'ASTEROID' 2010 KQ IS ARTIFICIAL
The Register
An unknown object that recently approached the Earth is almost
certainly artificial in origin rather than being an asteroid. Object
2010 KQ was detected by the Catalina Sky Survey in Arizona last month
and subsequently tracked by the Near-Earth Object Program based at the
Jet Propulsion Laboratory in California. Observations with the
infrared telescope in Hawaii indicate that 2010 KQ's spectral
characteristics do not match any of the known asteroid types, and the
object's magnitude suggests that it is only a few metres in size. The
object has apparently made a close pass by the Earth, coming in almost
to the distance of the Moon's orbit, and is now headed away again.
The object has used no propulsion during the time it has been under
observation. However the Spacewatch scientists believe that it must
have moved under its own power at some point, given its position and
velocity. Its orbit is very similar to that of the Earth, and one
would not expect a naturally-occurring object to remain in such an
orbit for very long. It is thought likely to be a booster stage from
an interplanetary mission of the past, now drifting back past the
Earth and out again. The next visit will probably be 2036, at which
time there is a small chance that 2010 KQ will enter the atmosphere
and burn up.
ECLIPSING WHITE-DWARFBINARY SYSTEM DISCOVERED
Science Daily
Astrophysicists have identified two white-dwarf stars in an eclipsing
binary system, allowing the first direct radius measurement of a rare
white dwarf composed of pure helium. White dwarfs are the very dense
remnants of stars like the Sun, with dimensions comparable to that of
the Earth. A star becomes a white dwarf when it has exhausted its
nuclear fuel and all that remains is the dense inner core, typically
made of carbon and oxygen. One of the stars in the newly discovered
binary is a relatively rare helium-core white dwarf with a mass only
10-20% of that of the Sun. The existence of such stars has been known
for more than 20 years. Theoretical work predicted that they should
be hotter and larger than ordinary white dwarfs, but until now their
size had never been measured. Photometric monitoring of the unusual
white-dwarf binary system NLTT 11748 with the Faulkes Telescope North
of the Las Cumbres Observatory, with a frequency of about one exposure
a minute, showed a few consecutive images where the star was slightly
fainter. There proved to be two three-minute eclipses during every
5.6-hour orbit. The discovery was confirmed by the 10-m Keck
telescope just five weeks after the first observation. Scientists
were able to measure the radial velocity of the more-luminous star as
it orbited its fainter companion, which is also a white dwarf but is a
more ordinary one, composed mostly of carbon and oxygen and with about
70% of the mass of the Sun. The ordinary one is more massive and also
much smaller than the helium dwarf, and is 30 times fainter. The
formation of such a binary system containing an extremely-low-mass
helium white dwarf must be the result of mass loss and transfer
between the two original stars.
CAUSE OF BLACK-HOLE OUTBURSTS
NASA
Data from an ongoing survey by the Swift satellite have helped
astronomers understand why a small percentage of black holes emit vast
amounts of energy. Only about 1% of super-massive black holes exhibit
that behaviour. The new findings confirm that black holes 'light up'
when galaxies collide, and the data may offer insight into the future
behaviour of the black hole in our own Milky Way galaxy. The intense
emission from galactic nuclei arises near a super-massive black hole
containing between a million and a billion times the Sun's mass.
Giving off as much as 10 billion times the Sun's energy, some active
galactic nuclei (AGN) are among the most luminous objects in the
Universe. They include quasars and blazars.
Before Swift's hard-X-ray survey, astronomers could not be sure that
they had counted the majority of the AGN. Thick clouds of dust and
gas surround the black hole in an active galaxy, and can block
ultraviolet, optical and low-energy ('soft') X-rays. Infrared
radiation from warm dust near the black hole can pass through the
material, but it can be confused with emissions from the galaxy's
star-forming regions. Hard X-rays can allow scientists to detect
directly the energetic processes occurring near the black hole. Since
2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping
the sky in hard X-rays. The survey, which is sensitive to AGN as far
as 200 Mpc (megaparsecs; 1 parsec is about 3.26 light-years) away,
uncovered dozens of previously unrecognized systems. The team has
found that about a quarter of the BAT galaxies are in mergers or close
pairs; theoreticians had already thought that mergers should trigger
AGNs.
OLD MOON ROVER RETURNS LASER FLASHES TO EARTH
NASA
A Soviet robot lost on the Moon for the past 40 years has been found
again, and is returning surprisingly strong laser pulses. Scientists
beamed a laser on Lunokhod 1's position, and were surprised by the
power of the reflection. The scientists from the University of
California will attempt to get the robot working again. Almost
forgotten in the lore of the Apollo-era space race, Lunokhod 1 was one
of the greatest successes of the Soviet lunar-exploration programme.
The remote-controlled rover travelled almost 7 miles during an
11-month tour, relaying thousands of TV images and hundreds of
high-resolution panoramas back to Earth. It also sampled and analyzed
lunar soil at 500 locations. Then Lunokhod 1 was lost -- until last
month, when the Lunar Reconnaissance Orbiter found it again.
NEW NATIONAL TELESCOPE AT LA SILLA
ESO
A new robotic telescope has seen 'first light' at ESO's La Silla
Observatory in Chile. TRAPPIST (TRAnsiting Planets and PlanetesImals
Small Telescope) is a collaboration between the University of Liège
and the Geneva Observatory. The telescope is installed in the
building that housed the old Swiss T70 telescope. The project is on a
fast track: it took only two years between taking the decision to
build and first light. It is a lightweight 0.6-m robotic telescope,
fully automated and moving precisely across the sky at a high speed.
The observing programme is prepared in advance and the telescope can
perform a full night of observations unattended. A meteorological
station monitors the weather continuously and decides to close the
dome if necessary.
TRAPPIST is intended to study planetary systems through two
approaches: the detection and characterization of planets outside the
Solar System (exo-planets), and the study of comets orbiting the Sun.
It will make high-precision measurements of brightness dips that might
be caused by exo-planet transits. The astronomers behind TRAPPIST
will work closely with those using HARPS on the 3.6-m telescope and
CORALIE on the Swiss 1.2-m Euler telescope, both at La Silla.
TRAPPIST will also be used for the study of southern comets. The
telescope is equipped with special cometary filters to allow
astronomers to study regularly and in detail the ejection of several
types of molecules by comets.
Topic: Mid June Astronomy Bulletin (Read 687 times)