March 12: Monthly Membership Meeting

Photo: The Milky Way by Alan Studt

Milky Way Rising – Photo by Alan Studt

The monthly meeting of the Cuyahoga Astronomical Association will take place Monday, March 12, beginning at 7:30 PM. The evening’s program, “Astrophotography and other Cool Pictures,” will be presented by club members Alan and Gale Studt. The couple will present photos featuring starry night landscapes, panoramas, and star trails blended with earthly landscapes! For the technically-curious, Alan will go over his gear and basic procedures. Plus music and more!

Following the presentation and a brief social break, the club will conduct its membership business meeting.

Our monthly meetings are held on the second Monday of every month (except December) at 7:30 PM at the Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio, in the Cleveland Metroparks.

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Want to see Wednesday’s total lunar eclipse? TV or online are best bet!

Photo: Umbral Shadow Crossing Moon by James Guilford

Umbral Shadow Crossing Moon by James Guilford

A total lunar eclipse will take place in the pre-dawn hours of January 31 but interested viewers in Northeastern Ohio are not well-favored! Weather conditions predicted for Wednesday morning are poor (mostly cloudy, at best) and the timing of the eclipse event itself works against us; at best we would see only a portion of the partial phase before our Moon sets!

Our best bet for watching this total lunar eclipse will be to view it on television or via streaming video. NASA Television and the agency’s website will provide live coverage of the celestial spectacle beginning at 5:30 a.m. EST. Weather permitting, the broadcast will feature views from the varying vantage points of telescopes at NASA’s Armstrong Flight Research Center in Edwards, California; Griffith Observatory in Los Angeles; and the University of Arizona’s Mt. Lemmon SkyCenter Observatory. You can access the live NASA broadcast via some cable television services, or online through NASA’s Moon webpages.

If skies do clear enough to see the Moon from our area, here’s a timetable for significant points in the upcoming eclipse as viewed from the city of Oberlin — the timing would be off only by a few seconds viewed from other areas of Northeastern Ohio.

Timetable of January 31, 2018 Total Lunar Eclipse. Credit:

Timetable of January 31, 2018 Total Lunar Eclipse. Credit:

This eclipse event is getting special attention because it offers the rare coincidence of three lunar events: A “supermoon,” a “blue moon” and a total lunar eclipse at the same time. A “supermoon” occurs when the Moon is closest to Earth in its orbit (at or near perigee) and appears about 14 percent brighter than usual. As the second Full Moon of the month, this Moon is also commonly called a Blue Moon, though it will not be blue in appearance. The “Super Blue Moon” will pass through Earth’s shadow and take on a reddish copper to deep-red tint. The eerie colors of totality seen during lunar eclipses frightened the ancients but delight us!

The last total lunar eclipse occurred Sept. 27-28, 2015. The next total lunar eclipse visible across North America will occur January 21, 2019.

The January 31 eclipse is the third in a series of supermoons in December 2017 and January 2018. Watch the Supermoon Trilogy video.

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Extrasolar star’s turbulent surface imaged

Image: Star π1 Gruis Credit: ESO

Astronomers using ESO’s Very Large Telescope have directly observed granulation patterns on the surface of a star outside the Solar System — the ageing red giant π1 Gruis. This remarkable new image from the PIONIER instrument reveals the convective cells that make up the surface of this huge star. Each cell covers more than a quarter of the star’s diameter and measures about 120 million kilometers across. Image Credit: ESO

Astronomers using ESO’s Very Large Telescope have for the first time directly observed granulation patterns on the surface of a star outside the Solar System — the ageing red giant π1 Gruis. This remarkable new image from the PIONIER instrument reveals the convective cells that make up the surface of this huge star, which has 700 times the diameter of the Sun. Each cell covers more than a quarter of the star’s diameter and measures about 120 million kilometers across. These new results are being published this week in the journal Nature.

Located 530 light-years from Earth in the constellation of Grus (The Crane), π1 Gruis is a cool red giant. It has about the same mass as our Sun, but is 700 times larger and several thousand times as bright. Our Sun will swell to become a similar red giant star in about five billion years.

An international team of astronomers led by Claudia Paladini (ESO) used the PIONIER instrument on European Southern Observatory’s (ESO’s) Very Large Telescope to observe π1 Gruis in greater detail than ever before. They found that the surface of this red giant has just a few convective cells, or granules, that are each about 120 million kilometers across — about a quarter of the star’s diameter. Just one of these granules would extend from the Sun to beyond Venus. The surfaces — known as photospheres — of many giant stars are obscured by dust, which hinders observations. However, in the case of π1 Gruis, although dust is present far from the star, it does not have a significant effect on the new infrared observations.

When π1 Gruis ran out of hydrogen to burn long ago, this ancient star ceased the first stage of its nuclear fusion program. It shrank as it ran out of energy, causing it to heat up to over 100 million degrees. These extreme temperatures fueled the star’s next phase as it began to fuse helium into heavier atoms such as carbon and oxygen. This intensely hot core then expelled the star’s outer layers, causing it to balloon to hundreds of times larger than its original size. The star we see today is a variable red giant. Until now, the surface of one of these stars has never before been imaged in detail.

By comparison, the Sun’s photosphere contains about two million convective cells, with typical diameters of just 1,500 kilometers. The vast size differences in the convective cells of these two stars can be explained in part by their varying surface gravities. π1 Gruis is just 1.5 times the mass of our Sun but much larger, resulting in a much lower surface gravity and just a few, extremely large, granules.

While stars more massive than eight solar masses end their lives in dramatic supernovae explosions, less massive stars like this one gradually expel their outer layers, resulting in beautiful planetary nebulae. Previous studies of π1 Gruis found a shell of material 0.9 light-years away from the central star, thought to have been ejected around 20,000 years ago. This relatively short period in a star’s life lasts just a few tens of thousands of years – compared to the overall lifetime of several billion – and these observations reveal a new method for probing this fleeting red giant phase.

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Upcoming programs….

The Cuyahoga Astronomical Association (CAA) does not hold a General Meeting in December but that doesn’t mean nothing is happening over the winter months! Here are descriptions of programs planned for the CAA’s upcoming meetings:

January 8, 2018
“Journey to Another Solar System!”
Research astronomer and host of WKYC’s “In The Sky” Jay Reynolds will discuss how scientists are working now on a project to send high-speed probes to our nearest star (beyond our own Sun), with data results in less than 40 years of launch!

February 12, 2018
“Parallax: How we measure the distance from us to the stars!”
Club member and self-professed astronomy nerd Tim Campbell will follow Jay Reynolds’s January presentation by showing how through history, humans used cleverness, a basic principle of vision, and a succession of instruments to go from calculating the throwing distance to food to calculating just how far away those little dots in the nighttime sky really are!

March 12, 2018
“Astrophotography and other Cool Pictures”
Club members Alan and Gale Studt will present photos featuring starry night landscapes, panoramas, and star trails blended with earthly landscapes! For the technically curious, Alan will go over his gear and basic procedures. Plus music and more!

May 14, 2018
“The Inflationary Hot Big Bang Theory”
The universe is 13.7 billion years old and our best current understanding of the its origin is called the Big Bang Theory. Gary Kader, Director of the Burrell Memorial Observatory at Baldwin Wallace University, will present a lecture on the science and history of the Big Bang Theory, taking us back to within a trillionth of a second after that beginning.

June 11, 2018
“Telescope Show and Tell”
Tonight various club members will display their favorite telescopes and explain why, how, and “how much!”

CAA’s monthly meetings are held on the second Monday of every month (except December) at 7:30 PM at the Rocky River Nature Center; 24000 Valley Parkway; North Olmsted, Ohio, in the Cleveland Metroparks.

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Discovered: An Earth-sized temperate planet only 11 light-years away

Image: Planet Ross 128 b

This artist’s impression shows the temperate planet Ross 128 b, with its red dwarf parent star in the background. Image Credit: European Southern Observatory

A team working with ESO’s High Accuracy Radial velocity Planet Searcher (HARPS) at the La Silla Observatory in Chile has found that the red dwarf star Ross 128 is orbited by a low-mass exoplanet every 9.9 days. This Earth-sized world is expected to be temperate, with a surface temperature that may also be close to that of the Earth. Ross 128 is the “quietest” nearby star to host such a temperate exoplanet.

“This discovery is based on more than a decade of HARPS intensive monitoring together with state-of-the-art data reduction and analysis techniques. Only HARPS has demonstrated such a precision and it remains the best planet hunter of its kind, 15 years after it began operations,” explains Nicola Astudillo-Defru (Geneva Observatory – University of Geneva, Switzerland), who co-authored the discovery paper.

Red dwarfs are some of the coolest, faintest — and most common — stars in the Universe. This makes them very good targets in the search for exoplanets and so they are increasingly being studied. In fact, lead author Xavier Bonfils (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, Grenoble, France), named their HARPS program The shortcut to happiness, as it is easier to detect small cool siblings of Earth around these stars, than around stars more similar to the Sun.

Many red dwarf stars, including Proxima Centauri, are subject to flares that occasionally bathe their orbiting planets in deadly ultraviolet and X-ray radiation. However, it seems that Ross 128 is a much quieter star, and so its planets may be the closest known comfortable abode for possible life.

Although it is currently 11 light-years from Earth, Ross 128 is moving towards us and is expected to become our nearest stellar neighbor in just 79,000 years — a blink of the eye in cosmic terms. Ross 128 b will by then take the crown from Proxima b and become the closest exoplanet to Earth!

With the data from HARPS, the team found that Ross 128 b orbits 20 times closer than the Earth orbits the Sun. Despite this proximity, Ross 128 b receives only 1.38 times more irradiation than the Earth. As a result, Ross 128 b’s equilibrium temperature is estimated to lie between -60°C and 20°C, thanks to the cool and faint nature of its small red dwarf host star, which has just over half the surface temperature of the Sun. While the scientists involved in this discovery consider Ross 128b to be a temperate planet, uncertainty remains as to whether the planet lies inside, outside, or on the cusp of the habitable zone, where liquid water may exist on a planet’s surface.

Astronomers are now detecting more and more temperate exoplanets, and the next stage will be to study their atmospheres, composition and chemistry in more detail. Vitally, the detection of biomarkers such as oxygen in the very closest exoplanet atmospheres will be a huge next step, which ESO’s Extremely Large Telescope (ELT) is in prime position to take.

“New facilities at ESO will first play a critical role in building the census of Earth-mass planets amenable to characterization. In particular, NIRPS, the infrared arm of HARPS, will boost our efficiency in observing red dwarfs, which emit most of their radiation in the infrared. And then, the ELT will provide the opportunity to observe and characterize a large fraction of these planets,” concludes Xavier Bonfils.

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November 13: Monthly Membership Meeting

Artist's Concept: Nuclear Rocket at Mars. Credit: NASA

Artist’s Concept: Nuclear Rocket at Mars. Credit: NASA

The Cuyahoga Astronomical Association (CAA) will host its monthly meeting at 7:30 PM, Monday, November 13 in the Cleveland Metroparks’ Rocky River Nature Center, North Olmsted. Our speaker, Dr. Stanley Borowski, a Senior Engineer at NASA’s Glenn Research Center, Cleveland, will discuss the use of nuclear rocket engines in space exploration. The program is free and open to the public, no reservations required.

Following the program, the club’s monthly membership meeting will convene.

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First observation of gravitational wave source, a kilonova: the merger of two neutron stars

Photo: Kilonova observed. Credit: NASA and ESA. Acknowledgment: A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), and A. Fruchter and O. Fox (STScI)

On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer both detected gravitational waves from the collision between two neutron stars. Within 12 hours observatories had identified the source of the event within the lenticular galaxy NGC 4993, shown in this image gathered with the NASA/ESA Hubble Space Telescope. The associated stellar flare, a kilonova, is clearly visible in the Hubble observations. This is the first time the optical counterpart of a gravitational wave event was observed. Hubble observed the kilonova gradually fading over the course of six days, as shown in these observations taken in between 22 and 28 August. Credit: NASA and ESA. Acknowledgment: A.J. Levan (U. Warwick), N.R. Tanvir (U. Leicester), and A. Fruchter and O. Fox (STScI)

On 17 August 2017 the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometerboth alerted astronomical observers all over the globe about the detection of a gravitational wave event named GW170817. About two seconds after the detection of the gravitational wave, ESA’s INTEGRAL telescope and NASA’s Fermi Gamma-ray Space Telescope observed a short gamma-ray burst in the same direction.

In the night following the initial discovery, a fleet of telescopes started their hunt to locate the source of the event. Astronomers found it in the lenticular galaxy NGC 4993, about 130 million light-years away. A point of light was shining where nothing was visible before and this set off one of the largest multi-telescope observing campaigns ever — among these telescopes was the NASA/ESA Hubble Space Telescope.

Several different teams of scientists used Hubble over the two weeks following the gravitational wave event alert to observe NGC 4993. Using Hubble’s high-resolution imaging capabilities they managed to get the first observational proof for a kilonova, the visible counterpart of the merging of two extremely dense objects — most likely two neutron stars. Such mergers were first suggested more than 30 years ago but this marks the first firm observation of such an event. The distance to the merger makes the source both the closest gravitational wave event detected so far and also one of the closest gamma-ray burst sources ever seen.

“Once I saw that there had been a trigger from LIGO and Virgo at the same time as a gamma-ray burst I was blown away,” recalls Andrew Levan of the University of Warwick, who led the Hubble team that obtained the first observations. “When I realised that it looked like neutron stars were involved, I was even more amazed. We’ve been waiting a long time for an opportunity like this!”

Hubble captured images of the galaxy in visible and infrared light, witnessing a new bright object within NGC 4993 that was brighter than a nova but fainter than a supernova. The images showed that the object faded noticeably over the six days of the Hubble observations. Using Hubble’s spectroscopic capabilities the teams also found indications of material being ejected by the kilonova as fast as one-fifth of the speed of light.

“It was surprising just how closely the behaviour of the kilonova matched the predictions,” said Nial Tanvir, professor at the University of Leicester and leader of another Hubble observing team. “It looked nothing like known supernovae, which this object could have been, and so confidence was soon very high that this was the real deal.”

Connecting kilonovae and short gamma-ray bursts to neutron star mergers has so far been difficult, but the multitude of detailed observations following the detection of the gravitational wave event GW170817 has now finally verified these connections.

“The spectrum of the kilonova looked exactly like how theoretical physicists had predicted the outcome of the merger of two neutron stars would appear,” says Levan. “It ties this object to the gravitational wave source beyond all reasonable doubt.”

The infrared spectra taken with Hubble also showed several broad bumps and wiggles that signal the formation of some of the heaviest elements in nature. These observations may help solve another long-standing question in astronomy: the origin of heavy chemical elements, like gold and platinum. In the merger of two neutron stars, the conditions appear just right for their production.

The implications of these observations are immense. As Tanvir explains: “This discovery has opened up a new approach to astronomical research, where we combine information from both electromagnetic light and from gravitational waves. We call this multi-messenger astronomy — but until now it has just been a dream!”

Levan concludes: “Now, astronomers won’t just look at the light from an object, as we’ve done for hundreds of years, but also listen to it. Gravitational waves provide us with complementary information from objects which are very hard to study using only electromagnetic waves. So pairing gravitational waves with electromagnetic radiation will help astronomers understand some of the most extreme events in the Universe.”

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