Posted on by Shannon Hall

NameExoWorlds, an IAU Worldwide Contest to Name Alien Planets, Continues Controversy

This artist’s view shows an extrasolar planet orbiting a star (the white spot in the right).
This artist’s view shows an extrasolar planet orbiting a star (the white spot in the right). Image Credit: IAU/M. Kornmesser/N. Risinger (skysurvey.org)

The International Astronomical Union has unveiled a worldwide contest, NameExoWorlds, which gives the public a role in naming planets and their host stars beyond the solar system.

It’s the latest chapter in a years-long controversy over how celestial objects, including exoplanets, are classified and named.

Although the IAU has presided over the long process of naming astronomical objects for nearly a century, until last year they didn’t feel the need to include exoplanets on this long list.

As late as March 2013, the IAU’s official word on naming exoplanets was: “The IAU sees no need and has no plan to assign names to these objects at the present stage of our knowledge.” Since there was seemingly going to be so many exoplanets, the IAU saw it too difficult to name them all.

Other organizations, however, such as the SETI institute and the space company Uwingu leapt at the opportunity to engage the public in providing names for exoplanets. Their endeavors have been widely popular with the general public, but generated discussion about how ‘official’ the names would be.

The IAU issued a later statement in April 2014 (which Universe Today covered with vigor) and claimed that these two campaigns had no bearing on the official naming process. By August 2014, the IAU had introduced new rules for naming exoplanets, drastically changing their stance and surprising many.

Now in partnership with Zooniverse, a citizen-science organization, the IAU has drawn up a list of 305 well-characterized exoplanets in 206 solar systems. Starting in September, astronomy organizations can register for the opportunity to select planets for naming.

In October, the IAU plans to ask the registered organizations to vote for the 20 to 30 worlds on the list that they want to name. The exact number will depend on the number of registered groups. In December, those groups can propose names for the worlds that get the most votes. Groups can only propose names in accordance with the following set of rules. A name must be:

—   16 characters or less in length

—   Preferably one word

—   Pronounceable (in some language)

—   Non-offensive

—   Not too similar to an existing name of an astronomical object

Starting in March 2015, the list of proposed names will be put up to an Internet vote. The winners will be validated by the IAU, and announced during a ceremony at the IAU General Assembly in Honolulu in August 2015.

The popular name for a given exoplanet won’t replace the scientific name. But it will carry the IAU seal of approval.

Astronomer Alan Stern, principal investigator of the New Horizons mission to Pluto and CEO of Uwingu told Universe Today’s Senior Editor, Nancy Atkinson, that he was not surprised by the IAU’s new statement. “To my eye though, it’s just more IAU elitism, they can’t seem to get out of their elitist rut thinking they own the Universe.”

“Uwingu’s model is in our view far superior — people can directly name planets around other stars, with no one having to approve the choices,” Stern continued. “With 100 billion plus planets in the galaxy, why bother with committees of elites telling people what they do and don’t approve of?”

If nothing else, the controversy has sparked multiple venues to name exoplanets and more importantly learn about these alien worlds.

Posted on by Nancy Atkinson

Join the Live Discussion: The Hunt for Other Worlds Heats Up

Artist’s impression of a massive asteroid belt in orbit around a star. Earth's water may not have all come from asteroids and comets, so maybe that's true for exoplanets. Credit: NASA-JPL / Caltech / T. Pyle (SSC)
Artist’s impression of a massive asteroid belt in orbit around a star. Earth's water may not have all come from asteroids and comets, so maybe that's true for exoplanets. Credit: NASA-JPL / Caltech / T. Pyle (SSC)

As readers of Universe Today know, exoplanets are one of the hottest topics in astronomy today. In just the past six months, astronomers have announced the discovery of more than 700 planets orbiting other stars, bringing the total to more than 1700. These discoveries include the first Earth-size planet found in what’s called the habitable zone of a star, where liquid water could exist; the oldest known planet that could support life; and the first rocky “mega-Earth,” a planet that’s much like Earth except that it’s 17 times more massive.

On July 9, at 19:00 UTC (3 pm EDT, 12:00 pm PDT), three exoplanet hunters will come together discuss the discovery boom, consider the next steps in the hunt for habitable worlds, and debate whether we’re likely to find alien life in the next decade.

You can watch live (or watch the webcast later) below:

The panel includes MIT’s Zachory Berta-Thompson, Stanford’s Bruce Macintosh and Université de Montréal’s Marie-Eve Naud) will come together discuss the recent discovery boom, consider the next steps in the hunt for habitable worlds, and ponder the odds of finding life on another planet. The discussion will be moderated by journalist Kelen Tuttle.

To submit questions ahead of time or during the webcast, send an email to [email protected] or post on Twitter with hashtag #KavliLive. You can find additional information about the webcast and the Kavli Foundation here.

Posted on by Nancy Atkinson

Nearby Super-Earth is Best Habitable Candidate So Far, Astronomers Say

An artistic representation of Gliese 832 c against a stellar nebula background. A new paper says Gliese 832 might be home to another planet similar to this, but in the habitable zone. Credit: Planetary Habitability Laboratory at the University of Puerto Rico, Arecibo, NASA/Hubble, Stellarium.
An artistic representation of Gliese 832 c against a stellar nebula background. A new paper says Gliese 832 might be home to another planet similar to this, but in the habitable zone. Credit: Planetary Habitability Laboratory at the University of Puerto Rico, Arecibo, NASA/Hubble, Stellarium.

On a clear night, you might be able to spot the red dwarf star Gliese 832 through a backyard telescope, as it is just 16 light years away. Today, astronomers announced the discovery of super-Earth planet orbiting this nearby star and say it might be the best candidate yet for habitable world.

Gliese 832c was spotted by an international team of astronomers, led by Robert A. Wittenmyer from UNSW Australia. They used high-precision radial-velocity data from HARPS-TERRA, the Planet Finder Spectrograph and the UCLES echelle spectrograph. This star is already known to have one additional planet, a cold Jupiter-like planet, Gliese 832 b, discovered in 2009.

Orbital analysis of Gliese 832 c, a potentially habitable world around the nearby red-dwarf star Gliese 832. Gliese 832 c orbits near the inner edge of the conservative habitable zone. Its average equilibrium temperature (253 K) is similar to Earth (255 K) but with large shifts (up to 25K) due to its high eccentricity (assuming a similar 0.3 albedo). Credit: Planetary Habitability Laboratory.
Orbital analysis of Gliese 832 c, a potentially habitable world around the nearby red-dwarf star Gliese 832. Gliese 832 c orbits near the inner edge of the conservative habitable zone. Its average equilibrium temperature (253 K) is similar to Earth (255 K) but with large shifts (up to 25K) due to its high eccentricity (assuming a similar 0.3 albedo). Credit: Planetary Habitability Laboratory.

Since red dwarf stars shine dimly, the habitable zones around these stars would be very close in. Gliese 832c complies with an orbital period of 36 days (it’s orbital companion Gliese 832 b orbits the star in 9.4 years.)

The newly found super-Earth has a mass at least five times that of Earth’s and the astronomers estimate it receives about the same average energy as Earth does from the Sun. “The planet might have Earth-like temperatures, albeit with large seasonal shifts, given a similar terrestrial atmosphere,” says a press release from the Planetary Habitability Laboratory. “A denser atmosphere, something expected for Super-Earths, could easily make this planet too hot for life and a ‘Super-Venus’ instead.”

Using the Earth Similarity Index (ESI) — a measure of how physically similar a planetary mass object is to Earth, where 1 equals the same qualities as Earth — Gliese 832 c has an ESI of 0.81. This is comparable to Gliese 667C c (ESI = 0.84) and Kepler-62 e (ESI = 0.83).

“This makes Gliese 832c one of the top three most Earth-like planets according to the ESI (i.e. with respect to Earth’s stellar flux and mass) and the closest one to Earth of all three, a prime object for follow-up observations. However, other unknowns such as the bulk composition and atmosphere of the planet could make this world quite different to Earth and non-habitable.”

Artistic representation of the potentially habitable exoplanet Gliese 832 c as compared with Earth. Gliese 832 c is represented here as a temperate world covered in clouds. The relative size of the planet in the figure assumes a rocky composition but could be larger for a ice/gas composition. Credit: Planetary Habitability Laboratory.
Artistic representation of the potentially habitable exoplanet Gliese 832 c as compared with Earth. Gliese 832 c is represented here as a temperate world covered in clouds. The relative size of the planet in the figure assumes a rocky composition but could be larger for a ice/gas composition. Credit: Planetary Habitability Laboratory.

In their paper, Wittenmyer and his colleagues noted that while Solar Systems like our own appear — so far — to be rare, the Gliese 832 system is like a scaled-down version of our own Solar System, with an inner potentially Earth-like planet and an outer Jupiter-like giant planet. They added that the giant outer planet may have played a similar dynamical role in the Gliese 832 system to that played by Jupiter in our Solar System.

Certainly, astronomers will be attempting to observe this system further to see if any additional planets can be found.

If you’re interested in trying to see this star, here’s our guide on red dwarf stars that are visible in backyard telescopes.

Posted on by Shannon Hall

A New Mantra: Follow the Methane — May Advance Search for Extraterrestrial Life

Extrasolar planet HD189733b rises from behind its star. Is there methane on this planet? Image Credit: ESA

The search for life is largely limited to the search for water. We look for exoplanets at the correct distances from their stars for water to flow freely on their surfaces, and even scan radiofrequencies in the “water hole” between the 1,420 MHz emission line of neutral hydrogen and the 1,666 MHz hydroxyl line.

When it comes to extraterrestrial life, our mantra has always been to “follow the water.” But now, it seems, astronomers are turning their eyes away from water and toward methane — the simplest organic molecule, also widely accepted to be a sign of potential life.

Astronomers at the University College London (UCL) and the University of New South Wales have created a powerful new methane-based tool to detect extraterrestrial life, more accurately than ever before.

In recent years, more consideration has been given to the possibility that life could develop in other mediums besides water. One of the most interesting possibilities is liquid methane, inspired by the icy moon Titan, where water is as solid as rock and liquid methane runs through the river valleys and into the polar lakes. Titan even has a methane cycle.

Astronomers can detect methane on distant exoplanets by looking at their so-called transmission spectrum. When a planet transits, the star’s light passes through a thin layer of the planet’s atmosphere, which absorbs certain wavelengths of the light. Once the starlight reaches Earth it will be imprinted with the chemical fingerprints of the atmosphere’s composition.

But there’s always been one problem. Astronomers have to match transmission spectra to spectra collected in the laboratory or determined on a supercomputer. And “current models of methane are incomplete, leading to a severe underestimation of methane levels on planets,” said co-author Jonathan Tennyson from UCL in a press release.

So Sergei Yurchenko, Tennyson and colleagues set out to develop a new spectrum for methane. They used supercomputers to calculate about 10 billion lines — 2,000 times bigger than any previous study. And they probed much higher temperatures. The new model may be used to detect the molecule at temperatures above that of Earth, up to 1,500 K.

“We are thrilled to have used this technology to significantly advance beyond previous models available for researchers studying potential life on astronomical objects, and we are eager to see what our new spectrum helps them discover,” said Yurchenko.

The tool has already successfully reproduced the way in which methane absorbs light in brown dwarfs, and helped correct our previous measurements of exoplanets. For example, Yurchenko and colleagues found that the hot Jupiter, HD 189733b, a well-studied exoplanet 63 light-years from Earth, might have 20 times more methane than previously thought.

The paper has been published in the Proceedings of the National Academy of Sciences and may be viewed here.

Posted on by Susie Murph

Carnival of Space #357

Carnival of Space. Image by Jason Major.
Carnival of Space. Image by Jason Major.

Welcome, come in to the 357th Carnival of Space! The carnival is a community of space science and astronomy writers and bloggers, who submit their best work each week for your benefit. I’m Susie Murph, part of the team at Universe Today and now, on to this week’s stories!

We’re going to start off with a double blast from the past, courtesy of CosmoQuest! This week, they’re featuring Stuart Robbins’s blog post from January 13, 2012, titled “Perspective on the Apollo 15 Landing Site.” He explores the region of the Moon that is the current home of the MoonMappers images that YOU are still mapping and exploring today – the Apollo 15 landing site area. It’s a neat place and we can study a lot of things there. Due to a quirk of optics and angles, you can even imagine you’re flying towards it.

Next, we stay with Cosmoquest’s Moon Mappers as they highlight the interesting discovery that the groundbreaking Soviet Lunakhod 2 lunar rover traveled farther than earlier estimated on it’s mission in 1972. Visit MoonMappers at Cosmoquest for more great stories!

Moving through history, we travel over to io9’s Space blog for a history of the American Space Shuttle disasters is a grim reminder of the danger of space travel. Just released is Major Malfunction, a documentary on the two Shuttle catastrophes. Major malfunction is an understatement for the destruction of Space Shuttle Challenger moments after launch in 1986, and the loss of Space Shuttle Columbia during re-entry in 2003.

Next at io9, we visit Mars to view the magnificent Draa, which are ancient landforms created from waves of sand. Check out the article and it’s images here.

We also have another article from io9, which new astronaut Reid Wiseman recounts his first adventurous days in space.

Now we’ll jump over for some gorgeous views from the Chandra X-Ray Observatory! One of their new images is a glorious view of the Whirlpool spiral galaxy which radiates with fantastic points of x-ray light. These image is breath-taking!

Want more gorgeous images? Visit Brownspaceman.com to see his discussion of the Tulip Nebula, which is a composite image which also maps the emissions from this incredible nebula.

Next, we head over to the Meridani Journalfor coverage of a major find in the search for exoplanets. A new world which is more than twice as large as Earth and about 17 times heavier has been discovered, a sort of “mega-Earth” as some have referred to it.

The NextBigFuture Blog lives up to it’s name by bringing us two interesting stories from Elon Musk and his company SpaceX. First, he points out that the key is reusability. Musk said the crewed Dragon is designed to land softly back on Earth and be rapidly turned around for another flight — possibly on the same day. Spacex is aiming for 10 flights without any significant refurbishment for the Dragon v2. The thing that will have to be refurbished is the main heat shield. Further improved heat shield materials [later versions of PICA-X] would mean Spacex could aim for 100 reusable flights.

We then head over to the Urban Astronomer, where recent observations of a very near pair of brown dwarf objects has led to something new: We’re watching the weather on stars themselves!

Finally, we return to Universe Today for some interesting potential missions. First, the B612 Foundation’s privately-funded Sentinel mission, once launched and placed in orbit around the Sun in 2018, will hunt for near-Earth asteroids down to about 140 meters in size using the most advanced infrared imaging technology, without government red tape to hamper the mission. Next, the NASA Innovative Advanced Concepts office announced a dozen far-flung drawing-board proposals that have received $100,000 in Phase 1 funding for the next 9-12 months, one of which is a balloon for exploring Titan. We’re looking forward to hearing about these projects and many others in the coming years.

That’s it for this week’s Carnival! See you all next time!

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, sign up to be a host. Send an email to the above address.

Posted on by Nancy Atkinson

Take a Fly-by Of All the Known Exoplanets

This bubble chart shows the relative sizes of all discovered planets. The color corresponds to the mean equilibrium temperature of the planet. Click to interact on the Open Exoplanet Catalogue website.

Here’s a fun trip through the galaxy, put together by PhD student Tom Hands at the University of Leicester: In the above video, you can fly to of all the known exoplanets (around single stars only), ordered roughly by semi-major axis of largest orbit. Hands said the video is designed to give the viewer an overview of the current distribution of exoplanets.

Hands used data from the Open Exoplanet Catalogue.

Posted on by Jason Major

Kepler Has Found the First Earth-Sized Exoplanet in a Habitable Zone!

Artist's rendering of Kepler-186f (Credit: NASA Ames/SETI Institute/Caltech)

It’s truly a “eureka” moment for Kepler scientists: the first rocky Earth-sized world has been found in a star’s habitable “Goldilocks” zone, the narrow belt where liquid water could readily exist on a planet’s surface without freezing solid or boiling away. And while it’s much too soon to tell if this really is a “twin Earth,” we can now be fairly confident that they do in fact exist.

The newly-confirmed extrasolar planet has been dubbed Kepler-186f. It is the fifth and outermost planet discovered orbiting the red dwarf star Kepler-186, located 490 light-years away. Kepler-186f completes one orbit around its star every 130 days, just within the outer edge of the system’s habitable zone.

The findings were made public today, April 17, during a teleconference hosted by NASA.

“This is the first definitive Earth-sized planet found in the habitable zone around another star,” says lead author Elisa Quintana of the SETI Institute at NASA Ames Research Center. “Finding such planets is a primary goal of the Kepler space telescope. The star is a main-sequence M-dwarf, a very common type.  More than 70 percent of the hundreds of billions of stars in our galaxy are M-dwarfs.”

A visualization of the “unseen” red dwarfs in the night sky. Credit: D. Aguilar & C. Pulliam (CfA)
A visualization of the many “unseen” red dwarfs in the night sky. (CLICK FOR ANIMATION) Credit: D. Aguilar & C. Pulliam (CfA)

Unlike our Sun, which is a G-type yellow dwarf, M-dwarf stars (aka red dwarfs) are much smaller and dimmer. As a result their habitable zones are much more confined. But, being cooler stars, M-dwarfs have long lifespans, offering planets in their habitable zones — like Kepler-186f — potentially plenty of time to develop favorable conditions for life.

In addition, M-dwarfs are the most abundant stars in our galaxy; 7 out of 10 stars in the Milky Way are M-dwarfs, although most can’t be seen by the naked eye. Finding an Earth-sized planet orbiting one relatively nearby has enormous implications in the hunt for extraterrestrial life.

“M dwarfs are the most numerous stars,” said Quintana. “The first signs of other life in the galaxy may well come from planets orbiting an M dwarf.”

Read more: Earthlike Exoplanets Are All Around Us

Still, there are many more conditions on a planet that must be met for it to be actually habitable. But size, composition, and orbital radius are very important first steps.

“Some people call these habitable planets, which of course we have no idea if they are,” said Stephen Kane, an assistant professor of physics and astronomy at San Francisco State University in California. “We simply know that they are in the habitable zone, and that is the best place to start looking for habitable planets.”

Scale comparison of the Kepler-186 system to our inner Solar System (
Scale comparison of the Kepler-186 system and the inner Solar System (NASA Ames/SETI Institute/Caltech)

As far as the planetary system’s age is concerned — which relates to how long life could have potentially had to evolve on Kepler-186f’s surface — that’s hard to determine… especially with M-dwarf stars. Because they are so stable and long-lived, once they’re formed M-dwarfs essentially stay the same throughout their lifetimes.

“We know it’s probably older than a few billion years, but after that it’s very difficult to tell,” BAERI/Ames scientist Tom Barclay told Universe Today. “That’s the problem with M-dwarfs.”

A comparison of the Kepler 186 and Solar systems (NASA/Ames)
A comparison of the Kepler 186 and Solar systems (Presentation slide, NASA/Ames)

The exoplanet was discovered via the transit method used by NASA’s Kepler spacecraft, whereby stars’ brightnesses are continually monitored within a certain field of view. Any dips in luminance reveal the likely presence of a passing planet.

Because of its small size — just slightly over 1 Earth radius — and close proximity to its star, Kepler-186f can’t be observed directly with current telescope technology.

The Gemini North telescope on the summit of Mauna Kea (Gemini Observatory/AURA)
The Gemini North telescope on the summit of Mauna Kea (Gemini Observatory/AURA)

“However, what we can do is eliminate essentially all other possibilities so that the validity of these planets is really the only viable option,” said Steve Howell, Kepler project scientist and a co-author on the paper.

Using the latest advanced imaging capabilities of the Gemini North and Keck II observatories located atop Mauna Kea in Hawaii, astronomers were able to determine that the signals detected by Kepler were from a small orbiting planet and not something else, such as a background or companion star.

“The Keck and Gemini data are two key pieces of this puzzle,” Quintana said. “Without these complementary observations we wouldn’t have been able to confirm this Earth-sized planet.”

Kepler-186f joins the other 20 extrasolar worlds currently listed in the Habitable Exoplanets Catalog, maintained by the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo. To date 961 exoplanets have been confirmed through Kepler observations, with 1,696 total confirmed altogether. (Source)

Artist's conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech
Artist’s conception of the Kepler Space Telescope. Credit: NASA/JPL-Caltech

Read more: Mega Discovery! 715 Alien Planets Confirmed Using a New Trick on Old Kepler Data

Whether Kepler-186f actually resembles Earth or not, this discovery provides more information on the incredible variety of planetary systems to be found even in our little corner of the galaxy.

“The diversity of these exoplanets is one of the most exciting things about the field,” Kane said. “We’re trying to understand how common our solar system is, and the more diversity we see, the more it helps us to understand what the answer to that question really is.”

The SETI Institute’s Allen Telescope Array has surveyed the Kepler-186 system for any potential signals but so far none has been detected. Further observations are planned.

“Kepler-186f is special because we already know that a planet of its size and distance is capable of supporting life.”
– Elisa Quintana, research scientist, SETI Institute

The team’s paper, “An Earth-sized Planet in the Habitable Zone of a Cool Star” by Elisa V. Quintana et al., will be published in the April 18 issue of Science.

Learn more about the Kepler mission here, and read more about this discovery in NASA’s news release here and on the W.M. Keck website here.

Watch some video excerpts of team interviews and data renderings below:

Also, you can download the slides used in the NASA teleconference here.

Sources: San Francisco State University, Gemini Observatory, W.M. Keck Observatory, and SETI news releases

Posted on by Shannon Hall

First Microlensing Detection of a Planet Circling a Brown Dwarf Candidate

This artist's conception could resemble a planetary system in front of a background star. Image Credit: NASA Goddard Space Flight Center / Francis Reddy

When astronomers detect new exoplanets they typically do so using one of two techniques. First, there’s the famous transit technique, which looks for slight dips in light as a planet passes in front of its host star, and second is the radial velocity technique, which senses the motion of a star due to the gravitational pull of its planet.

But then there is gravitational microlensing, the chance magnification of the light from a distant star by the mass of a foreground star and its planets due to the distortion in the fabric of spacetime. While this technique sounds almost improbable, it is so accurate that every detection skips nominating planets as candidates and immediately verifies them as bona-fide worlds.

But without follow-up observations, the microlensing technique struggles with characterizing the incredibly faint host star. Now, a team of international astronomers led by PhD candidate Jennifer Yee from Ohio State University has detected the first microlensing signature, lovingly called MOA-2013-BLG-220Lb, that looks like a confirmed planet orbiting a candidate brown dwarf — an object so faint because it isn’t massive enough to kick-off nuclear fusion in its core.

Matter — no matter how great or small — curves the fabric of spacetime. It can ultimately acts like a lens by curving the background light around it and therefore magnifying the background source. In microlensing, the intervening matter is simply a faint star or perhaps a planetary system.

“As the ‘lens system’ passes in front of a distant, background star, the magnification of that background star changes as a function of time,” Yee told Universe Today. “By measuring the changing magnification of the background star, we can learn about the lensing star and perhaps whether or not it has a planet.”

In a planetary system, the light from the background star will be magnified when the foreground star passes in front of it. If there is a cirlcing planet, there will be an additional cusp in brightness (to a lesser extent but still a tell-tale detection nonetheless).

A sketch of a microlensing signature with a planet in the lens system. Image Credit: NASA / ESA / K. Sahu / STScI
A sketch of a microlensing signature with a planet in the lens system. Image Credit: NASA / ESA / K. Sahu / STScI

At the moment the planetary system transits in front of the background star (and for many years after) we can’t separate the two objects. While the light of the background star may be greatly magnified, its image is distorted because its light merges with the planetary system.

So the microlensing signature cannot tell astronomers anything about the lens system’s star. “It’s out of the ordinary,” Andrew Gould, Yee’s PhD advisor and coauthor on the paper, told Universe Today. “In other techniques people have definitely detected a star and they’re struggling to detect the planet. But microlensing is just the opposite. We detect the planet very clearly, but we can’t detect the host star.”

However, the microlensing signature does give away the lens system’s proper motion — the apparent change in distance over time — as it passes in front of the background star. MOA-2013-BLG-220Lb’s proper motion is extremely high, clocking in at 12.5 milliarcseconds (a distance on the sky that is 2400 times smaller than the size of the full moon) per year. This is roughly three times higher than average.

A high proper motion may be caused by an object that is very close by and is moving slowly or a very distant object moving rapidly. As most stars tend not to move at high speeds, the team assumes the object is relatively close, placing it at a distance of 6,000 light-years.

With a distance fixed, the team is also able to assume a mass for the object. It weighs in below the hydrogen-burning limit and is therefore considered the best brown dwarf candidate microlensing has detected.

“The double-edged sword of microlensing is that no light from the lens star is required,” Yee told Universe Today. “On the one hand, microlensing can find planets around dark or faint objects like brown dwarfs. The flip side is that it’s very difficult to characterize the lens star if its light is not detected.”

Astronomers will have to wait until 2021 to take a second look at the lens system. This time frame is how long we expect it to take before the candidate brown dwarf separates appreciably on the sky from the background star. Once it has done so astronomers will be able to verify whether or not the candidate is truly a brown dwarf.

The paper is available for download here.