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Space News Update — September 25, 2018 —

Contents

In the News

Story 1:

Recent Tectonics on Mars

Story 2:

Dust Storms on Titan Spotted by Cassini for the First Time

Story 3:

NASA’s GOLD Instrument Captures Its First Image of the Earth

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1. Recent Tectonics on Mars

Mars Express view of Cerberus Fossae These prominent trenches were formed by faults that pulled the planet’s surface

apart less than 10 million years ago.

The images were taken by ESA’s Mars Express on 27 January, and capture part of the Cerberus Fossae system

in the Elysium Planitia region near the Martian equator. Cerberus Fossae cuts through impact craters and hills

along the way, as well as 10 million year old volcanic plains, indicating the relative youth of their formation.

Cerberus Fossae in context. The fossae – meaning ‘ditches’ or ‘trenches’ in Latin –

stretch for more than 1000 kilometers from the northwest to the

southeast.

https://www.esa.int/ESA_Multimedia/Images/2018/09/Mars_Express_view_of_Cerberus_Fossaehttps://www.esa.int/ESA_Multimedia/Images/2018/09/Cerberus_Fossae_in_context

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They vary in width, typically from a few tens of metres to over a kilometre wide, and are thought to be

tectonic features originating from faults that stretch the upper layers of the surface apart.

They could be linked to injections of lava at depth deforming the surface above, perhaps originating from the

trio of volcanoes that are located to the northwest.

Rounded collapse pits observed in the northern part (north is to the right in the main color image) indicate an

early stage of surface sinking; in other places rounded features can be seen connecting up to create longer

cracks.

Scientists studying this region have speculated that the fractures could rupture the crust to a certain depth,

allowing lava or groundwater to escape to the surface.

To the west, as seen in the context image, the Athabasca Valles outflow channel links with the fossae system.

The dark material seen in the largest crater at the north (right) and around some of the cracks is sand blown

by the wind across the Martian surface.

Mars Express celebrates 15 years in orbit this year, and scientists are discussing some of the mission's

highlights at the European Planetary Science Congress this week in Berlin, Germany.

Topographic view of Cerberus Fossae

Source: European Space Agency

______________________________

As of September 18, No Signal Has Been Heard From Opportunity for Nearly 100 Days

The Opportunity team is increasing the frequency of commands it beams to the rover via the dishes of NASA's Deep

Space Network from three times a week to multiple times per day.

No signal from Opportunity has been heard since Sol 5111 (June 10, 2018). That's nearly 100 sols (days) without

communication. It is expected that Opportunity has experienced a low-power fault, perhaps, a mission clock fault

and an up-loss timer fault. The dust storm on Mars continues its decay with atmospheric opacity (tau) over the

rover site below 1.5. The project has been listening for the rover over a broad range of times using the Deep Space

Network Radio Science Receiver and commanding "sweep and beeps" to address a possible complexity with certain

conditions within the mission clock fault. Total odometry remains at 28.06 miles (45.16 kilometers).

Source: NASA Return to Contents

http://www.esa.int/Our_Activities/Space_Science/Mars_Express/From_horizon_to_horizon_Celebrating_15_years_of_Mars_Expresshttps://meetingorganizer.copernicus.org/EPSC2018/oral_programme/29912https://www.esa.int/Our_Activities/Space_Science/Mars_Express/Recent_tectonics_on_Marshttps://mars.nasa.gov/mer/mission/status_opportunityAll.htmlhttps://www.esa.int/ESA_Multimedia/Images/2018/09/Topographic_view_of_Cerberus_Fossae

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2. Dust Storms on Titan Spotted by Cassini for the First Time

Artist’s impression of a dust storm on Titan. Researchers believe that huge amounts of dust can be raised on Titan,

Saturn’s largest moon, by strong wind gusts that arise in powerful methane storms. Such methane storms, previously

observed in images from the international Cassini spacecraft, can form above dune fields that cover the equatorial regions

of this moon especially around the equinox, the time of the year when the Sun crosses the equator.

Data from the international Cassini spacecraft that explored Saturn and its moons between 2004 and 2017 has

revealed what appear to be giant dust storms in equatorial regions of Titan. The discovery, described in a paper

published in Nature Geoscience today, makes Titan the third body in the Solar System where dust storms have been

observed – the other two are Earth and Mars.

The observation is helping scientists to better understand the fascinating and dynamic environment of Saturn’s

largest moon. “Titan is a very active moon,” says Sebastien Rodriguez, an astronomer at the University Paris

Diderot, France, and the lead author of the paper. “We already know that about its geology and exotic hydrocarbon

cycle. Now we can add another analogy with Earth and Mars: the active dust cycle.” Complex organic molecules,

which result from the atmospheric chemistry and, once large enough, eventually fall to the surface, can be raised

from large dune fields around Titan’s equator.

Titan is an intriguing world – in a way quite similar to Earth. In fact, it is the only moon of the Solar System with a

substantial atmosphere and the only celestial body other than our planet where stable bodies of surface liquid are

known to still exist.

There is one big difference though: while on Earth such rivers, lakes and seas are filled with water, on Titan it is

primarily methane and ethane that flows through these liquid reservoirs. In this unique methane cycle, the

hydrocarbon molecules evaporate, condense into clouds and rain back onto the ground.

The weather on Titan varies from season to season, just as it does on Earth. In particular around the equinox, the

time when the Sun crosses Titan’s equator, massive clouds can form in tropical regions and cause powerful

methane storms. Cassini observed such storms during several of its Titan flybys.

When Sébastien and his team first spotted three unusual equatorial brightenings in infrared images taken by Cassini

around the moon’s 2009 northern equinox, they thought these might be exactly such methane clouds. A thorough

investigation revealed they were something completely different, however. “From what we know about cloud

formation on Titan, we can say that such methane clouds in this area and in this time of the year are not physically

possible,” says Sébastien. “The convective methane clouds that can develop in this area and during this period of

http://www.esa.int/ESA_Multimedia/Images/2018/09/Dust_storm_on_Titan

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time would contain huge droplets and must be at a very high altitude, much higher than the 10 km that modelling

tells us the new features are located.”

The researchers were also able to rule out that the features were actually on the surface in the form of frozen

methane rain or icy lavas. Such surface spots would have a different chemical signature and remain visible for much

longer, while the bright features in this study were only visible for 11 hours to five weeks.

Modelling also showed that the features must be atmospheric, but still close to the surface – most likely forming a

very thin layer of tiny solid organic particles. Since they were located right over the dune fields around Titan’s

equator, the only remaining explanation was that the spots were actually clouds of dust raised from the dunes.

Sébastien says that while this is the first ever observation of a dust storm on Titan, the finding is not

surprising. “We believe that the Huygens probe, which landed on the surface of Titan in January 2005, raised a

small amount of organic dust upon arrival due to its powerful aerodynamic wake,” says Sébastien.

“But what we spotted here with Cassini is at a much larger scale. The near-surface wind speeds required to raise

such an amount of dust as we see in these dust storms would have to be very strong – about five times as strong

as the average wind speeds estimated by the Huygens measurements near the surface and with climate models.”

Huygens made only one direct measurement of the speed of the surface wind just before its landing on Titan, and

at that time it was very low, less than 1 metre per second.

“For the moment, the only satisfactory explanation for these strong surface winds is that they might be related to

the powerful gusts that may arise in front of the huge methane storms we observe in that area and season,”

concludes Sébastien.

This phenomenon, called ‘haboob’, can also be observed on Earth with giant dust clouds preceding storms in arid

areas.

The existence of such strong winds generating massive dust storms also implies that the underlying sand can be set

in motion, too, and that the giant dunes covering Titan’s equatorial regions are still active and continually

changing. The winds could be transporting the dust raised from the dunes across large distances, contributing to

the global cycle of organic dust on Titan, and causing similar effects to those that can be observed on Earth and

Mars.

Source: European Space Agency / NASA Return to Contents

This compilation of images from nine

Cassini flybys of Titan in 2009 and 2010

captures three instances when clear bright

spots suddenly appeared in images taken

by the spacecraft’s Visual and Infrared

Mapping Spectrometer. The brightenings

were only visible for a short period of time

– between 11 hours to five Earth weeks –

and cannot be seen in previous or

subsequent images.

By analysing the infrared spectra of these

images, researchers found that these spots

were most likely large clouds of dust

raised from Titan’s dune fields. It is the

first time that dust storms have been

observed on Titan, making this intriguing

moon of Saturn only the third body in the

Solar System featuring an active dust

cycle, after the Earth and Mars.

https://www.esa.int/Our_Activities/Space_Science/Mars_Express/Recent_tectonics_on_Marshttps://www.nasa.gov/feature/jpl/dust-storms-on-titan-spotted-for-the-first-time

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3. NASA’s GOLD Instrument Captures Its First Image of the Earth

Shown here is the “first light” image of ultraviolet atomic oxygen emission (135.6 nm wavelength) from the Earth’s upper

atmosphere captured by NASA’s GOLD instrument. It was taken at approximately 6 a.m. local time, near sunrise in

eastern South America. The colors correspond to emission brightness, with the strongest shown in red and the weakest in

blue. This emission is produced at altitudes around 160 km (note how it extends above the Earth’s surface on the

horizon), when the Earth’s upper atmosphere absorbs high energy photons and particles. The aurora, at the top and

bottom of the image, and daytime airglow, on the right hand side, are also visible. An ultraviolet star, 66 Ophiuchi (HD

164284), is visible above the western horizon of the Earth. Outlines of the continents and a latitude-longitude grid have

been added for reference. (Courtesy LASP/GOLD science team)

NASA’s Global-scale Observations of the Limb and Disk, or GOLD, instrument powered on and opened its cover

to scan the Earth for the first time, resulting in a “first light” image of the Western Hemisphere in the

ultraviolet. GOLD will provide unprecedented global-scale imaging of the temperature and composition at the

dynamic boundary between Earth’s atmosphere and space.

Built by the Laboratory for Atmospheric and Space Physics (LASP) at the University of

Colorado Boulder (CU), the instrument was launched from Kourou, French Guiana, on Jan. 25, 2018,

mounted onboard the SES-14 satellite and reached geostationary orbit in June 2018. After checkout of the

satellite and communications payload, GOLD commissioning—the period during which the instrument

performance is assessed—began on Sept. 4.

Team scientists conducted one day of observations on Sept. 11, during instrument checkout, enabling them to

produce GOLD’s “first light” image shown here. Commissioning will run through early October, as the team

continues to prepare the instrument for its planned two-year science mission.

https://gold.cs.ucf.edu/http://gold.cs.ucf.edu/wp-content/uploads/2018/09/GOLD-first-light.png

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GOLD is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, GOLD is the first NASA

science mission to fly an instrument as a hosted payload on a commercial satellite. Data from the instrument—

comprised of two, identical ultraviolet-imaging spectrographs—will improve our understanding of the Sun’s

impact on the Earth’s upper atmosphere, as well as the effects from terrestrial weather below.

“GOLD is an amazing technological breakthrough,” said GOLD Principal Investigator Richard Eastes, a research

scientist at LASP. “After years of reviews, testing, testing, and more testing, the instrument is finally making

observations of the Earth. The main act has begun. It’s a testament to the engineering and science teams,

who were responsible for building and calibrating the instrument, that we’ve reached this significant mission

milestone.”

Along with NASA’s Ionospheric Connection Explorer, or ICON, scheduled for launch later this fall, GOLD is a

key element of NASA’s program to explore Earth’s boundary with space, as the two missions explore this

unpredictable near-Earth region to determine how it responds to solar and atmospheric inputs.

“The successful launch of GOLD and acquisition of initial data is a fantastic result,” said Bill McClintock, GOLD

instrument scientist at LASP. “Its data will help us understand the critical role the Sun plays in space weather

and allow us to better protect astronauts and our technological assets that we’ve become so reliant upon in

today’s society.”

Changes in near-Earth space can affect our lives on Earth by disrupting the use of satellites for

communications and navigation. The result can be lost messages, aircraft flight delays, interruptions in GPS

signals, and satellite TV outages. Incoming solar energy can also damage spacecraft electronics and detectors,

and expose astronauts to health risks from radiation. The more we understand about the fundamental nature

of our space environment, the better we can protect these interests.

Scientists expect to begin operations of the GOLD instrument in early October 2018.

Source: CU Laboratory for Atmospheric and Space Physics Return to Contents

https://www.nasa.gov/iconhttp://lasp.colorado.edu/home/2018/09/17/nasas-gold-instrument-captures-its-first-image-of-the-earth/

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The Night Sky

Thursday, September 27

• Arcturus shines ever lower in the west-northwest after dark. The narrow kite shape of its constellation,

Bootes, extends two fists at arm's length to Arcturus's upper right; Arcturus is where the tail would be tied on.

• To the right of Bootes, the Big Dipper is now turning more level.

• And during evening at this time of year, the dim Little Dipper "dumps water" into the bowl of the Big Dipper

way down below it. The Big Dipper will dump it back in the evenings of spring.

Friday, September 28

• Late this evening, spot the Pleiades upper left of the Moon as shown here. When the Pleiades climb the

eastern sky in autumn, we see their tiny dipper pattern standing on its handle.

Saturday, September 29

• There's roughly a two-hour window of darkness now between twilight's end and moonrise (for in the world's

mid-northern latitudes). The window gets longer every night this week. • Late tonight when the Moon does

rise, it's in company with Aldebaran — though not necessarily quite as shown here, for the reasons in the

caption at the top of this page.

By Sunday morning the 29th, the Moon and Aldebaran are shining very high toward the south.

Source: Sky and Telescope Return to Contents

Tuesday, September 25

• A week ago, Altair stood straight

above Mars after nightfall. Now

Altair is moving a little to the right of

straight above Mars as seen at this

time.

Why? Stars high in the south appear

to move west faster than stars low

in the south (for those of us in the

mid-northern latitudes). Moreover,

Mars is now moving eastward

(leftward) against the stars behind it

— faster every week.

Wednesday, September 26

• As the stars come out in late

twilight, Cassiopeia is already higher

in the northeast now than the

sinking Big Dipper is in the

northwest. You'll find Cassiopeia's

broad W pattern almost standing on

end.

Bootes and the Big Dipper Credit: Stellarium

https://www.skyandtelescope.com/observing/this-weeks-sky-at-a-glance-september-21-29/

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ISS Sighting Opportunities (from Denver)

Date Visible Max Height Appears Disappears

Tue Sep 25, 7:12 PM 2 min 48° 48° above NE 11° above NE

Tue Sep 25, 8:47 PM 2 min 16° 15° above NW 15° above N

Wed Sep 26, 7:55 PM 3 min 23° 20° above NW 11° above NNE

Thu Sep 27, 8:40 PM 2 min 12° 10° above NW 11° above N

Fri Sep 28, 7:48 PM 3 min 15° 13° above NW 10° above NNE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Time Zone) September 25, Tuesday

1 p.m. – MSNBC Live Interview with NASA Chief Flight Director Holly Ridings (Media Channel)

3 p.m. – RS-25 Engine Test from Stennis Space Center (All Channels)

4 p.m. – Space Station Expedition 57-58 Crew’s Departure from the Gagarin Cosmonaut Training Center in

Star City, Russia for the Baikonur Cosmodrome in Kazakhstan (Media Channel)

September 26, Wednesday

2:15 p.m. - NASA Administrator James Bridenstine testimony before the Senate Commerce Subcommittee

Hearing: Global Space Race: Ensuring the United States Remains the Leader in Space (Public Channel)

September 27, Thursday

6:30 a.m. - Coverage of the Rendezvous and Capture of the JAXA HTV-7 cargo Craft at the Space Station;

Capture scheduled at 8 a.m. EDT (All Channels)

10 a.m. - “Watch this Space: LIVE” - NASA Administrator Jim Bridenstine chats with our latest class of

astronauts (All Channels)

10:30 a.m. - Coverage of the Installation of the JAXA HTV-7 Cargo Craft to the Space Station (Media

Channel)

12:50 p.m. – Space Station In-Flight Educational Event with the McGovern Medical School in Houston,

Texas, and NASA astronaut Serena Aunon-Chancellor (All Channels)

Watch NASA TV online by going to the NASA website. Return to Contents

http://spaceflight.nasa.gov/realdata/sightings/cities/skywatch.cgi?country=United+Stateshttp://www.nasa.gov/multimedia/nasatv/schedule.html

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Space Calendar

Sep 25 - Azerspace 2 (Intelsat 38)/ Horizons 3e Ariane 5 Launch

Sep 25 - Comet C/2017 U4 (PANSTARRS) Perihelion (7.724 AU)

Sep 25 - Apollo Asteroid 2018 SK Near-Earth Flyby (0.034 AU)

Sep 25 - Apollo Asteroid 2007 TV18 Near-Earth Flyby (0.052 AU)

Sep 25 - Asteroid 5062 Glennmiller Closest Approach To Earth (0.932 AU)

Sep 25 - Asteroid 82332 Las Vegas Closest Approach To Earth (1.568 AU)

Sep 25 - Asteroid 132904 Notkin Closest Approach To Earth (2.440 AU)

Sep 25 - Aeronautics Research and Technology Roundtable Fall, Washington DC

Sep 25-27 - NASA Innovative Advanced Concepts (NIAC) Symposium, Boston, Massachussetts

Sep 25-29 - Workshop: Polar Perspectives - Advancing Our Understanding of the Sun, Boulder, Colorado

Sep 25-29 - Joint 14th Quadrennial iCACGP Symposium/15th IGAC Science Conference 2018, Takamatsu, Japan

Sep 26 - Comet 131P/Mueller Closest Approach To Earth (1.544 AU)

Sep 26 - Comet 77P/Longmore At Opposition (3.564 AU)

Sep 26 - Apollo Asteroid 2018 RX3 Near-Earth Flyby (0.051 AU)

Sep 26 - Amor Asteroid 2013 US8 Near-Earth Flyby (0.094 AU)

Sep 26 - Apollo Asteroid 1865 Cerberus Closest Approach To Earth (0.611 AU)

Sep 26 - Asteroid 2933 Amber Closest Approach To Earth (1.503 AU)

Sep 26 - Asteroid 5036 Tuttle Closest Approach To Earth (2.670 AU)

Sep 26-28 - NASA Techno-Signatures Workshop (NTW18), Houston, Texas

Sep 26-28 - 8th International Systems & Concurrent Engineering for Space Applications Conference (SECESA 2018), Glasgow, United Kingdom

Sep 26-28 - 1st Workshop on High Energy Theory and Gender, Geneva, Switzerland

Sep 26-28 - 2nd International Conference & Exhibition: Advanced Geospatial Science & Technology (TeanGeo 2018), Tunis, Tunisia

Sep 26-29 - Conference: Cosmology on Small Scales 2018 - Dark Matter Problem and Selected Controversies in Cosmology, Prague, Czech Republic

Sep 27 - Comet 251P/LINEAR Closest Approach To Earth (2.699 AU)

Sep 27 - Comet C/2017 P2 (PANSTARRS) At Opposition (3.015 AU)

Sep 27 - Apollo Asteroid 2018 SM1 Near-Earth Flyby (0.017 AU)

Sep 27 - Apollo Asteroid 2018 SS1 Near-Earth Flyby (0.017 AU)

Sep 27 - Apollo Asteroid 2018 RA8 Near-Earth Flyby (0.066 AU)

Sep 27 - Atira Asteroid 434326 (2004 JG6) Closest Approach To Earth (0.699 AU)

Sep 27 - Asteroid 2925 Beatty Closest Approach To Earth (1.656 AU)

Sep 27 - Event: Becoming Interplanetary - What Living on Earth Can Teach Us about Living on Mars, Washington DC

Sep 27 - Lecture: Decrease in Hysteresis of Planetary Climate for Planets with Long Solar Days, Ithaca, New York

Sep 27 - Seminar: Scale-Dependent Measurements of Meteorite Strength and the Implications for Asteroid Fragmentation, Houston, Texas

Sep 27-29 - Space Generation Congress 2018, Bremen, Germany

Source: JPL Space Calendar Return to Contents

https://www.satbeams.com/satellites?id=2674http://space.skyrocket.de/doc_sdat/horizons-3e.htmhttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2017+U4;view=Farhttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2018+SKhttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2007+TV18http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=5062http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=82332http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=132904https://www8.nationalacademies.org/pa/projectview.aspx?key=50607#MeetingId10105http://www.cvent.com/events/2018-niac-symposium/event-summary-9740b1039c4946e481c28436d7d96be6.aspxhttps://www2.hao.ucar.edu/PolarPerspectives2018http://www.igacproject.org/iCACGP-IGAC2018http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=131Phttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=77Phttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2018+RX3http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2013+USBhttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=1865http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2933http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=5036https://www.hou.usra.edu/meetings/technosignatures2018/https://atpi.eventsair.com/QuickEventWebsitePortal/secesa-2018/secesahttps://atpi.eventsair.com/QuickEventWebsitePortal/secesa-2018/secesahttps://indico.cern.ch/event/714346/http://www.teangeo.org/En/http://www.teangeo.org/En/http://css2018.math.cas.cz/http://css2018.math.cas.cz/http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=251Phttp://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2017+P2http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2018+SM1http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2018+SS1http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2018+RA8http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=434326http://ssd.jpl.nasa.gov/sbdb.cgi?orb=1;sstr=2925https://www.decolonizemars.org/becoming-interplanetary/http://astro.cornell.edu/lectures-colloquiahttps://www.lpi.usra.edu/seminars/#3158https://www.lpi.usra.edu/seminars/#3158https://spacegeneration.org/sgc2018http://www2.jpl.nasa.gov/calendar/#1809

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Food for Thought

Astronomers Use Novel Technique to Probe Stellar Rotation

Sun-like stars rotate differentially, with the equator rotating faster than the higher latitudes. The blue arrows in the figure

represent rotation speed. Differential rotation is thought to be an essential ingredient for generating magnetic activity and

starspots. Such differential rotation was inferred in a sampling of stars with similar masses to the Sun’s by studying the

oscillatory motions of convective cells near the surface. Image: MPS/Mark Garlick.

Sunspots have been observed for centuries, with the first written records made by Chinese astronomers in 364

BC. In 1612, Galileo observed sunspots and concluded the Sun was rotating.

But astronomers now know stars do not rotate like solid spheres; different latitudes rotate at different

velocities, a phenomenon known as “latitudinal differential rotation.” One full rotation takes 25 days at the

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Sun’s equator, but about 31 days near the poles. Differential rotation is thought to play a major role in

generating magnetic fields and sunspots.

Now, researchers with New York University, the Max Planck Institute for Solar System Research (MPS) and the

University of Göttingen have measured differential rotation patterns in 13 stars with masses similar to the

Sun’s, finding faster equatorial speeds as expected.

But they were surprised to find the measured velocities were higher than those observed with the Sun, with

equatorial regions rotating up to twice as fast as higher latitudes. The discrepancy was not predicted by

numerical models.

The velocities were calculated based on the effects of acoustic oscillations generated by convective cells in the

stars’ outer layers. The frequencies of those oscillations were used to determine how fast different latitude

zones were rotating.

“Using observations from NASA’s Kepler mission, we can now probe the interior of stars with astero-

seismology and determine their rotational profiles at different latitudes and depths,” said Laurent Gizon,

director at MPS.

“Modes of oscillation that propagate in the direction of rotation move faster than the modes that propagate in

the opposite direction, thus their frequencies are slightly different,” he said. “Our best measurements all reveal

stars with solar-like rotation.”

The research shows the potential of astero-seismology for probing stellar interiors.

“Information about stellar differential rotation is key to understanding the processes that drive magnetic

activity,” Gizon said. But, he cautioned, large numbers of stars must be studied before researchers will be able

to draw conclusions.

Source: Max Planck Institute for Solar System Research/Astronomy Now Return to Contents

http://www.mps.mpg.de/A-new-twist-on-stellar-rotationhttps://astronomynow.com/2018/09/21/astronomers-surprised-how-fast-a-sampling-of-sun-like-stars-rotate/

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Space Image of the Week

Rover 1A Hops on Asteroid Ryugu

Image Credit & Copyright: ISAS, JAXA, Hayabusa2 Mission

Explanation: Two small robots have begun hopping around the surface of asteroid Ryugu. The rovers, each

the size of a small frying pan, move around the low gravity of kilometer-sized 162173 Ryugu by hopping,

staying aloft for about 15 minutes and typically landing again several meters away.

On Saturday, Rover 1A returned an early picture of its new home world, on the left, during one of its first

hops. On Friday, lander MINERVA-II-1 detached from its mothership Hayabusa2, dropped Rovers 1A and 1B,

and then landed on Ryugu.

Studying Ryugu could tell humanity not only about Ryugu's surface and interior, but about what materials

were available in the early Solar System for the development of life. Two more hopping rovers are planned for

release, and Hayabusa2 itself is scheduled to collect a surface sample from Ryugu and return it to Earth for

detailed analysis before 2021.

Source: NASA APOD Return to Contents

https://apod.nasa.gov/apod/ap180924.htmlhttps://apod.nasa.gov/apod/image/1809/Ryugu01_Rover1aHayabusa2_960.jpg