Tonight’s planned Public Night is CANCELED due to inclement weather conditions and overcast skies expected to continue into late-night.

Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the nearest star to our own Sun, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature possibly suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.

Just over four light-years from the Solar System lies the red dwarf star named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star, in the southern hemisphere constellation of Centaurus, is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.

During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world. This was the Pale Red Dot Campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet.

As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world.

Guillem Anglada-Escudé explains the background to this unique search: “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.”
The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result.

At times Proxima Centauri is approaching Earth at about five kilometers per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about seven million kilometers from Proxima Centauri — only five percent of the Earth-Sun distance.

Guillem Anglada-Escudé comments on the excitement of the last few months: “I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot Campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!”

Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis.

Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun.

Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b’s rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons.

This discovery will be the beginning of extensive further observations, both with current instruments and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project.

Guillem Anglada-Escudé concludes: “Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analog and succeeding has been the experience of a lifetime for all of us. Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next…”

Image: Saturn: August 12, 10:00 PM EDT - Simulated view via Gas Giants app

Saturn: August 12, 10:00 PM EDT – Simulated view via Gas Giants app

UPDATE: Due to mostly-cloudy to overcast skies and recurring scattered thunderstorms, this event has been CANCELED. — JG, 8/12/16, 8:00 PM.

Stephens Memorial Observatory of Hiram College will be open for public observing Friday, August 12, from 9:30 to midnight. Hoping to catch the end of the annual Perseid Meteor Shower, the observatory is hosting its monthly public event on this Friday rather than on Saturday night.

Visitors are invited to bring personal lawn chairs and sit out beneath the stars watching for meteors (mosquito repellent is strongly recommended) until midnight. Via telescope, views of beautiful Saturn, and other objects will also be offered. Saturn’s famous ring system is nicely tilted allowing for excellent viewing, given clear skies.

No reservations are required and there is no admission fee for observatory public nights. Cloudy skies at the starting time cancel the event and, in that case, the observatory will not open.

The Observatory is located on Wakefield Road (Rt. 82) less than a quarter of a mile west of Route 700 in Hiram. There is no parking at the Observatory. Visitors may park on permissible side streets near the Post Office, a short distance east of the observatory.

Two-panel Moon

StephensAstro —  July 18, 2016 — Leave a comment
Photo: Earth's Moon two days short of Full. Photo by James Guilford.

Two-Panel Moon: This photograph of the Moon, our latest experiment using the vintage Cooley Telescope in astrophotography, shows the Moon about two days from Full. Two individual shots were made using a Canon DSLR in place of the telescope’s eyepiece, projecting the lunar image directly upon the camera’s sensor. Exposure: ISO 400, 1/320 second. Adobe Photoshop was used to “photomerge” the individual panels or frames and edit the resulting image. [Click image to enlarge.]

Photo: Moon, Planets, Stars, Observatory. Photo by James Guilford.

Nearly-Full Moon and Stephens Memorial Observatory. In the trees, to right of the Moon, are Saturn (upper), Antares below, and Mars to the right. No, the dome isn’t about to topple – just yet – it’s a fisheye lens effect!
Photo by James Guilford.

 

We hosted a small group of 16 visitors during the July 16 Open Night but enjoyed the event very much; a group of that size is in the not-too-large and not-too-small range that affords easy conversation and sharing of the observatory experience. I the summertime we usually feature Earth’s Moon. Between summer’s late sunsets, and Daylight Saving Time extending twilight by an hour, the Moon reliably shows up even before the sky is dark! Saturday’s experience was no exception.

Photo: Nearly-full Moon. Photo by James Guilford.

Nearly-Full, Gibbous Moon, captured using an iPhone SE held to the eyepiece of the Cooley Telescope at Stephens Memorial Observatory. Photo by James Guilford.

 

We viewed the Moon through the Cooley Telescope’s remarkable optics and were rewarded with exciting detail. Moving along as the sky darkened, we turned our attention to Saturn: the planet’s subtle color and distinctive ring system showed good detail, very good at times. We briefly viewed Mars but the Red Planet is rapidly parting company with Earth and has grown small in the telescope’s eyepiece.

Photo: Earth's Moon, featuring crater Tyco. Photo by James Guilford.

Closer View of the Moon, featuring crater Tyco, using a Canon DSLR and the Cooley Telescope at Stephens Memorial Observatory. Photo by James Guilford.

 

Yes, the “star” of the night was Luna and, once the last visitors departed, we made a few images of our nearest neighbor in space to help illustrate why we love sharing the view!

Image: Saturn and Moons - July 16, 2016 at about 10 PM EDT. Simulated view.

Saturn and Moons – July 16, 2016 at about 10 PM EDT. Simulated view.

Stephens Memorial Observatory of Hiram College will be open for public observing Saturday, July 16, from 9:30 to 11:00 PM. Beautiful ringed Saturn, Earth’s amazing Moon, and hopefully the M4 star cluster in Scorpius will be the featured objects. Mars is rapidly distancing itself from us and will likely be uninteresting in our telescope though we may take a look anyway.

Sky conditions, of course, will determine what we see and even whether we can see anything at all. We will hope for clear skies because Saturn still presents its ring system at an excellent tilt for viewing!

No reservations are required and there is no admission fee for observatory public nights. Cloudy skies at the starting time cancel the event and, in that case, the observatory will not open.

The Observatory is located on Wakefield Road (Rt. 82) less than a quarter of a mile west of Route 700 in Hiram.

There is no parking at the Observatory. Visitors may park on permissible side streets near the Post Office, a short distance east of the observatory. DO NOT park on nearby Peckham Avenue; parking is prohibited there and violators may be ticketed!

Image: This illustration depicts NASA's Juno spacecraft at Jupiter, with its solar arrays and main antenna pointed toward the distant sun and Earth. Image Credit: NASA/JPL-Caltech

This illustration depicts NASA’s Juno spacecraft at Jupiter, with its solar arrays and main antenna pointed toward the distant sun and Earth. Image Credit: NASA/JPL-Caltech

 

NASA’s Juno mission, launched nearly five years ago, will soon reach its final destination: the most massive planet in our solar system, Jupiter. On the evening of July 4, at roughly 9 PM PDT (12 AM EDT, July 5), the spacecraft will complete a burn of its main engine, placing it in orbit around the king of planets.

During Juno’s orbit-insertion phase, or JOI, the spacecraft will perform a series of steps in preparation for a main engine burn that will guide it into orbit. At 9:16 PM EDT (July 4), Juno will begin to turn slowly away from the sun and toward its orbit-insertion attitude. Then 72 minutes later, it will make a faster turn into the orbit-insertion attitude.

At 10:41 PM EDT, Juno switches to its low-gain antenna. Fine-tune adjustments are then made to the spacecraft’s attitude. Twenty-two minutes before the main engine burn, at 10:56 PM, the spacecraft spins up from two to five revolutions per minute (RPM) to help stabilize it for the orbit insertion burn.

At 11:18 PM, Juno’s 35-minute main-engine burn will begin. This will slow it enough to be captured by the giant planet’s gravity. The burn will impart a mean change in velocity of 1,212 MPH (542 meters a second) on the spacecraft. It is performed in view of Earth, allowing its progress to be monitored by the mission teams at NASA’s Jet Propulsion Laboratory in Pasadena, California, and Lockheed Martin Space Systems in Denver, via signal reception by Deep Space Network (DSN) antennas in Goldstone, California, and Canberra, Australia.

After the main engine burn early July 5 (Eastern Daylight Time), Juno will be in orbit around Jupiter. The spacecraft will spin down from five to two RPM, turn back toward the sun, and ultimately transmit telemetry via its high-gain antenna. At Jupiter’s current distance of 536.9 million miles from Earth, radio signals will take about 48 minutes to reach the DSN.

Juno starts its tour of Jupiter in a 53.5-day orbit. The spacecraft saves fuel by executing a burn that places it in a capture orbit with a 53.5-day orbit instead of going directly for the 14-day orbit that will occur during the mission’s primary science collection period. The 14-day science orbit phase will begin after the final burn of the mission for Juno’s main engine on October 19.

JPL manages the Juno mission for NASA. The mission’s principal investigator is Scott Bolton of Southwest Research Institute in San Antonio. The mission is part of NASA’s New Frontiers Program, managed at the agency’s Marshall Space Flight Center in Huntsville, Alabama, for NASA’s Science Mission Directorate. Lockheed Martin Space Systems in Denver built the spacecraft.

Learn more about the June mission, and get an up-to-date schedule of events, at:

http://www.nasa.gov/juno

https://solarsystem.nasa.gov/planets/jupiter/junotoolkit