Tag: astronomy

TESS releases its first batch of exoplanet candidates

9:59 am

The science team for the U.S.’s exoplanet space telescope TESS this week released its first batch of exoplanet candidates.

TESS scientists released the list so that other astronomers could make an initial determination as to whether these candidates are planets. There are 73 objects in this first batch, including some planets previously known from ground-based searches, says George Ricker, the mission’s principal investigator at the Massachusetts Institute of Technology in Cambridge. Perhaps 5 to 20% of the objects on the list will turn out to be false alarms, he says. Others, if confirmed, will join the ranks of newly discovered exoplanets.

Researchers expect TESS to find as many as 10,000 large planets. But its main goal is to discover and measure the masses of at least 50 small worlds no more than four times the size of Earth.

Meanwhile, Kepler has resumed operations despite being almost out of fuel. The science team there is attempting to squeeze every last ounce of data it can before the spacecraft’s fuel runs out.

1 comment

Arecibo gets upgrade, new funding

9:33 am

Back from the dead: Threatened with closure only last year due to lack of funds, then damaged badly from Hurricane Maria, the Arecibo radio telescope in Puerto Rico has not only obtained a new operational funding from a new partner but also a $6 million upgrade.

The money will help design and build a super-sensitive set of antennas to be installed at the focal point of Arecibo’s dish. The 166 antennas, together part of the phased-array feed to be installed in 2022, are expected to significantly increase Arecibo’s capabilities. The phased-array feed will boost the telescope’s sky survey speed, making it five to six times faster than it is now, and it’ll enable the telescope to look at a larger piece of sky at one time.

…This month’s announced upgrade comes after years of uncertainty about Arecibo’s operations. In September 2017 Hurricane Maria caused about $14 million in damage to the telescope and ancillary buildings, some of which is still being repaired today. The facility lost its 430-megahertz line feed, which was used for atmospheric studies. Pieces of the antenna fell and punctured panels in the primary reflector of the main dish, forcing the replacement of 80–90 of the panels. There was also significant flooding under the primary reflector, which damaged some of the lines and heating facilities. In addition, several pieces of electronic equipment, some imagers, and laser rangers were damaged. Three buildings — a maintenance facility, a heater/transmitter building and a family unit — were also partially or completely destroyed due to rock and tree debris.

The hurricane was only the latest challenge for the observatory, after Arecibo had fought off repeated threats of closure over the previous decade due to NSF funding concerns. The latest situation was resolved last February, when a consortium led by the University of Central Florida took over operation and management of the observatory, significantly lessening the burden on NSF.

While Arecibo is no longer the world’s largest single radio dish, having been topped by China’s FAST radio telescope, it appears at least for now better positioned to do research. China does not yet have the radio astronomers experienced enough to operate its telescope, and so FAST at present is significantly under-utilized.

1 comment

A gas giant exoplanet so hot it resembles a star

8:45 am

Link here. Key quote:

This sweltering exoplanet, located about 620 light-years away from Earth in the constellation Cygnus, is what astronomers call an “ultrahot Jupiter.” KELT-9b is a giant gas world like Jupiter, the largest planet in our solar system. But it’s way bigger — it has three times the mass and twice the diameter of Jupiter — and it orbits extremely close to its hot parent star, KELT-9.

“Ultrahot Jupiter” is an unofficial term for a hot Jupiter exoplanet with temperatures exceeding 3,100 degrees Fahrenheit (1,700 degrees Celsius). They “are so hot that they have some resemblance to being stars even though they’re planets,” Kevin Heng, an astrophysicist at the University of Bern in Switzerland who participated in the study, told Space.com. KELT-9b can reach temperatures of up to 7,800 degrees F (4,300 degrees C).

This record-breaking heat enabled astronomers to detect iron and titanium in KELT-9b’s atmosphere. While researchers have long suspected that these elements are present on some exoplanets — iron is one of the most abundant elements in the universe — it’s difficult to detect them in cooler environments because the atoms are mostly “trapped in other molecules,” Heng said. However, KELT-9b is so hot that the clouds don’t condense in its atmosphere, allowing individual atoms of iron and other metals to fly solo.

Titanium has been found previously in the atmosphere’s of other exoplanets, but only as part of a molecule.

1 comment

Excavation begins on site for Giant Magellan Telescope

9:05 am

Excavation has begun for the site where the Giant Magellan Telescope (GMT) will be built in Chile.

Using a combination of hydraulic drilling and hammering, the excavation work is expected to take about five months to complete. Excavation is a key step towards the construction of the GMT, which is expected to see first light as early as 2024.

The 25-meter diameter GMT, expected to have a final weight of about 1,600 metric tons, will comprise seven 8.4-meter mirrors supported by a steel telescope structure that will be seated on the concrete pier. It will be housed inside a rotating enclosure that will measure 65 meters (~22 stories) tall and 56 meters wide. As well as working on the enclosure and telescope pier foundations, Conpax will excavate a recess in the summit rock for the lower portion of the mirror coating chamber and foundations for a utility building and tunnel on the summit.

Of the next generation of big telescopes, GMT is the closest to completion.

1 comment

No habitable planets for at least one globular cluster

10:17 am

Calculations by astronomers now suggest that the crowded nature of the giant globular cluster Omega Centauri will probably make it impossible for habitable planets to exist there.

In the hunt for habitable exoplanets, Omega Centauri, the largest globular cluster in the Milky Way, seemed like a good place to look. Comprising an estimated 10 million stars, the cluster is nearly 16,000 light years from Earth, making it visible to the naked eye and a relatively close target for observations by the Hubble Space Telescope.

…[T]he cozy nature of stars in Omega Centauri forced the researchers to conclude that [habitable] planetary systems, however compact, cannot exist in the cluster’s core. While our own sun is a comfortable 4.22 light years from its nearest neighbor, the average distance between stars in Omega Centauri’s core is 0.16 light years, meaning they would encounter neighboring stars about once every 1 million years.

“The rate at which stars gravitationally interact with each other would be too high to harbor stable habitable planets,” Deveny said. “Looking at clusters with similar or higher encounter rates to Omega Centauri’s could lead to the same conclusion. So, studying globular clusters with lower encounter rates might lead to a higher probability of finding stable habitable planets.”

Science thus concludes that Isaac Asimov’s classic science fiction short story, Nightfall, is unlikely.

4 comments

Computer simulations suggest solar system was partly shaped by star flyby

9:29 am

The uncertainty of science: New computer simulations now suggest that the solar systems outer regions were shaped by the near approach of another sun-like star billions of years ago.

Susanne Pfalzner and her co-workers suggest that a star was approaching the Sun at an early stage, ‘stealing’ most of the outer material from the Sun’s protoplanetary disk and throwing what was left over into inclined and eccentric orbits. Performing thousands of computer simulations they checked what would happen when a star passes very close-by and perturbs the once larger disk. It turned out that the best fit for today’s outer solar systems comes from a perturbing star which had the same mass as the Sun or somewhat lighter (0.5-1 solar masses) and flew past at approximately 3 times the distance of Neptune.

However, the most surprising thing for the researchers was that a fly-by does not only explain the strange orbits of the objects of the outer solar system, but also gives a natural explanation for several unexplained features of our Solar System, including the mass ratio between Neptune and Uranus, and the existence of two distinct populations of Kuiper Belt objects.

An intriguing result, but to put it mildly it carries a great deal of uncertainty. If true, however, it suggests — as does other research — that our solar system might be somewhat unique. The other research into the solar system’s history suggests we have been traveling through galactic quiet regions for a long time, which helped make things more friendly for the development of life. Together all this work says that in the beginning the solar system was in crowded regions, with its later history then drifting into empty regions.

Thus, the history of our solar system within the galaxy might play a very important part in why we are here.

1 comment

Perseid meteor shower this weekend

10:24 am

The annual Perseid meteor shower upcoming on August 12 is expected to be especially good this year because there will be no moon in the sky.

The Perseid meteors seem to come from a single point, the `radiant’, situated in the constellation Perseus, giving the shower its name. This is however just an effect of perspective, as the meteors move parallel to each other, much like drivers see when driving in heavy rain.

The radiant will be visible from around 10pm and at this time there will be the highest chance of seeing `Earth grazing meteors’. These are meteors that skim the Earth’s atmosphere and so have long, blazing tails.

Observers can expect to see a few tens of meteors per hour, or one every few minutes, once darkness has fallen on 12 August. The number of meteors will peak in the early hours of 13 August, when up to around seventy each hour should be visible.

It is worth it to find a nice dark place and stay up all night at least once in your life to watch this shower. Get a nice camp chair that allows you to lie back, make sure you are dressed comfortably, and sit back and enjoy.

1 comment

Tess captures comet, variable stars, asteroids, and Martian light

8:44 am

During its testing period prior to beginning science operations this month, the exoplanet space telescope TESS spotted in one series of images a comet, a host of variable stars, some asteroids, and even the faint hint of some reflected light from Mars.

Over the course of these tests, TESS took images of C/2018 N1, a comet discovered by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite on June 29. The comet, located about 29 million miles (48 million kilometers) from Earth in the southern constellation Piscis Austrinus, is seen to move across the frame from right to left as it orbits the Sun. The comet’s tail, which consists of gases carried away from the comet by an outflow from the Sun called the solar wind, extends to the top of the frame and gradually pivots as the comet glides across the field of view.

In addition to the comet, the images reveal a treasure trove of other astronomical activity. The stars appear to shift between white and black as a result of image processing. The shift also highlights variable stars — which change brightness either as a result of pulsation, rapid rotation, or by eclipsing binary neighbors. Asteroids in our solar system appear as small white dots moving across the field of view. Towards the end of the video, one can see a faint broad arc of light moving across the middle section of the frame from left to right. This is stray light from Mars, which is located outside the frame. The images were taken when Mars was at its brightest near opposition, or its closest distance, to Earth.

The video that was compiled from these images is embedded below the fold.
» Read more

1 comment

Rogue giant exoplanet or brown dwarf discovered about 20 light years away

5:16 pm

Using the Jansky VLA radio telescope astronomers have detected evidence of rogue giant exoplanet or brown dwarf about 20 light years away

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have made the first radio-telescope detection of a planetary-mass object beyond our Solar System. The object, about a dozen times more massive than Jupiter, is a surprisingly strong magnetic powerhouse and a “rogue,” traveling through space unaccompanied by any parent star.

“This object is right at the boundary between a planet and a brown dwarf, or ‘failed star,’ and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets,” said Melodie Kao, who led this study while a graduate student at Caltech, and is now a Hubble Postdoctoral Fellow at Arizona State University.

The data is not sufficient yet to determine whether this is an exoplanet or a brown dwarf. It is big, and it is floating independent of any other objects, which makes it interesting in of itself.

0 comments

NASA considering more cuts to WFIRST

10:34 am

NASA is considering more cuts to the Wide Field Infrared Space Telescope (WFIRST), presently budgeted at $3.2 billion.

I suspect a contributing factor for these cuts are the problems with the James Webb Space Telescope. NASA has to pay for its new cost overruns and delays, and the fairest place to find those cuts would be from within the astrophysics division.

0 comments

Astronomers discover 10 more Jupiter moons

9:48 am

Worlds without end: Astronomers, while searching for objects in the Kuiper Belt, have discovered 10 more Jupiter moons.

All the newfound moons are small, between about 1 and 3 kilometres across. Seven of them travel in remote orbits more than 20 million kilometres away from Jupiter, and in the opposite direction from the planet’s rotation. That puts them in the category known as retrograde moons.

The eighth moon stands out because it travels in the same region of space as the retrograde moons, but in the opposite direction (that is, in the same direction as Jupiter’s spin). Its orbit is also tilted with respect to those of the retrograde moons. That means it could easily smash into the retrograde moons, pulverizing itself into oblivion. It may be the leftovers of a bigger cosmic collision in the past, Sheppard says.

Jupiter’s moons are named after gods with connections to the mythological Jupiter or Zeus. Sheppard has proposed naming the oddball Valetudo, after one of Jupiter’s descendants, the Roman goddess of hygiene and health.

The ninth and tenth newfound moons orbit closer to Jupiter, moving in the same direction as the planet.

I predict that these are not the last moons of Jupiter to be discovered. As our observing skills improve, more are certain to pop up.

6 comments

Binary asteroid imaged by radio telescopes

10:18 am

Three radio telescopes have successfully imaged the rotation of a binary asteroid, the fourth such binary so far discovered.

On June 21, the asteroid 2017 YE5 made its closest approach to Earth for at least the next 170 years, coming to within 3.7 million miles (6 million kilometers) of Earth, or about 16 times the distance between Earth and the Moon. On June 21 and 22, observations by NASA’s Goldstone Solar System Radar (GSSR) in California showed the first signs that 2017 YE5 could be a binary system. The observations revealed two distinct lobes, but the asteroid’s orientation was such that scientists could not see if the two bodies were separate or joined. Eventually, the two objects rotated to expose a distinct gap between them.

Scientists at the Arecibo Observatory in Puerto Rico had already planned to observe 2017 YE5, and they were alerted by their colleagues at Goldstone of the asteroid’s unique properties. On June 24, the scientists teamed up with researchers at the Green Bank Observatory (GBO) in West Virginia and used the two observatories together in a bi-static radar configuration (in which Arecibo transmits the radar signal and Green Bank receives the return signal). Together, they were able to confirm that 2017 YE5 consists of two separated objects. By June 26, both Goldstone and Arecibo had independently confirmed the asteroid’s binary nature.

The new observations obtained between June 21 and 26 indicate that the two objects revolve around each other once every 20 to 24 hours. This was confirmed with visible-light observations of brightness variations by Brian Warner at the Center for Solar System Studies in Rancho Cucamonga, California.

I have embedded below the fold a short video that includes the radio images showing this rotation. Most cool!
» Read more

1 comment
1 … 85 86 87 88 89 … 188