Tag Archives: orbits

Scientists Discover Shifting Orbits of Exoplanets – Sciworthy

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Astronomers are particularly interested in understanding how the orbits of planets around other stars evolve. In an idealized model, orbits consist of two uniform spheres revolving around a common center of mass. However, the reality is often more intricate. These deviations from ideal models provide insights into these systems, shedding light on their geometric arrangements in the universe and the potential presence of unseen companion planets.

Recently, a team of astronomers carried out a large-scale survey of Exoplanet TrES-1 b. The researchers selected TrES-1 b to analyze its orbital changes over the last two decades, since its discovery in 2004, because it belongs to the category of exoplanets that are relatively straightforward to observe: hot Jupiters. Hot Jupiters are gas giants similar in size to our solar system’s Jupiter, but they orbit their host stars at much closer distances, sometimes completing a revolution in just a few days. TrES-1 b orbits a star with just under 90% of the mass of our Sun every three days. This brief orbital period enables astronomers to make numerous observations, facilitating the measurement of orbital changes.

The research team initially gathered data on how much light TrES-1 b blocks from Earth’s viewpoint as it transits in front of its host star, referred to as the transit light curve. Most of the optical data originated from ground-based telescopes, inclusive of contributions from citizen scientists. Additionally, they sourced relevant data from the Transiting Exoplanet Survey Satellite, the Hubble Space Telescope, and the Spitzer Space Telescope. This data allowed them to accurately measure the time it took for TrES-1 b to complete its orbit.

They also discovered that another group of astronomers had employed Spitzer’s infrared array camera. Furthermore, they identified four additional studies from 2004 to 2016 that thoroughly measured how the light from TrES-1 b’s host star was affected by its orbital dynamics, specifically through radial velocity. By combining transit light curves, eclipses, and radial velocity data, astronomers gained a holistic understanding of TrES-1 b, which they then compared with statistical models to interpret its long-term behavior.

The research team sought to fit five distinct models to their observations of TrES-1 b to determine which best represented the data. The first model represented a planet with a constant circular orbit, followed by one with a fixed and slightly elliptical orbit, representing an eccentric orbit. The third model employed a circular orbit that gradually decreases in size, termed decaying orbit. The fourth variant implemented a damped and slightly eccentric orbit, while the final model featured a subtly eccentric orbit that also progresses directionally in relation to the star over time, known as precession.

The researchers concluded that, irrespective of the data subsets used, the most plausible explanation for their findings is that TrES-1 b follows an eccentric precessional orbit. They also noted that the damped trajectory model offered a superior fit compared to the steady trajectory models. This implies that while the changes in the exoplanet’s orbit are evident, the data does not support any hypotheses suggesting no actual alterations in its trajectory.

The researchers further elaborated that the rate at which the exoplanet’s orbit is changing indicates the gravitational influence of another planet within the system. They estimated that this hypothetical planet could be no larger than 25% the size of Jupiter and would have an orbital period of no more than 7 days. However, they noted that there was no direct evidence for such a planet in their data, apart from its inferred impact on TrES-1 b. They did discover another exoplanet in the system, termed TrES-1 c, but its wide eccentric orbit is unlikely to account for the changes observed in TrES-1 b’s orbit.

In conclusion, the researchers asserted that a multifaceted methodology to investigate the orbital timings of exoplanets unveils dynamics that may be overlooked by singular observations and models. They advocated for further studies of the long-term behaviors of exoplanets, necessitating extensive monitoring, more precise radial velocity measurements, and complex simulations of multiple celestial bodies within the gravitational system.


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Source: sciworthy.com

Strange vertical orbits of an exoplanet observed around a binary brown dwarf system

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Impression of the artist in the unusual orbit around the brown dwarf of ExoPlanet 2M1510 (AB)B

ESO/L. Calsada

It was first revealed that a pair of rare stars have equally rare companions, exoplanets that rush into orbit vertically.

Astronomers may think they know what the normal thing is about stars and planets, but they say, “But the universe is very diverse.” Amaury Triaud At the University of Birmingham, UK. He and his colleagues unexpectedly discovered evidence of rare constructs while analyzing data collected by a very large Chilean telescope.

The two stars are brown d stars. This means that they are small and very dim because they cannot maintain fusion and are often referred to as failed stars or subseber ral objects. They follow orbit and continue to cover each other when viewed from Earth. Researchers have previously observed only one brown d-star binary.

Triaud and his colleagues carefully analyzed the new binary system to determine the mass of the stars and their movements, and unexpectedly strange signals were found in the data. Ultimately, the only physical scenario that can explain it is that of a planet-sized object orbiting two stars, following an ellipse perpendicular to the star’s orbit.

Triaud says that vertical orbit is not entirely unheard of, but he and his colleagues never expected to see it in this context. “Brown dwarfs are rare. Brown dwarf pairs are rare. Covering a pair of brown dwarfs is even more unusual and faint, making it difficult to measure,” he says. “That was a surprise. In a system that is ideal and not rare in itself, there is this configuration.”

Twenty years ago, such a structure was considered science fiction, but now it has become a scientific fact. Katherine Brandel At Oxford University. “This is a truly beautiful outcome,” she says. Details of the impending orbit of the two stars make a strong claim that this “harmonograph of the sky” is authentic. By studying how they eat each other, we can identify more details about this unique trio’s moves going forward, Blundell says.

Researchers would like to learn more about the exoplanet named 2M1510(AB)B, but can be compared to a fictional tattoo. Star Warsa desert world orbiting two suns. However, the two suns on the 2M1510(AB)B dimming and get exposed to the surface with something similar to the double dose of moonlight.

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Source: www.newscientist.com

A recently discovered tiny moon orbits Neptune and Uranus

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Uranus (left) and Neptune (right) have several more moons

NASA, ESA, Mark Showalter (SETI Institute), Amy Simon (NASA-GSFC), Andrew I. Hsu, Michael H. Wong (University of California, Berkeley)

Astronomers have discovered new moons around Uranus and Neptune for the first time in 10 years. These are the faintest moons ever discovered orbiting a planet, confirming a long-held idea about moons in the outer solar system.

Scott Shepherd from the Carnegie Institution for Science in Washington, D.C., discovered these moons using the Magellan Telescope in Chile and confirmed them using several other large telescopes around the world. “We looked about four times deeper than anyone has ever looked,” Shepherd said. “These satellites are at the edge of our capabilities. They’re just faint, faint points of light.”

Typically, when looking for the moon, you can only get a maximum exposure of about 5 minutes before it becomes overexposed and the moon’s movement renders it useless. Shepard and his team got around this problem by taking many of these five-minute images in quick succession, observing them for hours, and then combining the darker parts of the images. This allowed them to find dim points of light shining from the faintest moons ever discovered, as well as the smallest moons ever discovered around each planet.

The new moon around Uranus is tentatively named S/2023 U1, but will eventually be given the name of a Shakespearean character, along with the planet’s other moons. It is only about 8 kilometers in diameter and orbits once every 680 Earth days.

One of the new moons around Neptune is called S/2021 N1, and we await its official name from Greek mythology. With a diameter of about 14 kilometers, it takes about 27 Earth years to orbit the planet, making it the farthest moon from its host planet ever discovered. This is also the darkest moon ever discovered.

Discovery image of Uranus’ new moon S/2023 U1 with scattered light from Uranus and trails from background stars

Scott S. Shepherd/Carnegie Institution for Science

The brighter, larger moon discovered orbiting Neptune is called S/2002 N5. As its name suggests, this satellite was first discovered more than 20 years before, but was lost before astronomers could confirm its orbit. “The moon can get lost really easily,” Shepard says. “Basically, you need really good weather, your telescopes need to work perfectly, and everything needs to go well to detect these satellites.” If something goes wrong and a planned observation is lost, the satellite moves out of orbit and becomes very difficult to find again.

Each of the three new moons has an orbit similar to the other two moons in its planetary system, and these fellow travelers form small groups that orbit together. This means that each of these groups likely formed together when larger moons broke up during the early solar system chaos.

“Until now, it was unclear whether Uranus and Neptune had a group of exomoons like Jupiter and Saturn,” Shepard said. “We believe these are debris from satellites that were once much larger, but we’ll probably find many more smaller satellites.” Unfortunately, we’re reaching the limits of what we can discover with current technology, he says it may take even longer before these smaller moons are discovered around Uranus and Neptune.

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Source: www.newscientist.com