting gravitational WEIGHT LOSS
effects of a “pebble” in the pond of as it falls between the masses of the waves may become commonplace As galaxies join groups of
space to the equivalent of tossing in a two black hole mergers previously events. The addition of the European 20–30 members, they lose up
boulder, sending out much larger detected by LIGO (62 and 21 solar Gravitational Observatory’s Advanced to 40 percent of their initial
gravitational waves in all directions. masses). Before LIGO, astronomers Virgo detector, as well as a third mass, astronomers have
LIGO’s third detection is a merger had measured black holes a few LIGO observatory recently approved found. This is more than the
that took place 3 billion light-years times the mass of the Sun and those for construction in India, will go a mass loss experienced by
away and reached Earth on January 4. several million times the mass of the long way toward increasing the sensi- single galaxies falling into
The event occurred when two black Sun, with nothing in between. tivity of the project in the future. clusters of hundreds or
holes combined to create a single The results, published June 1 in — John Wenz thousands of galaxies. — A. K.

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