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By NASA
X-ray: NASA/CXC/SAO/Univ Mexico/S. Estrada-Dorado et al.; Ultraviolet: NASA/JPL; Optical: NASA/ESA/STScI (M. Meixner)/NRAO (T.A. Rector); Infrared: ESO/VISTA/J. Emerson; Image Processing: NASA/CXC/SAO/K. Arcand; A planet may have been destroyed by a white dwarf at the center of a planetary nebula — the first time this has been seen. As described in our latest press release, this would explain a mysterious X-ray signal that astronomers have detected from the Helix Nebula for over 40 years. The Helix is a planetary nebula, a late-stage star like our Sun that has shed its outer layers leaving a small dim star at its center called a white dwarf.
This composite image contains X-rays from Chandra (magenta), optical light data from Hubble (orange, light blue), infrared data from ESO (gold, dark blue), and ultraviolet data from GALEX (purple) of the Helix Nebula. Data from Chandra indicates that this white dwarf has destroyed a very closely orbiting planet.
This artist’s impression shows a planet (left) that has approached too close to a white dwarf (right) and been torn apart by tidal forces from the star. The white dwarf is in the center of a planetary nebula depicted by the blue gas in the background. The planet is part of a planetary system, which includes one planet in the upper left and another in the lower right. The besieged planet could have initially been a considerable distance from the white dwarf but then migrated inwards by interacting with the gravity of other planets in the system.CXC/SAO/M.Weiss An artist’s concept shows a planet (left) that has approached too close to a white dwarf (right) and is being torn apart by tidal forces from the star. The white dwarf is in the center of a planetary nebula depicted by the blue gas in the background. The planet is part of a planetary system, which includes one planet in the upper left and another in the lower right. The besieged planet could have initially been a considerable distance from the white dwarf but then migrated inwards by interacting with the gravity of the other planets in the system.
Eventually debris from the planet will form a disk around the white dwarf and fall onto the star’s surface, creating the mysterious signal in X-rays that astronomers have detected for decades.
Dating back to 1980, X-ray missions, such as the Einstein Observatory and ROSAT telescope, have picked up an unusual reading from the center of the Helix Nebula. They detected highly energetic X-rays coming from the white dwarf at the center of the Helix Nebula named WD 2226-210, located only 650 light-years from Earth. White dwarfs like WD 2226-210 do not typically give off strong X-rays.
In about 5 billion years, our Sun will run out of fuel and expand, possibly engulfing Earth. These end stages of a star’s life can be utterly beautiful as is the case with this planetary nebula called the Helix Nebula.X-ray: NASA/CXC/SAO/Univ Mexico/S. Estrada-Dorado et al.; Ultraviolet: NASA/JPL; Optical: NASA/ESA/STScI (M. Meixner)/NRAO (T.A. Rector); Infrared: ESO/VISTA/J. Emerson; Image Processing: NASA/CXC/SAO/K. Arcand; A new study featuring the data from Chandra and XMM-Newton may finally have settled the question of what is causing these X-rays from WD 2226-210: this X-ray signal could be the debris from a destroyed planet being pulled onto the white dwarf. If confirmed, this would be the first case of a planet seen to be destroyed by the central star in a planetary nebula.
Observations by ROSAT, Chandra, and XMM-Newton between 1992 and 2002 show that the X-ray signal from the white dwarf has remained approximately constant in brightness during that time. The data, however, suggest there may be a subtle, regular change in the X-ray signal every 2.9 hours, providing evidence for the remains of a planet exceptionally close to the white dwarf.
Previously scientists determined that a Neptune-sized planet is in a very close orbit around the white dwarf — completing one revolution in less than three days. The researchers in this latest study conclude that there could have been a planet like Jupiter even closer to the star. The besieged planet could have initially been a considerable distance from the white dwarf but then migrated inwards by interacting with the gravity of other planets in the system. Once it approached close enough to the white dwarf the gravity of the star would have partially or completely torn the planet apart.
WD 2226-210 has some similarities in X-ray behavior to two other white dwarfs that are not inside planetary nebulas. One is possibly pulling material away from a planet companion, but in a more sedate fashion without the planet being quickly destroyed. The other white dwarf is likely dragging material from the vestiges of a planet onto its surface. These three white dwarfs may constitute a new class of variable, or changing, object.
A paper describing these results appears in The Monthly Notices of the Royal Astronomical Society and is available online. The authors of the paper are Sandino Estrada-Dorado (National Autonomous University of Mexico), Martin Guerrero (The Institute of Astrophysics of Andalusia in Spain), Jesús Toala (National Autonomous University of Mexico), Ricardo Maldonado (National Autonomous University of Mexico), Veronica Lora (National Autonomous University of Mexico), Diego Alejandro Vasquez-Torres (National Autonomous University of Mexico), and You-Hua Chu (Academia Sinica in Taiwan).
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory.
Learn more about the Chandra X-ray Observatory and its mission here:
https://www.nasa.gov/chandra
https://chandra.si.edu
Visual Description
This release features two images; a composite image of the Helix Nebula, and an artist’s rendering of a planet’s destruction, which may be occurring in the nebula’s core.
The Helix Nebula is a cloud of gas ejected by a dying star, known as a white dwarf. In the composite image, the cloud of gas strongly resembles a creature’s eye. Here, a hazy blue cloud is surrounded by misty, concentric rings of pale yellow, rose pink, and blood orange. Each ring appears dusted with flecks of gold, particularly the outer edges of the eye-shape.
The entire image is speckled with glowing dots in blues, whites, yellows, and purples. At the center of the hazy blue gas cloud, a box has been drawn around some of these dots including a bright white dot with a pink outer ring, and a smaller white dot. The scene which may be unfolding inside this box has been magnified in the artist’s rendering.
The artist’s digital rendering shows a possible cause of the large white dot with the pink outer ring. A brilliant white circle near our upper right shows a white dwarf, the ember of a dying star. At our lower left, in the relative foreground of the rendering, is what remains of a planet. Here, the planet resembles a giant boulder shedding thousands of smaller rocks. These rocks flow off the planet’s surface, pulled back toward the white dwarf in a long, swooping tail. Glowing orange fault lines mar the surface of the crumbling planet. In our upper left and lower right, inside the hazy blue clouds which blanket the rendering, are two other, more distant planets. After the rocks from the planet start striking the surface of the white dwarf, X-rays should be produced.
News Media Contact
Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Lane Figueroa
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
lane.e.figueroa@nasa.gov
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By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA marked a key milestone Feb. 18 with installation of RS-25 engine No. E20001, the first new production engine to help power the SLS (Space Launch System) rocket on future Artemis missions to the Moon.
The engine, built by lead SLS engines contractor L3Harris (formerly Aerojet Rocketdyne), was installed on the Fred Haise Test Stand in preparation for acceptance testing next month. It represents the first of 24 new flight engines being built for missions, beginning with Artemis V.
Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin Teams at NASA’s Stennis Space Center deliver, lift, and install the first new production RS-25 engine on the Fred Haise Test Stand on Feb. 18.NASA/Danny Nowlin The NASA Stennis test team will conduct a full-duration, 500-second hot fire, providing critical performance data to certify the engine for use on a future mission. During missions to the Moon, RS-25 engines fire for about 500 seconds and up to the 111% power level to help launch SLS, with the Orion spacecraft, into orbit.
The engine arrived at the test stand from the L3Harris Engine Assembly Facility on the engine transport trailer before being lifted onto the vertical engine installer (VEI) on the west side deck. After rolling the engine into the stand, the team used the VEI to raise and secure it in place.
The upcoming acceptance test follows two certification test series that helped verify the new engine production process and components meet all performance requirements. Four RS-25 engines help launch SLS, producing up to 2 million pounds of combined thrust.
All RS-25 engines for Artemis missions are tested and proven flightworthy at NASA Stennis prior to use. RS-25 tests are conducted by a team of operators from NASA, L3Harris, and Syncom Space Services, prime contractor for site facilities and operations.
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By NASA
5 Min Read Planetary Alignments and Planet Parades
A sky chart showing Mars, Jupiter, Saturn, and Venus in a “planet parade.” Credits:
NASA/JPL-Caltech On most nights, weather permitting, you can spot at least one bright planet in the night sky. While two or three planets are commonly visible in the hours around sunset, occasionally four or five bright planets can be seen simultaneously with the naked eye. These events, often called “planet parades” or “planetary alignments,” can generate significant public interest. Though not exceedingly rare, they’re worth observing since they don’t happen every year.
Why Planets Appear Along a Line in The Sky
“Planet parade” isn’t a technical term in astronomy, and “planetary alignment” can refer to several different phenomena. As the planets of our solar system orbit the Sun, they occasionally line up in space in events called oppositions and conjunctions. A planetary alignment can also refer to apparent lineups in our sky with other planets, the Moon, or bright stars.
The planets of our solar system always appear along a line on the sky. This line, referred to as the ecliptic, represents the plane in which the planets orbit, seen from our position within the plane itself. NASA/Preston Dyches When it comes to this second type of planetary alignment, it’s important to understand that planets always appear along a line or arc across the sky. This occurs because the planets orbit our Sun in a relatively flat, disc-shaped plane. From Earth, we’re looking into that solar system plane from within. We see the racetrack of the planets from the perspective of one of the racers ourselves. When viewed edge-on, this disc appears as a line, which we call the ecliptic or ecliptic plane.
So, while planet alignment itself isn’t unusual, what makes these events special is the opportunity to observe multiple planets simultaneously with the naked eye.
Will the Planets Actually be Visible?
Before preparing to observe a planet parade, we have to consider how high the planets will appear above the horizon. For most observers to see a planet with the naked eye, it needs to be at least a few degrees above the horizon, and10 degrees or higher is best. This is crucial because Earth’s atmosphere near the ground dims celestial objects as they rise or set. Even bright planets become difficult or impossible to spot when they’re too low, as their light gets scattered and absorbed on its path to your eye. Buildings, trees, and other obstructions often block the view near the horizon as well.
This visibility challenge is particularly notable after sunset or before sunrise, where the sky is still glowing. If a planet appears very low within the sunset glow, it is very difficult to observe.
The Planets You Can See, and Those You Can’t
Five planets are visible without optical aid: Mercury, Venus, Mars, Jupiter, and Saturn. Ancient civilizations recognized these worlds as bright lights that wandered across the starscape, while the background stars remained fixed in place. In fact, the word “planet” comes to us from the Greek word for “wanderer.”
The solar system includes two additional major planets, Uranus and Neptune, plus numerous dwarf planets like Pluto and Ceres. Uranus and Neptune orbit in the dim, cold depths of the outer solar system. Neptune absolutely requires a telescope to observe. While Uranus is technically bright enough to detect with good eyesight, it’s quite faint and requires dark skies and precise knowledge of its location among similarly faint stars, so a telescope is recommended. As we’ll discuss in the next section, planet parades necessarily must be observed in twilight before dawn or after sunset, and this is not a good time to try observing extremely faint objects like Uranus and Neptune.
Thus, claims about rare six- or seven-planet alignments which include Uranus and Neptune should be viewed with the understanding that these two distant planets will not be visible to the unaided eye.
What Makes Multi-Planet Lineups Special
Lineups of four or five planet naked-eye planets with optimal visibility typically occur every few years. Mars, Jupiter, and Saturn are frequently seen in the night sky, but the addition of Venus and Mercury make four- and five-planet lineups particularly noteworthy. Both orbit closer to the Sun than Earth, with smaller, faster orbits than the other planets. Venus is visible for only a couple of months at a time when it reaches its greatest separation from the Sun (called elongation), appearing just after sunset or before sunrise. Mercury, completing its orbit in just 88 days, is visible for only a couple of weeks (or even a few days) at a time just after sunset or just before sunrise.
Planet parades aren’t single-day events, as the planets move too slowly for that. Generally, multi-planet viewing opportunities last for weeks to a month or more. Even five-planet events last for several days as Mercury briefly emerges from and returns to the Sun’s glare.
In summary, while they aren’t once-in-a-lifetime events, planetary parades afford an uncommon opportunity to look up and appreciate our place in our solar system, with diverse worlds arrayed across the sky before our very eyes.
Other Planet Lineups
Other recent and near-future multi-planet viewing opportunities:
January 2016 – Four planets visible at once before sunrise Late April to Late August 2022 – Four planets visible at once before sunrise Mid-June to Early July 2022 – Five planets visible at once before sunrise January to mid-February 2025 – Four planets visible at once after sunset Late August 2025 – Four planets visible at once before sunrise Late October 2028 – Five planets visible at once before sunrise Late February 2034 – Five planets visible at once after sunset (Venus and Mercury challenging to observe) About the January/February 2025 Planet Parade
The current four-planet lineup concludes by mid-February, as Saturn sinks increasingly lower in the sky each night after sunset. By mid-to-late February, Saturn appears less than 10 degrees above the horizon as sunset fades, making it difficult to observe for most people. While Mercury briefly joins Saturn in the post-sunset glow at the end of February, both planets will be too low and faint for most observers to spot.
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By NASA
3 min read
January’s Night Sky Notes: The Red Planet
by Kat Troche of the Astronomical Society of the Pacific
Have you looked up at the night sky this season and noticed a bright object sporting a reddish hue to the left of Orion? This is none other than the planet Mars! January will be an excellent opportunity to spot this planet and some of its details with a medium-sized telescope. Be sure to catch these three events this month.
Martian Retrograde
Mars entered retrograde (or backward movement relative to its usual direction) on December 7, 2024, and will continue throughout January into February 23, 2025. You can track the planet’s progress by sketching or photographing Mars’ position relative to nearby stars. Be consistent with your observations, taking them every few nights or so as the weather permits. You can use free software like Stellarium or Stellarium Web (the browser version) to help you navigate the night as Mars treks around the sky. You can find Mars above the eastern horizon after 8:00 PM local time.
This mid-January chart shows the path of Mars from September 2024 to June 2025 as it enters and then exits in retrograde motion. Mars appears to change its direction of motion in the sky because Earth is passing the slower-moving Mars in its orbit. Stellarium Hide and Seek
On the night of January 13th, you can watch Mars ‘disappear’ behind the Moon during an occultation. An occultation is when one celestial object passes directly in front of another, hiding the background object from view. This can happen with planets and stars in our night sky, depending on the orbit of an object and where you are on Earth, similar to eclipses.
A simulated view of the Moon as Mars begins its occultation on January 13, 2025. Stellarium Depending on where you are within the contiguous United States, you can watch this event with the naked eye, binoculars, or a small telescope. The occultation will happen for over an hour in some parts of the US. You can use websites like Stellarium Web or the Astronomical League’s ‘Moon Occults Mars’ chart to calculate the best time to see this event.
Closer and Closer
As you observe Mars this month to track its retrograde movement, you will notice that it will increase in brightness. This is because Mars will reach opposition by the evening of January 16th. Opposition happens when a planet is directly opposite the Sun, as seen from Earth. You don’t need to be in any specific city to observe this event; you only need clear skies to observe that it gets brighter. It’s also when Mars is closest to Earth, so you’ll see more details in a telescope.
Want a quick and easy way to illustrate what opposition is for Jupiter, Saturn, Mars, or other outer worlds? Follow the instructions on our Toolkit Hack: Illustrating Opposition with Exploring the Solar System page using our Exploring Our Solar System activity!
A mosaic of the Valles Marineris hemisphere of Mars projected into point perspective, a view similar to that which one would see from a spacecraft. The mosaic is composed of 102 Viking Orbiter images of Mars. NASA/JPL-Caltech Mars has fascinated humanity for centuries, with its earliest recorded observations dating back to the Bronze Age. By the 17th century, astronomers were able to identify features of the Martian surface, such as its ice caps and darker regions. Since the 1960s, exploration of the Red Planet has intensified with robotic missions from various space organizations. Currently, NASA has five active missions, including rovers and orbiters, with the future focused on human exploration and habitation. Mars will always fill us with a sense of wonder and adventure as we reach for its soil through initiatives such as the Moon to Mars Architecture and the Mars Sample Return campaign.
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