NASA’s James Webb Space Telescope (JWST) has only been operational for just over a year, but this isn’t stopping the world’s biggest space agency from discussing the next big space telescope that could serve as JWST’s successor sometime in the future. Enter the Habitable Worlds Observatory (HWO), which was first proposed as NASA’s next flagship Astrophysics mission during the National Academy of Sciences’ Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020). While its potential technological capabilities include studying exoplanets, stars, galaxies, and a myriad of other celestial objects for life beyond Earth, there’s a long way to go before HWO will be wowing both scientists and the public with breathtaking images and new datasets.Continue reading “Planning is Underway for NASA’s Next Big Flagship Space Telescope”
Spacecraft instruments are highly specialized and can take years to design, build, and test. But a last-minute hack to one of the instruments on the ESA’s Solar Orbiter has allowed the spacecraft to take some difficult observations it would otherwise have been unable to take.
It’s all because of one astronomer and an instrument door.Continue reading “A Last-Minute Addition to the Solar Orbiter Allows it to See More Deeply into the Sun’s Atmosphere”
Detecting exoplanets was frontier science not long ago. But now we’ve found over 5,000 of them, and we expect to find them around almost every star. The next step is to characterize these planets more fully in hopes of finding ones that might support life. Directly imaging them will be part of that effort.
But to do that, astronomers need to block out the light from the planets’ stars. That’s challenging in binary star systems.Continue reading “It’s Already Hard Enough to Block a Single Star’s Light to See its Planets. But Binary Stars? Yikes”
AU Microscopii is a small red dwarf star about 32 light-years away. It’s far too dim for the unaided human eye, but that doesn’t diminish its appeal. The star has at least two exoplanets and hosts a circumstellar debris disk.
It’s also young, only about 23 million years old, and it’s the second-closest pre-main sequence star to Earth. The JWST recently imaged the star and its surroundings and found something surprising.Continue reading “By Blocking the Light From a Star, Webb Reveals the Dusty Disk Surrounding It”
NASA’s next great space telescope should launch no later than 2027. The Nancy Grace Roman Space Telescope is a powerful wide-field infrared telescope that will create panoramic fields of view 100 times greater than Hubble’s. The Roman Telescope has a variety of scientific objectives, and one of its jobs is to complete a census of exoplanets to answer questions around habitability.
A new study shows how the Roman Space Telescope can measure the dust in distant solar systems to help find habitable planets.Continue reading “Dust Might Reveal the Presence of Habitable Planets”
There’s an old adage that says there is ‘nothing new under the Sun…’ but that doesn’t apply when it comes to solar eclipse science.
Beyond just providing an awesome celestial spectacle, astronomers have often taken advantage of the brief moments afforded by solar totality to explore the Sun and its environs. To this end, total solar eclipses have historically offered chances to carry out scientific experiments in the past, and continue to do so today.Continue reading “Modern Solar Eclipse Science: Huge Coronal Mass Ejection Caught in Action”
In the past few decades, the study of extrasolar planets has grown by leaps and bounds, with the confirmation of over 4000 exoplanets. With so many planets available for study, the focus of exoplanet-researchers is shifting from discovery to characterization. In the coming years, new technologies and next-generation telescopes will also enable Direct Imaging studies, which will vastly improve our understanding of exoplanet atmospheres.
To facilitate this process, astronomers will rely on costly technologies like coronagraphs and starshades, which block out the light of a star so any planets orbiting it will become more visible. However, according to a new study by an international team of astronomers and cosmologists, eclipsing binary stars could provide all the shading that’s needed to directly image planets orbiting them.Continue reading “There are Natural Starshades Out There, Which Would Help Astronomers Image Exoplanets”
In the next decade, NASA will be sending some truly impressive facilities to space. These include the next-generation space telescopes like the James Webb Space Telescope (JWST) and the Wide-Field Infrared Space Telescope (WFIRST). Building on the foundation established by Hubble, WFIRST will use its advanced suite of instruments to investigate some of the deepest mysteries of the Universe.
One of these instruments is the coronagraph that will allow the telescope to get a clear look at extra-solar planets. This instrument recently completed a preliminary design review conducted by NASA, a major milestone in its development. This means that the instrument has met all design, schedule and budget requirements, and can now proceed to the next phase in development.Continue reading “WFIRST Gets its Coronagraph, to Block the Light of Stars and Reveal Their Planets”
We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.
In this series we’ll look at the world’s upcoming Super Telescopes:
- The Giant Magellan Telescope
- The Overwhelmingly Large Telescope
- The 30 Meter Telescope
- The European Extremely Large Telescope
- The Large Synoptic Survey Telescope
- The James Webb Space Telescope
- The Wide Field Infrared Survey Telescope
The Wide Field Infrared Survey Telescope (WFIRST)
It’s easy to forget the impact that the Hubble Space Telescope has had on our state of knowledge about the Universe. In fact, that might be the best measurement of its success: We take the Hubble, and all we’ve learned from it, for granted now. But other space telescopes are being developed, including the WFIRST, which will be much more powerful than the Hubble. How far will these telescopes extend our understanding of the Universe?
“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has.” – John Grunsfeld, NASA Science Mission Directorate
The WFIRST might be the true successor to the Hubble, even though the James Webb Space Telescope (JWST) is often touted as such. But it may be incorrect to even call WFIRST a telescope; it’s more accurate to call it an astrophysics observatory. That’s because one of its primary science objectives is to study Dark Energy, that rather mysterious force that drives the expansion of the Universe, and Dark Matter, the difficult-to-detect matter that slows that expansion.
WFIRST will have a 2.4 meter mirror, the same size as the Hubble. But, it will have a camera that will expand the power of that mirror. The Wide Field Instrument is a 288-megapixel multi-band near-infrared camera. Once it’s in operation, it will capture images that are every bit as sharp as those from Hubble. But there is one huge difference: The Wide Field Instrument will capture images that cover over 100 times the sky that Hubble does.
Alongside the Wide Field Instrument, WFIRST will have the Coronagraphic Instrument. The Coronagraphic Instrument will advance the study of exoplanets. It’ll use a system of filters and masks to block out the light from other stars, and hone in on planets orbiting those stars. This will allow very detailed study of the atmospheres of exoplanets, one of the main ways of determining habitability.
WFIRST is slated to be launched in 2025, although it’s too soon to have an exact date. But when it launches, the plan is for WFIRST to travel to the Sun-Earth LaGrange Point 2 (L2.) L2 is a gravitationally balanced point in space where WFIRST can do its work without interruption. The mission is set to last about 6 years.
Probing Dark Energy
“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate at Headquarters in Washington. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”
In a nutshell, there are two proposals for what Dark Energy can be. The first is the cosmological constant, where Dark Energy is uniform throughout the cosmos. The second is what’s known as scalar fields, where the density of Dark Energy can vary in time and space.
Since the 1990s, observations have shown us that the expansion of the Universe is accelerating. That acceleration started about 5 billion years ago. We think that Dark Energy is responsible for that accelerated expansion. By providing such large, detailed images of the cosmos, WFIRST will let astronomers map expansion over time and over large areas. WFIRST will also precisely measure the shapes, positions and distances of millions of galaxies to track the distribution and growth of cosmic structures, including galaxy clusters and the Dark Matter accompanying them. The hope is that this will give us a next level of understanding when it comes to Dark Energy.
If that all sounds too complicated, look at it this way: We know the Universe is expanding, and we know that the expansion is accelerating. We want to know why it’s expanding, and how. We’ve given the name ‘Dark Energy’ to the force that’s driving that expansion, and now we want to know more about it.
Dark Energy and the expansion of the Universe is a huge mystery, and a question that drives cosmologists. (They really want to know how the Universe will end!) But for many of the rest of us, another question is even more compelling: Are we alone in the Universe?
There’ll be no quick answer to that one, but any answer we find begins with studying exoplanets, and that’s something that WFIRST will also excel at.
“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “The Wide-Field Instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”
“The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.” – Paul Hertz, NASA Astrophysics Division
The difficulty in studying exoplanets is that they are all orbiting stars. Stars are so bright they make it impossible to see their planets in any detail. It’s like staring into a lighthouse miles away and trying to study an insect near the lighthouse.
The Coronagraphic Instrument on board WFIRST will excel at blocking out the light of distant stars. It does that with a system of mirrors and masks. This is what makes studying exoplanets possible. Only when the light from the star is dealt with, can the properties of exoplanets be examined.
This will allow detailed measurements of the chemical composition of an exoplanet’s atmosphere. By doing this over thousands of planets, we can begin to understand the formation of planets around different types of stars. There are some limitations to the Coronagraphic Instrument, though.
The Coronagraphic Instrument was kind of a late addition to WFIRST. Some of the other instrumentation on WFIRST isn’t optimized to work with it, so there are some restrictions to its operation. It will only be able to study gas giants, and so-called Super-Earths. These larger planets don’t require as much finesse to study, simply because of their size. Earth-like worlds will likely be beyond the power of the Coronagraphic Instrument.
These limitations are no big deal in the long run. The Coronagraph is actually more of a technology demonstration, and it doesn’t represent the end-game for exoplanet study. Whatever is learned from this instrument will help us in the future. There will be an eventual successor to WFIRST some day, perhaps decades from now, and by that time Coronagraph technology will have advanced a great deal. At that future time, direct snapshots of Earth-like exoplanets may well be possible.
But maybe we won’t have to wait that long.
Starshade To The Rescue?
There is a plan to boost the effectiveness of the Coronagraph on WFIRST that would allow it to image Earth-like planets. It’s called the EXO-S Starshade.
The EXO-S Starshade is a 34m diameter deployable shading system that will block starlight from impairing the function of WFIRST. It would actually be a separate craft, launched separately and sent on its way to rendezvous with WFIRST at L2. It would not be tethered, but would orient itself with WFIRST through a system of cameras and guide lights. In fact, part of the power of the Starshade is that it would be about 40,000 to 50,000 km away from WFIRST.
Dark Energy and Exoplanets are priorities for WFIRST, but there are always other discoveries awaiting better telescopes. It’s not possible to predict everything that we’ll learn from WFIRST. With images as detailed as Hubble’s, but 100 times larger, we’re in for some surprises.
“This mission will survey the universe to find the most interesting objects out there.” – Neil Gehrels, WFIRST Project Scientist
“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”
With all of the Super Telescopes coming on line in the next few years, we can expect some amazing discoveries. In 10 to 20 years time, our knowledge will have advanced considerably. What will we learn about Dark Matter and Dark Energy? What will we know about exoplanet populations?
Right now it seems like we’re just groping towards a better understanding of these things, but with WFIRST and the other Super Telescopes, we’re poised for more purposeful study.
Like coins, most comet have both heads and tails. Occasionally, during a close passage of the Sun, a comet’s head will be greatly diminished yet still retain a classic cometary outline. Rarely are we left with nothing but a tail. How eerie it looks. Like a feather plucked from some cosmic deity floating down from the sky. Welcome to C/2015 D1 SOHO, the comet that almost didn’t make it.
It was discovered on Feb. 18 by Thai amateur astronomer and writer Worachate Boonplod from the comfort of his office while examining photographs taken with the coronagraph on the orbiting Solar and Heliospheric Observatory (SOHO). A coronagraph blocks the fantastically bright Sun with an opaque disk, allowing researchers to study the solar corona as well as the space near the Sun. Boonplod regularly examines real-time SOHO images for comets and has a knack for spotting them; in 2014 alone he discovered or co-discovered 35 comets without so much as putting on a coat.
Learn why there are so many sungrazing comets
Most of them belong to a group called Kreutz sungrazers, the remains of a much larger comet that broke to pieces in the distant past. The vast majority of the sungrazers fritter away to nothing as they’re pounded by the Sun’s gravity and vaporize in its heat. D1 SOHO turned out to be something different – a non-group comet belonging to neither the Kreutz family nor any other known family.
After a perilously close journey only 2.6 million miles from the Sun’s 10,000° surface, D1 SOHO somehow emerged with two thumbs up en route to the evening sky. After an orbit was determined, we published a sky map here at Universe Today encouraging observers to see if and when the comet might first become visible. Although it was last seen at around magnitude +4.5 on Feb. 21 by SOHO, hopes were high the comet might remain bright enough to see with amateur telescopes.
On Wednesday evening Feb. 25, Justin Cowart, a geologist and amateur astronomer from Alto Pass, Illinois figured he’d have a crack at it. Cowart didn’t have much hope after hearing the news that the comet may very well have crumbled apart after the manner of that most famous of disintegrators, Comet ISON . ISON fragmented even before perihelion in late 2013, leaving behind an expanding cloud of exceedingly faint dust.
Cowart set up a camera and tracking mount anyway and waited for clearing in the west after sunset. Comet D1 SOHO was located some 10° above the horizon near the star Theta Piscium in a bright sky. Justin aimed and shot:
“I was able to see stars down to about 6th magnitude in the raw frames, but no comet,” wrote Cowart. “I decided to stack my frames and see if I could do some heavy processing to bring out a faint fuzzy. To my surprise, when DeepSkyStacker spit out the final image I could see a faint cloud near Theta Picsium, right about where the comet expected to be!”
Cowart sent the picture off to astronomer Karl Battams, who maintains the Sungrazer Project website, for his opinion. Battams was optimistic but felt additional confirmation was necessary. Meanwhile, comet observer José Chambo got involved in the discussion and plotted D1’s position on a star atlas (in the blinking photo above) based on a recent orbit calculation. Bingo! The fuzzy streak in Justin’s photo matched the predicted position, making it the first ground-based observation of the new visitor.
Comet D1 SOHO’s orbit is steeply inclined (70°) to the Earth’s orbit. After rounding the Sun, it turned sharply north and now rises higher in the western sky with each passing night for northern hemisphere skywatchers. Pity that the Moon has been a harsh mistress, washing out the sky just as the comet is beginning to gain altitude. These less-than-ideal circumstances haven’t prevented other astrophotographers from capturing the rare sight of a tailless comet. On Feb. 2, Jost Jahn of Amrum, Germany took an even clearer image, confirming Cowart’s results.
To date, there have been no visual observations of D1 SOHO made with binoculars or telescopes, so it’s difficult to say exactly how bright it is. Perhaps magnitude +10? Low altitude, twilight and moonlight as well as the comet’s diffuse appearance have conspired to make it a lofty challenge. That will change soon.
Once the Moon begins its departure from the evening sky on March 6-7, a window of darkness will open. Fortuitously, D1 SOHO will be even higher up and set well after twilight ends. I’m as eager as many of you are to train my scope in its direction and bid both hello and farewell to a comet we’ll never see again.
Here are fresh maps based on the most recent orbit published by the Minor Planet Center. Assuming you wait until after Full Moon, start looking for the comet in big binoculars or a moderate to large telescope right at the end of evening twilight when it’s highest in a dark sky. The comet sets two hours after the end of twilight on March 7th from the central U.S.