In the Sky This Week – August 18, 2020

Happy Birthday Amanda!

Today is my youngest daughter Amanda’s 32nd birthday! Amanda is married to Sam Festian, and they have a 6 month old daughter who is adorable, good-natured, and sleeps through the night. When Amanda was a baby… she was adorable! My wife and I comment frequently how lucky Sam and Amanda are to have a baby that very rarely cries; however, Alayanora is starting to vocalize this weird thing I’m calling the “monster growl.” My wife got some baby dresses with stars and constellations on them – three different sizes… so the baby will be able to wear the “same” dress for months as she grows.

Jupiter and Saturn continue to appear in the southern sky during the early morning and predawn hours this week. Keep watching Jupiter  as it slowly gets closer to Saturn over the next couple months.

Jupiter and Saturn appear in the southern sky around midnight near the constellation Sagittarius. and move westward during the early morning hours. Credit: Stellarium / Bob Trembley.

The Pleiades star cluster, Uranus and Mars appear in the eastern sky during the early morning hours this week; I zoomed in to Uranus, and noticed a set of three stars that should help with star-hopping to Uranus. There is another nearby star that appears to be about the same magnitude as Uranus you can star-hop from as well.

The Pleiades, Uranus and Mars appear in the eastern sky during the early morning hours Insert: a close-up of Uranus, showing some stars to help find the planet. Credit: Stellarium / Bob Trembley.

The planet Venus appears on the eastern horizon with the constellation Orion during the predawn hours.

Venus appears near the constellation Orion in the eastern predawn sky this week. Credit: Stellarium / Bob Trembley.

A waxing crescent Moon appears on the southwestern horizon after sunset from August 21-24th.

The Moon is a very thin waning crescent, so thin it’s probably invisible as I write this.

The new Moon occurs on August 19th – the Moon will not be visible at this time.

After August 19th, the Moon will be a waxing crescent – visible toward the southwest in early evening; this is a good time to look for earthshine.

The Moon from 2020-08-18 – 2020-08-24. Visualizations by Ernie Wright / NASA’s Scientific Visualization Studio.

If you click on the Moon image above, or click this link, you will go to NASA’s Moon Phase and Libration, 2020 page – it will show you what the Moon looks like right now. If you click the image on that page, you will download a high-rez TIF image annotated with the names of prominent features – helpful for logging your observations!

Moon News

The Sun is spot-free; the coronal hole at the Sun’s north pole continues to remain open and large; the coronal hole at the south pole is also open, but is smaller than the northern hole, and appears blotchy. Between the equator and the south pole there is a small hole, and a region of coronal loop activity.

The Sun seen in 193 angstroms (extreme ultraviolet) August 17, 2020:

Several prominences and a lot of coronal activity on the Sun’s limb recently; see if you can spot the eclipse in a couple frames in the video below.

The Sun seen in 304 angstroms (extreme ultraviolet) August 17, 2020:

Solar Activity on Facebook – Run by Volunteer NASA/JPL Solar System Ambassador Pamela Shivak

https://www.facebook.com/photo.php?fbid=10223178632795062&set=gm.3458504094160910&type=3&theater&ifg=1

Solar Corona

Solar wind speed is 307.9 km/sec (↑), with a density of 14.7 protons/cm³ (↑↑) at 1340 UT.

Near real-time animation of the corona and solar wind from the Solar & Heliospheric Observatory (SOHO):

Animated LASCO C2 Coronograph showing the solar corona above the Sun’s limb (the white circle). Credit: NASA/JPL-Caltech-SOHO

Sun News

Upcoming Earth-asteroid encounters:

Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Red highlighted entries are asteroids that either pass very close, or very large with high relative velocities to the Earth. Table from SpaceWeather.com

Asteroid News: Close pass of asteroid 2020 QG

On August 170, 2020, the NASA All Sky Fireball Network reported 26 fireballs. 
(18 sporadics, 7 Perseids, 1 Kappa Cygnid)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). Credit: SpaceWeather.com

Fireball News: Bolide over China!

At 22:59 p.m. on August 16, 2020, CMMO Linyi observation station observed a super fireball with a green beginning and a purple red end. The meteor illuminated the whole earth and accompanied with sound. This phenomenon has been observed at several observation stations in Shandong and Jiangsu provinces of China, accompanied by a large number of eyewitness reports, with brightness exceeding – 20 magnitude. Source: SpaceWeather.com

Position of the planets and a couple spacecraft in the inner solar system.

Position of the planets and a couple spacecraft in the inner solar system, 2020-08-18. Credit: NASA Eyes on the Solar System / Bob Trembley.

Position of the planets in the middle solar system:

Position of the planets in the middle solar system, 2020-08-18. Credit: NASA Eyes on the Solar System / Bob Trembley.

Position of the planets, some dwarf planets and some transneptunian objects in the outer solar system:

Position of the planets and some transneptunian objects in the outer solar system, 2020-08-18 (oblique-view). Credit: NASA Eyes on the Solar System / Bob Trembley.

Highlight: Pluto

Now-famous view of Pluto acquired 13 July 2015, and unveiled at the morning briefing on 14 July. Photo: NASA/JHU APL/Southwest Research Institute.

Pluto (minor planet designation: 134340 Pluto) is an icy dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It was the first and the largest Kuiper belt object to be discovered.

Pluto was discovered by Clyde Tombaugh in 1930 and declared to be the ninth planet from the Sun. After 1992, its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt. In 2005, Eris, a dwarf planet in the scattered disc which is 27% more massive than Pluto, was discovered. This led the International Astronomical Union (IAU) to define the term “planet” formally in 2006, during their 26th General Assembly. That definition excluded Pluto and reclassified it as a dwarf planet.

It is the ninth-largest and tenth-most-massive known object directly orbiting the Sun. It is the largest known trans-Neptunian object by volume but is less massive than Eris. Like other Kuiper belt objects, Pluto is primarily made of ice and rock and is relatively small—one-sixth the mass of the Moon and one-third its volume. It has a moderately eccentric and inclined orbit during which it ranges from 30 to 49 astronomical units or AU (4.4–7.4 billion km) from the Sun. This means that Pluto periodically comes closer to the Sun than Neptune, but a stable orbital resonance with Neptune prevents them from colliding. Light from the Sun takes 5.5 hours to reach Pluto at its average distance (39.5 AU). – Wikipedia

There is an lot more about Pluto in this Wikipedia article.

Read more about Pluto on NASA’s Solar System Exploration site: https://solarsystem.nasa.gov/planets/dwarf-planets/pluto/overview/

Pluto’s Moons

Pluto has five known moons: Charon (the largest, with a diameter just over half that of Pluto), Styx, Nix, Kerberos, and Hydra. Pluto and Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body.

The New Horizons spacecraft performed a flyby of Pluto on July 14, 2015, becoming the first ever, and to date only, spacecraft to do so. During its brief flyby, New Horizons made detailed measurements and observations of Pluto and its moons. In September 2016, astronomers announced that the reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be ingredients for the emergence of life, and produced from methane, nitrogen and other gases released from the atmosphere of Pluto and transferred 19,000 km (12,000 mi) to the orbiting moon. – Wikipedia

Family Portrait of Pluto’s Moons: This composite image shows a sliver of Pluto’s large moon, Charon, and all four of Pluto’s small moons, as resolved by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft. All the moons are displayed with a common intensity stretch and spatial scale (see scale bar). Charon is by far the largest of Pluto’s moons, with a diameter of 751 miles (1,212 kilometers). Nix and Hydra have comparable sizes, approximately 25 miles (40 kilometers) across in their longest dimension above. Kerberos and Styx are much smaller and have comparable sizes, roughly 6-7 miles (10-12 kilometers) across in their longest dimension. All four small moons have highly elongated shapes, a characteristic thought to be typical of small bodies in the Kuiper Belt. Credits: NASA/JHUAPL/SwRI

Pluto’s Blue Sky: Pluto’s haze layer shows its blue color in this picture taken by the New Horizons Ralph/Multispectral Visible Imaging Camera (MVIC). The high-altitude haze is thought to be similar in nature to that seen at Saturn’s moon Titan. The source of both hazes likely involves sunlight-initiated chemical reactions of nitrogen and methane, leading to relatively small, soot-like particles (called tholins) that grow as they settle toward the surface. This image was generated by software that combines information from blue, red and near-infrared images to replicate the color a human eye would perceive as closely as possible.
Credits: NASA/JHUAPL/SwRI

NASA’s OSIRIS-REx Asteroid Sample Return Mission

International Space Station

NASA Perseverance Mars Rover

Climate

ex·o·plan·et /ˈeksōˌplanət/, noun: a planet orbiting a star other than the Sun.

Data from the NASA Exoplanet Archive
* Confirmed Planets Discovered by TESS refers to the number planets that have been published in the refereed astronomical literature.
* TESS Project Candidates refers to the total number of transit-like events that appear to be astrophysical in origin, including false positives as identified by the TESS Project.
* TESS Project Candidates Yet To Be Confirmed refers to the number of TESS Project Candidates that have not yet been dispositioned as a Confirmed Planet or False Positive.

Hubble: Beautiful Universe

https://twitter.com/HUBBLE_space/status/1295254238440894464

The Local Stellar Neighborhood

Continuing with my visual tour of nearby stars and their systems, we travel to the Wolf 1061 system, 14.1 light years distant.

Wolf 1061

Wolf 1061 (also known as HIP 80824 and V2306 Ophiuchi) is an M class red dwarf star located about 14.1 light years away in the constellation Ophiuchus. It is the 36th closest known star system to the Sun and has a relatively high proper motion of 1.2 seconds of arc per year. Wolf 1061 does not have any unusual spectroscopic features. The star was first cataloged in 1919 by German astronomer Max Wolf when he published a list of dim stars that had high proper motions. Wolf 1061’s name originates from this list. A seven years study found no evidence of photometric transits and confirms the radial velocity signals are not due to stellar activity. The habitable zone estimate for the system lies between approximately 0.1 and 0.2 AU from the star.

In December 2015, a team of astronomers from the University of New South Wales announced the discovery of three planets orbiting Wolf 1061. The planets were detected by analyzing 10 years of observations of the Wolf 1061 system by the HARPS spectrograph at La Silla Observatory in Chile. The team used archive radial velocity measurements of the star’s spectrum in the HARPS data and, along with 8 years of photometry from the All Sky Automated Survey, discovered two definite planets with orbital periods of around 4.9 and 17.9 days and a very likely third with a period of 67.3 days.

All three planets have masses low enough that they are likely to be rocky planets similar to the inner planets of the Solar System although their actual sizes and densities are currently unknown. However, this information could be determined if the planets happen to transit in front of Wolf 1061 when viewed from Earth. Because all three planets orbit close to the star and have short orbital periods, there is a chance that this will occur. The University of New South Wales team estimated the chances of a transit at around 14% for planet b, 6% for planet c, and 3% for planet d.

One of the planets, Wolf 1061 c, is a super-Earth located near the inner edge of the star’s habitable zone, which conservatively extends from 0.11 to 0.21 AU, or at most from 0.09 to 0.23 AU. It is one of the closest known potentially habitable planets to Earth after Proxima b, Ross 128 b, and Luyten b. The next planet out, Wolf 1061 d, could be marginally habitable depending on its atmosphere’s composition as it orbits just beyond the habitable zone.

In March 2017, another team of astronomers re-analyzed the system using the HARPS spectrograph. They found planets b and c to be quite similar to their originally reported parameters, but found that planet d was more massive and in a larger, more eccentric orbit. The team was also able to find updated parameters for the host star. Their results showed that Wolf 1061 c is slightly smaller, yet closer to the inner edge of the habitable zone. – Wikipedia

Wolf 1061 System Diagram

Wolf 1061 System Diagram. Note: exoplanet surface features are procedurally generated. Credit: SpaceEngine / Bob Trembley

Wolf 1061 Exoplanet Orbital Diagram

Wolf 1061 Exoplanet Orbital Diagram. Credit: SpaceEngine / Bob Trembley

Artist’s Rendering of the Wolf 1061 system

Artistic rendering of red dwarf Wolf 1061 seen form behind exoplanet Wolf 1061 b – the position of Sol is highlighted to the right. Credit: SpaceEngine / Bob Trembley.

Stay safe, be well, and look up!

Apps used for this post:

NASA Eyes on the Solar System: an immersive 3D solar system and space mission simulator – free for the PC /MAC. I maintain the unofficial NASA Eyes Facebook page.
Universe Sandbox: a space simulator that merges real-time gravity, climate, collision, and material interactions to reveal the beauty of our universe and the fragility of our planet. Includes VR support.
SpaceEngine: a free 3D Universe Simulator for Windows. Steam version with VR support available.
Stellarium: a free open source planetarium app for PC/MAC/Linux. It’s a great tool for planning observing sessions. A web-based version of Stellarium is also available.

NOTE: Stellarium version 0.20.2 has been released! Get it free here: http://stellarium.org/en/

Section header image credits:
The Sky – Stellarium / Bob Trembley
Observing Target – Turn Left at Orion / M. Skirvin
The Moon – NASA/JPL-Caltech
The Sun – NASA/JPL-Caltech
Asteroids – NASA/JPL-Caltech
Fireballs – Credited to YouTube
Comets – Comet P/Halley, March 8, 1986, W. Liller
The Solar System – NASA Eyes on the Solar System / Bob Trembley
Spacecraft News – NASA Eyes on the Solar System / Bob Trembley
Exoplanets – Space Engine / Bob Trembley
Light Pollution – NASA’s Black Marble
The Universe – Universe Today