All posts by Tom

Comet 46P/Wirtanen

Comet 46P/Wirtanen is in our night sky and visible without a telescope. I cannot say it is a naked-eye object, but I will qualify that by telling you I have not been out in the most favorable time. Most of my viewing has been at 03:00 to 04:00 and if I could get outside a couple hours earlier I might indeed glimpse it. So I am looking to the west and not so much to the south. I do have pretty good skies too so if you have any light pollution at all you will need assistance in seeing Wirtanen (in my experience that is).

If you have even a small pair of binoculars you are all set. I chose the image above because it is a great facsimile of what I see (image from: Astronomy Sketch of the Day). If you have even a small telescope you may be able to see a tail.

How do you find it? The best finders chart I’ve found is here and the chart comes from the Comet Wirtanen Observing Campaign website.

Hopefully I will be able to get one of my scopes on it this weekend. From the weather forecast here that is in doubt, so it’s either brave the -20 C temps or hope the clouds and rain (!) stays away.

ICESat-2 Delivers the Icy Data

ICESat-2 is delivering great data. If you are a student in need of a science project check out the project website and you are sure to find something useful including actual data – one of the best project websites around.

NASA: Less than three months into its mission, NASA’s Ice, Cloud and land Elevation Satellite-2, or ICESat-2, is already exceeding scientists’ expectations. The satellite is measuring the height of sea ice to within an inch, tracing the terrain of previously unmapped Antarctic valleys, surveying remote ice sheets, and peering through forest canopies and shallow coastal waters.

With each pass of the ICESat-2 satellite, the mission is adding to datasets tracking Earth’s rapidly changing ice. Researchers are ready to use the information to study sea level rise resulting from melting ice sheets and glaciers, and to improve sea ice and climate forecasts.

In this image, sea ice forms in the open water between floes, called leads, in the Bellingshausen Sea. ICESat-2 is able to detect the thin sea ice, allowing scientists to more accurately track seasonal ice formation.

Image Credit: NASA/Kate Ramsayer

Bellingshausen Sea

Water on Asteroid Bennu?

A new look at asteroid Bennu from the OSIRIS-REx spacecraft courtesy of: NASA, Goddard, and the University of Arizona. If you have not seen it there is a very good animated version of Bennu’s rotation, be warned if you have a slow connection, it is a large file; just be patient it is worth the wait. Video at asteroidmission.org.

The big news, really big news is there may be water in the clays on Bennu:

NASA: Recently analyzed data from NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission has revealed water locked inside the clays that make up its scientific target, the asteroid Bennu.

During the mission’s approach phase, between mid-August and early December, the spacecraft traveled 1.4 million miles (2.2 million km) on its journey from Earth to arrive at a location 12 miles (19 km) from Bennu on Dec. 3. During this time, the science team on Earth aimed three of the spacecraft’s instruments towards Bennu and began making the mission’s first scientific observations of the asteroid. OSIRIS-REx is NASA’s first asteroid sample return mission.

Data obtained from the spacecraft’s two spectrometers, the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) and the OSIRIS-REx Thermal Emission Spectrometer (OTES), reveal the presence of molecules that contain oxygen and hydrogen atoms bonded together, known as “hydroxyls.” The team suspects that these hydroxyl groups exist globally across the asteroid in water-bearing clay minerals, meaning that at some point, Bennu’s rocky material interacted with water. While Bennu itself is too small to have ever hosted liquid water, the finding does indicate that liquid water was present at some time on Bennu’s parent body, a much larger asteroid.

“The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” said Amy Simon, OVIRS deputy instrument scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”

Additionally, data obtained from the OSIRIS-REx Camera Suite (OCAMS) corroborate ground-based telescopic observations of Bennu and confirm the original model developed in 2013 by OSIRIS-REx Science Team Chief Michael Nolan and collaborators. That model closely predicted the asteroid’s actual shape, with Bennu’s diameter, rotation rate, inclination, and overall shape presented almost exactly as projected.

One outlier from the predicted shape model is the size of the large boulder near Bennu’s south pole. The ground-based shape model calculated this boulder to be at least 33 feet (10 meters) in height. Preliminary calculations from OCAMS observations show that the boulder is closer to 164 feet (50 meters) in height, with a width of approximately 180 feet (55 meters).

Bennu’s surface material is a mix of very rocky, boulder-filled regions and a few relatively smooth regions that lack boulders. However, the quantity of boulders on the surface is higher than expected. The team will make further observations at closer ranges to more accurately assess where a sample can be taken on Bennu to later be returned to Earth.
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InSight On Mars

Very nice image from the surface of Mars from the InSight Lander, thanks to NASA and JPL-Caltech. Do you know what that hexagonal copper colored box is? Its the Seismic Experiment for Interior Structure instrument or SEIS and at some point soon will be placed on the surface and it apparently functions properly because it could feel vibrations from the Martian wind – see here.

Marsquakes? I hope so, but we will have to wait and see.

NASA: This image from InSight’s robotic-arm mounted Instrument Deployment Camera shows the instruments on the spacecraft’s deck, with the Martian surface of Elysium Planitia in the background.

The color-calibrated picture was acquired on Dec. 4, 2018 (Sol 8). In the foreground, a copper-colored hexagonal cover protects the Seismic Experiment for Interior Structure instrument (SEIS), a seismometer that will measure marsquakes. The gray dome behind SEIS is the wind and thermal shield, which will be placed over SEIS. To the left is a black cylindrical instrument, the Heat Flow and Physical Properties Probe (HP3). HP3 will drill up to 16 feet (5 meters) below the Martian surface, measuring heat released from the interior of the planet. Above the deck is InSight’s robotic arm, with the stowed grapple directly facing the camera.

To the right can be seen a small portion of one of the two solar panels that help power InSight and part of the UHF communication antenna.

JPL manages InSight for NASA’s Science Mission Directorate. InSight is part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama.

A number of European partners, including France’s Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR), are supporting the InSight mission. CNES, and the Institut de Physique du Globe de Paris (IPGP), provided the SEIS instrument, with significant contributions from the Max Planck Institute for Solar System Research (MPS) in Germany, the Swiss Institute of Technology (ETH) in Switzerland, Imperial College and Oxford University in the United Kingdom, and JPL. DLR provided the HP3 instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiologí­a (CAB) supplied the wind sensors.

For more information about the mission, go to https://mars.nasa.gov/insight.

Delta IV Heavy Staggered Start

I was watching coverage of the NROL-71 launch and United Launch Alliance usually precedes launch coverage with informative topics. One of the ones today was the fireball at launch time, just before leaving the ground.

What happened with the launch? As the rocket was about to fully light – we got to the fireball part – then everything stopped.

At this point I am guessing a 24 hour turn-around but that could be very optimistic so the delay could be longer.

Contrived View of the Solar North Pole

We have not seen an image of the solar poles since the Ulysses mission ended in 2009. Now ESA has figured out a way to contrive a view of the poles once again. Looking at the image it appears to be a little “off” in the way it is put together, but what a nice effort – great job ESA! This technique is quite timely because while we are at the bottom of a solar cycle there are signs a new solar cycle could be in the very-very early stages of beginning.

A tiny sunspot formed a couple of weeks ago at a very high latitude with the correct magnetic configuration for the next cycle. Now that sunspot apparently disappeared because I’ve not seen it since, however there is hope and high latitude sunspots a good sign.

Image: ESA/Royal Observatory of Belgium

ESA:  We’ve sent numerous missions into space to study the Sun; past and present solar explorers include ESA’s Proba-2 (PRoject for OnBoard Autonomy 2) and SOHO (SOlar Heliospheric Observatory) probes, NASA’s SDO and STEREO missions (the Solar Dynamics Observatory and Solar Terrestrial Relations Observatory, respectively), and the joint NASA/ESA Ulysses mission. However, most of these spacecraft have focused mainly on the equatorial regions of the Sun, with the notable exception of Ulysses – this probe observed our star at a wide range of latitudes for nearly two decades, until the mission came to an end in 2009.

Despite Ulysses’ insights, this focus on low solar latitudes has left the Sun’s poles relatively unexplored. A lack of imaging data means that scientists must get creative in piecing together pictures of the Sun’s polar regions – as seen here in this artificial image of the solar north pole.

This image extrapolates low-latitude Proba-2 observations of the Sun to reconstruct a view of the star’s pole. While the poles cannot be seen directly, when spacecraft observe the solar atmosphere they gather data on everything along their line of sight, also viewing the atmosphere extending around the disc of the Sun (the apparent glow around the main disc of the Sun, which also extends over the poles). Scientists can use this to infer the appearance of the polar regions. In order to estimate the properties of the solar atmosphere over the poles, they continuously image the main disc of the Sun and take small slivers of data from the outer and upper regions of the star as it rotates, compensating for the fact that the Sun does not rotate at constant speeds at all latitudes. Over time, these small arrays of data can be combined to approximate a view of the pole, as shown in this view. More in-depth information on the process used to create this image can be found here.

Signs of this patchwork approach can be seen in this image, which comprises data from Proba-2’s extreme-ultraviolet SWAP imager. The line across the middle is created due to small changes in the solar atmosphere that occurred over the timeframe of creating this image. This image also shows a bright bulge on the upper-right side of the Sun; this is created by a low-latitude coronal hole rotating around the solar disc. The polar coronal hole region, which can be seen as the dark patch in the centre of the solar disc, is a source of fast solar wind. It is seen here to contain a subtle network of light and dark structures, which may cause variations in solar wind speed.

While such views go a way towards revealing the secrets of the Sun’s poles – such as how waves propagate across our star, and how it may create phenomena such as coronal holes and ejections that go on to influence space weather around the Earth – direct observations of these regions are needed in order to build on past data gathered by Ulysses. ESA’s Solar Orbiter aims to plug this knowledge gap when it launches in 2020. This mission will study the Sun in detail from latitudes high enough to explore its polar regions, also revealing how its magnetic field and particle emissions impact its cosmic environment – including the area of space that we call home.