In the Sky This Week – July 14, 2020

Photos of comet C/2020 F3 NEOWISE have been all over the news recently, and they have been stunning!

https://twitter.com/ThespaceAcad/status/1283037573800169472

I’ve seen several images of comet C/2020 F3 NEOWISE that appear to show the comet’s nucleus fragmenting!

https://twitter.com/AstroBalrog/status/1282997426404708352

Comet NEOWISE appears in the northeastern morning sky from July 14-17th.

Position of comet NEOWISE from July 14-17 in the northeastern morning sky. Credit: Stellarium / Bob Trembley.

Comet NEOWISE appears in the northwestern evening sky before midnight all week.

Position of comet NEOWISE in mid-July in the northwestern evening sky before midnight. Credit: Stellarium / Bob Trembley.

Comet NEOWISE, a crescent Moon, Venus in conjunction with the star Aldebaran, and the Pleiades star cluster appear splashed across the east-northeastern predawn sky for several mornings this week.

A morning sky filled with interesting objects! Comet NEOWISE, a crescent Moon, Venus in conjunction with the star Aldebaran, and the Pleiades star cluster appear splashed across the east-northeastern predawn sky on July 14th. Credit: Stellarium / Bob Trembley.

The Moon moves across the eastern predawn sky before the weekend.

Position of the Moon from July 14-18 in the eastern predawn sky. Credit: Stellarium / Bob Trembley.

The Moon appears in conjunction with Venus and the star Aldebaran in the eastern predawn sky on July 17th.

Conjunction of the Moon, Venus and the star Aldebaran high in the eastern predawn sky on July 17. Credit: Stellarium / Bob Trembley.

Jupiter and Saturn make great late evening and early morning observing targets all week in the southern sky.

Jupiter and Saturn appear in the southern sky during the early morning hours this week. Credit: Stellarium / Bob Trembley.

Mars appears high in the southeastern predawn sky this week.

Mars appears high in the southeastern predawn sky this week. Credit: Stellarium / Bob Trembley.

The Moon is a waning crescent – visible low to the east before sunrise.

The new Moon occurs on Monday July 20th – the Moon is not visible at this time… so it’s a great time to try and get a pic of that comet!

The Moon from 2020-07-14 – 2020-07-20. Visualizations by Ernie Wright / NASA’s Scientific Visualization Studio.

Moon News

https://twitter.com/JimBridenstine/status/1282682166254751745

The Sun has been spotless for 3 days. The northern coronal hole has grown in size, the southern hole remains small; some very small coronal holes pepper the face of the Sun.

The Sun seen in 193 angstroms (extreme ultraviolet)  July 13, 2020:

Wooh! Some ginormous prominences on the Sun’s limb!

The Sun seen in 304 angstroms (extreme ultraviolet) July 13, 2020:

Facebook: SolarActivity – Run by Solar System Ambassador Pamela Skivak

https://www.facebook.com/photo.php?fbid=3236363506425925&set=a.297089300353375&type=3&theater&ifg=1

Solar Corona

Solar wind speed is 370.4 km/sec (↓), with a density of 7.4 protons/cm³ (↑) at 1305 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

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

On July 13, 2020, the NASA All Sky Fireball Network reported 10 fireballs. 
(8 sporadics, 1 July Pegasid, 1 Microscorpiid)

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

Position of the planets and a couple spacecraft in the inner solar system – the Parker Solar Probe flew by Venus last week.

Position of the planets and a couple spacecraft in the inner solar system, 2020-07-14. Credit: NASA Eyes on the Solar System / Bob Trembley.

Position of the planets in the middle solar system – the orbit of asteroid 253 Mathilde is highlighted:

Position of the planets in the middle solar system, 2020-07-14 – the orbit of asteroid 253 Mathilde is highlighted. Credit: NASA Eyes on the Solar System / Bob Trembley.

Position of the planets some transneptunian objects in the outer solar system – the orbit of comet Hale-Bopp is highlighted:

Position of the planets in the outer solar system, 2020-07-14 – the orbit of comet Hale-Bopp is highlighted. Credit: NASA Eyes on the Solar System / Bob Trembley.

Side-view of the orbit of comet Hale-Bopp:

Side-view of the outer solar system showing the orbit of comet Hale-Bopp. Credit: NASA Eyes on the Solar System / Bob Trembley.

Highlight: Jupiter

This full-disc image of Jupiter was taken on 21 April 2014 with Hubble’s Wide Field Camera 3 (WFC3). Credit: NASA, ESA, and A. Simon (Goddard Space Flight Center)

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter is one of the brightest objects visible to the naked eye in the night sky, and has been known to ancient civilizations since before recorded history. It is named after the Roman god Jupiter. When viewed from Earth, Jupiter can be bright enough for its reflected light to cast shadows, and is on average the third-brightest natural object in the night sky after the Moon and Venus.

Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, though helium comprises only about a tenth of the number of molecules. It may also have a rocky core of heavier elements, but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rapid rotation, the planet’s shape is that of an oblate spheroid (it has a slight but noticeable bulge around the equator). The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere. Jupiter has 79 known moons, including the four large Galilean moons discovered by Galileo Galilei in 1610. Ganymede, the largest of these, has a diameter greater than that of the planet Mercury.

Pioneer 10 was the first spacecraft to visit Jupiter, making its closest approach to the planet on December 4, 1973; Pioneer 10 identified plasma in Jupiter’s magnetic field and also found that Jupiter’s magnetic tail was nearly 800 million kilometers long, covering the entire distance to Saturn. Jupiter has been explored on a number of occasions by robotic spacecraft, beginning with the Pioneer and Voyager flyby missions from 1973 to 1979, and later by the Galileo orbiter, which arrived at Jupiter in 1995. In late February 2007, Jupiter was visited by the New Horizons probe, which used Jupiter’s gravity to increase its speed and bend its trajectory en route to Pluto. The latest probe to visit the planet is Juno, which entered into orbit around Jupiter on July 4, 2016. Future targets for exploration in the Jupiter system include the probable ice-covered liquid ocean of its moon Europa. – Wikipedia

There is an absolute TON more about Jupiter in this Wikipedia article.

This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.

The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity. Image Credit: NASA/JPL/DLR

NASA’s Juno Mission is currently orbiting Jupiter.

Read more about Jupiter on NASA’s Solar System Exploration site: https://solarsystem.nasa.gov/planets/jupiter/overview/

OSIRIS-REx Asteroid Sample Return Mission

Illustrating what scientists argue in the paper, this animation demonstrates how top-shape asteroids may have formed. This simulation shows the gravitational reaccumulation of an asteroid parent body (center) following its catastrophic disruption by an impact. The movie begins with a change in perspective to display the initial geometry of the impacted 100-km asteroid, followed by the dispersal of fragments to form separate rubble-pile asteroids. The color of each particle indicates the change in its temperature after impact, with blue being no change and dark red indicated a change of 1000 Kelvin. Credit: NASA/JPL-Caltech.

International Space Station

NASA Perseverance Mars Rover

Hubble Space Telescope

Climate

Kerbal Rocket Challenge – The American Rocketry Challenge partners with Kerbal Space Program!

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.

The Local Stellar Neighborhood

Continuing with my visual tour of nearby stars and their systems, we travel to Teegarden’s Star, 12.58 light years distant. How this star was discovered is an fascinating!

Distance to Teegarden’s Star from Sol; the plane (green) is aligned with the orientation of the plane of the Milky Way galaxy. Credit: SpaceEngine / Bob Trembley.

Teegarden’s Star

Teegarden’s Star /ˈtiːɡɑːrdənz/ (SO J025300.5+165258, 2MASS J02530084+1652532, LSPM J0253+1652) is an M-type red dwarf in the constellation Aries, about 12 light-years from the Solar System. Although it is near Earth it is a dim magnitude 15 and can only be seen through large telescopes. This star was found to have a very large proper motion of about 5 arcseconds per year. Only seven stars with such large proper motions are currently known.

Teegarden’s Star was discovered in 2003 using asteroid-tracking data that had been collected years earlier. This data set is a digital archive created from optical images taken over a five-year period by the Near-Earth Asteroid Tracking (NEAT) program using two 1 m telescopes on Maui, Hawaii. The star is named after the discovery team leader, Bonnard J. Teegarden, an astrophysicist at NASA‘s Goddard Space Flight Center.

Astronomers have long thought it was quite likely that many undiscovered dwarf stars exist within 20 light-years of Earth, because stellar-population surveys show the count of known nearby dwarf stars to be lower than otherwise expected and these stars are dim and easily overlooked. Teegarden’s team thought that these dim stars might be found by data mining some of the huge optical sky survey data sets taken by various programs for other purposes in previous years. So they reexamined the NEAT asteroid tracking data set and found this star. The star was then located on photographic plates from the Palomar Sky Survey taken in 1951. This discovery is significant as the team did not have direct access to any telescopes and did not include professional astronomers at the time of the discovery.

In June 2019, scientists conducting the CARMENES survey at the Calar Alto Observatory announced evidence of two Earth-mass exoplanets orbiting the star within its habitable zone; Teegarden’s Star b orbits inside the optimistic habitable zone, the equivalent in the solar system would be in-between Earth and Venus, whereas Teegarden’s Star c orbits on the outer edge of the conservative habitable zone, similar to Mars.

According to one group of researchers, who were specifically studying this star, both planets could have maintained a dense atmosphere and so therefore there would be a high likelihood that at least one may harbour liquid water. However, another group of scientists, looking at Earth-sized planets in general in the habitable zones of stars, give Teegarden’s b a 3% chance, and Teegarden’s c only a 2% chance, of having even retained an atmosphere. – Wikipedia

Teegarden’s Star System Architecture

Teegarden’s Star System Diagram. Note: exoplanet surface features are procedurally generated. Credit: SpaceEngine / Bob Trembley.

Teegarden’s Star Exoplanet Orbital Diagram

Top-down view of the exoplanet orbits around Teegarden’s Star. Credit: SpaceEngine / Bob Trembley.

For my artist’s renderings for this post, I found a time when the two exoplants were opposite the star from each other; from their surfaces, their sister planet appears as a morning or evening star.

Artist’s Rendering of Exoplanet Teegarden’s b

Artistic rendering of Teegarden’s Star and exoplanet Teegarden’s c seen from the surface of Teegarden’s b. Credit: SpaceEngine / Bob Trembley.

Artist’s Rendering of Exoplanet Teegarden’s c

Artistic rendering of Teegarden’s Star and exoplanet Teegarden’s b seen from just above the surface of Teegarden’s c. 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.

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