In the Sky This Week – January 29, 2019

When I was in Tucson recently, I marveled at the lack of orange sky glow over the city – the night sky was beautiful, and you could see many more stars from within the Tucson city limits, than I can see living 24 miles north of Detroit. See my previous post about Light Pollution.
[show_if device=’desktop’]The Sky | Observing Target | The Moon | The Sun | Asteroids | Fireballs | Comets | Solar System | Spacecraft | Exoplanets | The Universe

Venus continues to move away from Jupiter in the southeastern predawn sky; a waning crescent Moon joins Venus and Jupiter on the mornings of Jan. 29-31.

Several familiar constellations and bright stars appear in the east-southeastern sky after sunset.

Bright stars and constellations in the east-southeastern sky after sunset on Jan. 29, 2019. Credit: Stellarium / Bob Trembley.

Mars appears high in the southwestern sky after sunset all week. Mars is a little getting higher, and drifting a little westward with each day.

Mars is high in the southwestern sky after sunset all week. Credit: Stellarium / Bob Trembley.

I haven’t touched on the sky seen from the southern hemisphere in a while, so here’s the southeastern sky at 11:00 PM as seen from Río Gallegos – far to the south in South America. Crux – the “Southern Cross” is visible, as is Rigel Kentaurus, another name for Alpha Centauri.

In the southern sky: the position of the globular cluster Omega Centauri is highlighted in the southeastern sky as seen from Río Gallegos at 11:00 PM on Jan. 29, 2019. Credit: Stellarium / Bob Trembley.

NGC 5139 – The Omega Centauri Globular Cluster

Br. Guy wanted to show me Omega Centauri while I was in Tucson, but sadly,  it was very low on horizon during the Vatican Observatory Foundation’s 2019 Faith and Astronomy Workshop, and the weather forecast called for clouds most of the week; I’ll have to make sure to suggest having at least one predawn observing session. I’ve heard endless stories about how beautiful Omega Centauri is, so I thought I share it this week.

Omega Centauri (ω Cen or NGC 5139) is a globular cluster in the constellation of Centaurus that was first identified as a non-stellar object by Edmond Halley in 1677. Located at a distance of 15,800 light-years (4,850 pc), it is the largest globular cluster in the Milky Way at a diameter of roughly 150 light-years. It is estimated to contain approximately 10 million stars and a total mass equivalent to 4 million solar masses.

Omega Centauri is so distinctive from the other galactic globular clusters that it is thought to have an alternate origin as the core remnant of a disrupted dwarf galaxy. – Wikipedia

The globular cluster Omega Centauri — with as many as ten million stars — is seen in all its splendor in this image captured with the WFI camera from ESO’s La Silla Observatory. The image shows only the central part of the cluster — about the size of the full moon on the sky (half a degree). North is up, East is to the left. This color image is a composite of B, V and I filtered images. Note that because WFI is equipped with a mosaic detector, there are two small gaps in the image which were filled with lower quality data from the Digitized Sky Survey. Can you find them? NGC 5139 is another designation of this cluster. Credit: ESO

This video is an animation of a globular cluster slowly rotating in 3D. (I wish I could see this in Virtual Reality!)

This video shows a zoom-in to Omega Centauri – I can’t help but think of  Dr David Bowman’s exclamation from 2001 (book) or 2010 (film): “My God—it’s full of stars!”

You might ask “What does a star cluster look like over millions of years?”

And finally, a super-close-up of interior of Omega Centauri:

Colorful Stars Galore Inside Globular Star Cluster Omega Centauri. NASA’s Hubble Space Telescope snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster. Credit: NASA, ESA, and the Hubble SM4 ERO Team

The Moon is an waning crescent – just past third quarter. It will be visible low to the east before sunrise. The new Moon will occur on Feb. 4^th.

The Moon from Jan. 22-28, 2019. Visualizations by Ernie Wright.

The northern coronal hole has opened up a bit since last week – the southern coronal hole is massive! Old sunspot AR 2733 is rotating out of view. SpaceWeather.com says: “A large hole in the sun’s atmosphere is facing Earth and spewing a stream of solar wind in our direction. Extreme ultraviolet telescopes onboard NASA’s Solar Dynamics Observatory photographed the structure on Jan. 28th”

Another Just WOW moment! Last week’s beautiful HUGE prominence was in the lower right – this week, there’s another one in the upper right! This one has a looping bridge between two hedge-row prominences. A couple other prominences can be seen around the Sun’s limb.

The solar wind speed is 360.2 km/sec (⇪), with a density of 5.7 protons/cm³ (⇪).

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

Upcoming Earth-asteroid encounters:

Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com

Annnnnnd I’ve just found another way to suck my time away: looking for 3D models of of asteroids on Sketchfab:

On Jan. 28, 2019, the NASA All Sky Fireball Network reported 13 fireballs.
(13 sporadics)

In this diagram of the inner solar system, all of the fireball orbits from Jan 28, 2019 intersect at a single point–Earth. Source: Spaceweather.com

Comet 38P/Stephan-Oterma. Credit: JPL Small Body Database Browser / Bob Trembley

A bit of comet history:

This is the position of the planets and a couple spacecraft in the solar system.

Parker Solar Probe – Completes Orbit #1

OSIRIS-REx – Imaging Asteroid Bennu

Landsat

Here’s a couple recent examples of Earth science being performed by the Landsat satellites:

TESS now has two!

In other news: I’ve been playing with my VR headset after returning from Tucson, and just found Google Earth VR – where you can “fly like a drone” anywhere on the Earth. Some areas are built up with full 3D models, others are flattened satellite images. My wife launched into Zion Canyon and said “Oh WOW! I can see why Mom said we have to go here!”

Now, if I could “fly like a drone” anywhere over the surfaces of the Moon, Ceres and asteroids Vesta and Bennu – THAT would be super cool!

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.
Stellarium: a free open source planetarium app for PC/MAC/Linux. It’s a great tool for planning observing sessions.

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
The Universe – Universe Today

July 20, 2019 is the 50^th Anniversary of the Apollo 11 landing on the Moon.