Posted on by Nancy Atkinson

The Solar Dynamics Observatory Soars to Study the Sun

The Atlas V rocket carrying SDO roars off the launchpad. Credit: Nancy Atkinson

The Solar Dynamics Observatory launched successfully – and beautifully – Thursday morning from Cape Canaveral Launch Complex 41 to begin a 5-year mission that will provide streaming, high-definition views of our sun. It was the 100th launch of the Atlas/Centaur combo, and was a gorgeous sight as it roared and soared into the blue Florida sky. “It was great; a beautiful launch,” said Dean Pesnell, SDO Project Scientist, immediately after the launch. “The rocket rises so slowly off the pad — it is wonderful to see. This is third Atlas launch I’ve seen and this is the best one so far.”

Amazingly, viewers here at Kennedy Space Center saw the Atlas rocket fly close to a sundog just as the spacecraft reached Max-Q, creating a ripple effect around the spacecraft. “We saw this sundog come out and SDO flew right through it. Then the sun dog disappeared,” said Pesnell. “This may be the first time we’ve sent a probe through a sundog, and people will be studying this, so already we are learning things about our atmosphere from SDO.”

See this amazing video shot by a 13-year-old girl in attendance at the KSC VIP site that shows the sundog and shockwave. (as noted by Jon Hanford in the comments).

Today’s countdown was extremely smooth as the high winds that thwarted Wednesday’s launch attempt calmed as the opening of the launch window approached. After counting down to the planned T-4 minute hold, launch managers proceeded directly to launch at the beginning of the window at 10:23 a.m. EST.

Project Scientist Dean Pesnell describing the launch. Image: Nancy Atkinson

“I was a little worried about the clouds coming in,” said Tom Woods, Principal Investigator for the EVE instrument on SDO, the EUV Variability Experiment, which will be studying the extreme ultraviolet radiation of the Sun. “But we were very excited to see SDO launch today, as otherwise it would have been a 10-day delay until the next attempt. It was a wonderful launch!”

“It was so beautiful,” said Lika Guhathakurta, SDO program scientist immediately following the launch as we walked together back to the press building. “I can still feel the rumbling in my stomach!”

SDO science team celebrates after the launch: Dean Pesnell, Jennifer Rumburg, Chris St. Cyr, and Lika Guhathakurta. Image: Nancy Atkinson

Called the “Crown Jewel” of NASA’s fleet of solar observatories, SDO is a technologically advanced spacecraft that will take images of the sun every 0.75 seconds and daily send back about 1.5 terabytes of data to Earth — the equivalent of downloading 380 full-length movies every day.

SDO launch. Credit: Nancy Atkinson

“We’re going to be able to better understand the Sun as a star,” said Guathakurta, “but SDO will also give us a comprehensive view of how it interacts with the Earth and everything else in the solar system.

The sun’s dynamic processes affect everyone and everything on Earth. SDO will explore activity on the sun that can disable satellites, cause power grid failures, and disrupt GPS communications. SDO also will provide a better understanding of the role the sun plays in Earth’s atmospheric chemistry and climate.

Vapor trail from the Atlas rocket after the SDO launch. Image: Nancy Atkinson

A contrail from the launch appeared only in the region of Earth’s atmosphere where conditions were right for cloud formation. “There weren’t any clouds there, but we provided the very fine particles so that a contrail cloud appeared,” said Pesnell.

A later update confirmed that SDO separated from the Centaur and the spacecraft’s solar arrays deployed on time and correctly, and are now generating power.

Here’s the video of the launch from NASA TV:

Posted on by Nancy Atkinson

SDO Launch Scrub; Try Again Tomorrow

SDO on the launchpad. Credit: Nancy Atkinson

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Note: Nancy Atkinson is at Kennedy Space Center to cover SDO and the STS-130 shuttle mission

Scrub! High winds kept the Solar Dynamics Observatory on the ground for today, but the launch team will try again Thursday (Feb. 11) at 10:26 a.m. EST (15:26 GMT). Weather is 60% go for tomorrow, and winds will be down to about 16 knots but cloud cover may be an issue. Today, winds consistently peaked well above the constraint speed of 20 knots – often well into the 30’s. The winds here at the press site were equally strong, and combined with cool weather, kept most people indoors until the launch team gave the go-ahead.

Winds were predicted to decrease later in the day, so the launch team pushed back the countdown as far into the launch window as possible. Originally slated for a 10:26 a.m. EST launch, they first moved it ahead 30 minutes to 10:56, and then to 11:26, leaving just the built-in hold at T-4 minutes in the countdown, — and more importantly, leaving only four minutes for a possible attempt. The count was able to pick up when the weather officer gave the go-ahead, but as soon as the countdown restarted, the count was automatically stopped because the wind loads had risen again.

The scrub was a disappointment for the SDO team, which has had repeated delays in their timeline leading up to launch. But now SDO and the Atlas V rocket can launch any day that the weather allows, so we’ll be back again tomorrow for another try!

You can follow my updates on Twitter (@Nancy_A) for live, real-time updates. I’ll also be reporting live Thursday morning on AstronomyFM, a 24-hour internet radio dedicated to astronomy and space exploration.

Posted on by Ken Kremer

NASA Sun Probe rolled to Pad; 10 hours to Blast off

Launch Complex 41: Atlas rocket was rolled from VIF at left to pad at right on Feb 9, 2010. Credit: Ken Kremer

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(Editor’s Note: Ken Kremer is at the Kennedy Space Center for Universe Today covering the launch of SDO and Endeavour.)

NASA’s nearly $1 Billion hi tech sun probe, the Solar Dynamics Observatory or SDO, was rolled out today (Feb 9) to Launch Pad 41 on a rainy day here in Florida at 1 day from blast off. SDO will be carried aloft atop an Atlas V rocket at 10:26 AM EST on Feb 10 at Cape Canaveral Air Force Station. The launch window extends for 1 hour. The current weather prediction is only 40% “GO”. The primary concerns for launch day are ground winds with gusts and thick clouds.

NASA’s SDO sun explorer is encapsulated inside 4 meter payload fairing and is bolted atop Centaur Upper Stage of Atlas V rocket at Launch Complex 41. Umbilical lines at right carry cryogenic propellants, electrical power and purge gases. Credit: Ken Kremer
At the Kennedy Space Center, I was thrilled to watch the rocket rollout to the pad this morning as part of a NASA Media event along with Universe Today Senior Editor Nancy Atkinson. We were accompanied by a group of SDO managers and science investigators from across the country. The rollout started from inside the 30 story gantry known as the VIF, or Vertical Integration Facility, and ended at the launch pad. It took approximately 35 minutes for the twin “trackmobiles” to push the Atlas rocket about 1800 ft along railroad tracks.

Atlas V booster is 12.5 ft in diameter and 106.5 ft in length. Centaur Upper Stage is 10 ft in diameter and 41.5 ft long. SDO payload fairing is 14 ft in diameter. Total Vehicle height is about 189 ft. Credit: Ken Kremer
This afternoon I traveled directly inside the highly restricted security zone which surrounds Launch Complex 41 for a photo shoot to observe the assembled Atlas V rocket and SDO spacecraft directly at the pad. Fantastic experience despite the rainstorm.

SDO, Atlas V and Ken in ditch below rocket less than 24 hours from blast off. Credit: Ken Kremer

SDO project scientist Dean Pesnell told me in an interview today that “SDO will acquire movies of the entire surface of the Sun on a 24/7 basis with 10 times greater resolution than High Definition. That’s about equivalent in size to an IMAX movie”. The three science instruments will collect a staggering 1.5 terabytes of data per day which is equivalent to downloading 500,000 songs. The data will be beamed back continuously to two dedicated ground stations in New Mexico which were specially constructed for SDO. There are no on board recorders due to the huge volume of data.

“It’s perfect timing to launch and study the sun as it starts the rise to a solar maximum,” according to Pesnell. “The sun patiently waited for us to be ready to launch as we waited for a launch opportunity. After a long period of inactivity, Sun spots recently started appearing at the North Pole. And they also just started at the South Pole”.

“SDO was conceived by the scientists around 1996 and formally approved by NASA in 2002”, Prof. Phillip Scherrer said to me. He is the Principal Investigator for the Helioseismic and Magnetic Imager (HMI) instrument.

“The primary mission phase will last 5 years and hopefully extend out to 10 and perhaps even longer. The longevity depends on the health of the science instruments. Remember SOHO was projected to last 2 years and has now operated for over 15 years ! “

HMI will study the origin of solar variability and attempt to characterize and understand the Sun’s interior and magnetic activity.

Both HMI, and the Atmospheric Imaging Assembly, or AIA, will allow scientists to see the entire disc of the sun in very high resolution — 4,096 by 4,096 mm CCDs. In comparison, a standard digital camera uses a 7.176 by 5.329 mm CCD sensor.

AIA also will image the outer layer of the sun’s atmosphere, while the Extreme ultraviolet Variability Experiment, or EVE, measures its ultraviolet spectrum every 10 seconds, 24 hours a day.

We are now less than 12 hours from launch of SDO, NASA’s “New Eye on the Sun”.

Read my earlier SDO reports, including from on site at the KSC launch pads for both SDO and STS 130.

NASA’s Solar Crown Jewel Bolted atop Atlas Rocket

NASA advanced Solar Observatory nearing February launch; will send IMAX like movies daily

Learn more at the NASA SDO Website

See a cool new video explaining SDO here:
The Solar Dynamics Observatory in 3.5 Minutes

Atlas rocket has been rolled to pad 41 on Feb 8, 2010 and is locked in place surrounded by four lightening masts. Credit: Ken Kremer
Atlas V rocket begins the 1800 ft rollout from VIF to Pad 41. Credit: Ken Kremer
Posted on by Ken Kremer

NASAs Solar Crown Jewel Bolted atop Atlas Rocket

NASA's Solar Dynamics Observatory is lifted atop the Atlas V rocket. Credit: NASA/Jack Pfaller

[/caption]The “Crown Jewel” of NASA’s solar science research fleet, the Solar Dynamics Observatory, or SDO, was transported from the Astrotech payload processing facility outside KSC to the Vertical Integration Facility (VIF) at Launch Complex 41 in the overnight hours of Jan 26. It’s standard operating procedure to transport such highly valuable payloads after midnight, when the least amount of traffic is on the road in order to minimize any possibility for an accident. This journey was in preparation for connecting to its Atlas rocket. The $848 million spacecraft was moved at about 10 MPH on a specially designed flat bed truck for a trip lasting roughly four hours.

SDO is bolted onto Centaur Upper Stage. Credit: NASA/Jack Pfaller
After daylight broke, the encapsulated SDO was lifted by crane, hoisted 13 stories to the top of the Atlas V rocket and bolted atop the Centaur upper stage previously erected inside the gantry at Cape Canaveral Air Force Station. Interface and aliveness tests of the integrated system to verify electrical connections between SDO and the booster rocket are underway.

The Flight Readiness Review is set for Feb. 5 and pad rollout on Feb. 8. NASA is currently targeting Feb 9 as the launch date with a 1 hour launch window starting at 10:30 AM EST, just 2 days after the scheduled Feb. 7 blast off of Shuttle Endeavour and Tranquility module on the STS 130 mission to the ISS. If STS 130 is delayed, SDO would likewise be delayed on a matching day by day basis. A minimum turnaround time of 48 hours is required to reconfigure all telemetry and tracking systems and hardware on the Air Force Eastern range between launches.

I’ll be reporting from the launch pads for both SDO and STS 130.
Read my earlier preview article on SDO:
NASA advanced Solar Observatory nearing February launch; will send IMAX like movies daily

See a cool new video explaining SDO here:
The Solar Dynamics Observatory in 3.5 Minutes

Learn more at the NASA SDO Website

In the Vertical Integration Facility at Launch Complex 41 on Cape Canaveral Air Force Station, the payload fairing enclosing NASA's Solar Dynamics Observatory, or SDO, has been secured to the Atlas V rocket. SDO is the first mission in NASA's Living With a Star Program. Credit: NASA/Jack Pfaller
Posted on by Nancy Atkinson

The Solar Dynamics Observatory in 3.5 Minutes

This great new video (just uploaded today!) does a great job of explaining the upcoming Solar Dynamics Observatory (SDO) mission, which is slated to launch on Feb. 9, 2010. SDO will provide a new eye on the sun that will deliver solar images with 10 times better resolution than high-definition television. This mission will zoom in on the cause of severe space weather—solar activity such as sunspots, solar flares, and coronal mass ejections. It will give us the best look ever at our Sun.

For more information see our detailed preview article on SDO.

Posted on by Ken Kremer

NASA advanced Solar Observatory nearing February launch; will send IMAX like movies daily

SDO and two piece payload fairing inside “clean room” at Astrotech Spaceflight facility near KSC on Jan 21. Fairing protects spacecraft during ascent through earths atmosphere. Credit: Ben Cooper/Spaceflight Now

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NASA’s new solar science satellite, dubbed the Solar Dynamics Observatory, or SDO, moved an important step closer to launch when it was encapsulated inside its two piece payload fairing on Thursday (Jan 21) at the Astrotech Space Operations Facility nearby to the Kennedy Space Center (KSC). SDO is the most sophisticated spacecraft ever designed and constructed to study the sun and its dynamic behavior.

Liftoff of SDO aboard an Atlas V rocket from Cape Canaveral Air Force Station is targeted for Feb 9, just 2 days after the shuttle Endeavour blasts off with the Tranquility module and heads for the ISS.

“SDO will revolutionize our view of the sun. It will reveal how solar activity affects our planet and help us anticipate what lies ahead”, said Madhulika Guhathakurta at a Jan 21 press briefing. She is the SDO program scientist at NASA Headquarters.

The enclosed observatory will be transported on a specially designed trailer to Launch Complex 41 on Tuesday (Jan. 26) and then be hoisted up and bolted atop the two stage booster rocket. The 19 story tall Atlas V will propel the 8,800 pound spacecraft into an inclined geosynchronous orbit where it will study the sun in multiple wavelengths during its 5 year primary mission. It carries sufficient fuel to operate for another 5 years.

An Atlas rocket similar to this vehicle I observed at Cape Canaveral Pad 41 will launch SDO. Credit: Ken Kremer
SDO arrived at KSC on July 9 for final processing, testing and fueling operations. It was shipped from NASA’s Goddard Space flight Center where it was built by teams of technicians, engineers and scientists at a cost of $848 million.

SDO is the first spacecraft to be launched as part of NASA’s Living with a Star (LWS) science program initiative. The goal is to better understand the causes of solar variability and to create better forecasts for predicting “space weather” which directly affects the Earth and all life inhabiting it. Furthermore, this information will be used to help protect and provide early warning to valuable satellites operating in space as well as astronaut crews working aboard the International Space Station.

When active regions on the sun erupt suddenly and violently in the form of a solar flare or coronal mass ejection (CME), they hurl millions of tons of solar material and charged particles toward Earth which can damage orbiting satellites, disrupt navigation systems and cause failures in the power grid.

SDO is equipped with 3 science instruments which will measure and characterize in-depth the Suns interior and atmosphere, magnetic field, hot plasma of the solar corona and the density of the radiation that creates the ionosphere of the planets.

SDO will collect huge volumes of data which amount to a staggering 1.5 terabytes per day. This is the equivalent of downloading a half million songs each day or filling a CD every 36 seconds. “That’s almost 50 times more science data than any other mission in NASA history”, says Dean Pesnell, the SDO project scientist at NASA Goddard.

SDO is enclosed in its payload fairing and ready for transport on Jan 26 to Atlas V launch pad. Credit: NASA/Jim Grossman
“SDO is going to send us images ten times better than high definition television” according to Pesnell. “The pixel count is comparable to an IMAX movie — an IMAX filled with the raging sun, 24 hours a day.”

“We’ll be getting IMAX-quality images every 10 seconds,” says Pesnell. “We’ll see every nuance of solar activity.” Because no orbiting spacecraft has ever come even close to this incredible speed, there is a vast potential for ground breaking science discoveries. Scientists hope to learn how storms are generated inside the sun and how they then evolve and propagate outwards through the suns atmosphere and towards earth and the rest of the solar system.

Since SDO has no on-board recording system, the data will be transmitted continuously on a 24/7 basis to dedicated receiving stations on the ground in New Mexico as it maintains position over 22,000 miles high above earths equator.

I will be reporting on site from the Kennedy Space Center in February and directly from the launch pads for both SDO and STS 130. See my earlier STS 130 reports here.

NASA SDO Website

Posted on by Nancy Atkinson

Cluster Satellite Detects Rifts in Earth’s Magnetic Field

Illustration of solar wind impact on Earth's magnetosphere Copyright: NASA

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While Earth’s magnetic field protects our planet from most of the permanent flow of particles from the solar wind, rifts or fissures in natural shield are known to occur, enabling the solar wind to penetrate our near-space environment. An ESA satellite cluster called, appropriately, Cluster has provided new insight into the location and duration of these ruptures in the Earth’s magnetic shield, and reveals while our atmosphere protects us for the most part, clear effects of these rifts have been detected high in the upper atmosphere and in the region of space around Earth where satellites orbit.

This study reports the observation of fissures on the Sun-facing side of the Earth’s magnetic shield – the dayside magnetopause. Fortunately, these fissures don’t expose Earth’s surface to the solar wind; our atmosphere protects us. But the upper atmosphere is affected. ,

clear effects have been detected high in the upper atmosphere and in the region of space around Earth where satellites orbit. Credit: ESA

The dominant physical process causing these cracks is known as magnetic reconnection, a process whereby magnetic field lines from different magnetic domains collide and reconnect: opening the closed magnetic shield. Magnetic reconnection is a physical process at work throughout the Universe, from star formation to solar explosions to experimental fusion reactors on Earth. However, the conditions under which it occurs and how long it lasts remain unclear.

What is known is that magnetic reconnection leads to the mixing of previously separated plasmas when, for instance, the solar wind plasma enters the magnetosphere. In this instance the two magnetic domains are the Earth’s internal magnetic field, and the interplanetary magnetic field (IMF). (The solar wind is not only composed of solar particles (mostly protons and electrons), it also carries the Sun’s magnetic field. Out among the planets, this field is the IMF.)

For more than 700,000 years, the South to North orientation of the terrestrial magnetic field has been rather steady. In contrast, the IMF orientation is highly variable, with total inversion frequently observed on times-scales of minutes.

Reconnection between the IMF and the Earth’s magnetic field critically depends on the angle between these fields. Space physicists have made a distinction between reconnection when both fields are in opposite directions, or anti-parallel, and component reconnection, when the IMF is neither parallel nor anti-parallel to the terrestrial magnetic field. The distinction is important since component and anti-parallel reconnection have different onset characteristics and lead to different duration of the fissures in the magnetic shield. The distinction between these two types of magnetic reconnection has been the subject of hot debate among space scientists for many years.

The position, on 25 February 2005, of the Cluster satellite constellation and the Double Star TC-1 satellite with respect to the magnetopause. Blue lines represent magnetic field lines related to the Earth's magnetic field. Spacecraft configurations are scaled by a factor of 5.

For the first time, four spacecraft flying in constellation (the ESA Cluster mission), have provided unambiguous evidence of anti-parallel reconnection at high latitude on the dayside magnetopause, occurring quasi-simultaneously with a period of low-latitude component reconnection detected by the Sino-European Double Star TC-1 satellite. TC-1 and the Cluster array (with the Cluster spacecraft separated by ~2000 km) are more than 30,000 km apart (see below.) The 3D reconnection picture, determined by repeated sampling of the ion diffusion region and associated magnetic null fields (i.e. the heart of the reconnection process). 2.

“These observations support the idea that both anti-parallel and component reconnection occur at the dayside magnetopause under the same IMF conditions and that both phenomena might be the local signatures of a global reconnection picture”, says Professor Malcolm Dunlop from the Rutherford Appleton Laboratory, Didcot, UK.

“This remarkable set of observations shows that magnetic reconnection at the magnetopause is not as simple as it is described in textbooks! It also demonstrates the need for the capability to study magnetic reconnection at multiple scales simultaneously”, says Matt Taylor, acting Cluster project scientist at the European Space Agency.

Source: ESA

Posted on by Nancy Atkinson

Solar Flares Can Now Be Predicted More Accurately

An eruption on the Sun. Credit: NASA

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We all like to know in advance what the weather is going to be like, and space weather is no different. However, predicting solar storms from the sun — which can disrupt satellites and even ground-based technologies — has been difficult. But now scientists say magnetic loops breaking inside the sun provide two to three-day warnings of solar flares. “For the first time, we can tell two to three days in advance when and where a solar flare will occur and how large it will be,” said Alysha Reinard, from the NOAA Space Weather Prediction Center.

Reinard and her team found that sound waves recorded from more than 1,000 sunspot regions reveal disruptions in the sun’s interior magnetic loops that predict a solar flare. They found the same pattern in region after region: magnetic twisting that tightened to the breaking point, burst into a large flare, and vanished. They established that the pattern could be used as a reliable tool for predicting a solar flare.

“These recurring motions of the magnetic field, playing out unseen beneath the solar surface, are the clue we’ve needed to know that a large flare is coming—and when,” said Reinard.

Twisting magnetic fields beneath the surface of the sun erupt into a large solar flare, as shown above. Credit: NOAA

The new technique is already twice as accurate as current methods, according to the authors, and that number is expected to improve as they refine their work over the next few years. With this technique, reliable watches and warnings should be possible before the next solar sunspot maximum, predicted to occur in 2013.
“Two or three days lead time can make the difference between safeguarding the advanced technologies we depend on every day for our livelihood and security, and the catastrophic loss of these capabilities and trillions of dollars in disrupted commerce,” said Thomas Bogdan, director of NOAA’s Space Weather Prediction Center.

The team’s paper has been accepted for publication by the Astrophysical Journal Letters.

Source: NOAA

Posted on by Nancy Atkinson

Eclipse Sunspots Signal Increased Activity

Sun sunspots show up during the recent annular eclipse. Credit: Shehal Joseph and Romayne Anthony

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Astrophotographers capturing the recent annular solar eclipse on January 15, 2010 got an added bonus: upon closer inspection, they found sunspot 1040 also showed up on their images, too. “We didn’t mean to catch sunspots in our Jaffna Eclipse expedition, nor did we plan to,” said Prasanna Deshapriya, one of the members of the Eclipse Hunt 2010 crew, featured in our eclipse photo and video collection. “But surprisingly this is what really happened.”

SOHO image of sunspot 1040 on January 15, 2010. credit: SOHO/MDI

The rather big sunspot 1040, which was also captured by the SOHO spacecraft on Jan. 15 has just disappeared over the sun’s western limb, currently leaving the visible disk of the sun blank once again in this uncharacteristically long solar minimum. But our old friend, sunspot 1039 should be showing up soon, as the sun rotates around. We know it is still there, because the STEREO spacecraft can show us what is going on the sun’s far side. Sunspot 1039 should emerge for direct viewing from Earth within the next 48 hours. Spaceweather.com encourages those amateur astronomers with solar telescopes to monitor the Sun’s east limb for developments.

STEREO B captures the largest solar flare in two years. Click for larger movie.

Additionally on Jan. 19th at 1340 UT, STEREO-B recorded the strongest solar flare in almost two years. Click the image to see the action on an ultraviolet movie of the blast. The M2-class eruption came from sunspot 1039, so that sunspot is likely still very active.

Spaceweather.com said that considering the sunspot was not even visible from Earth at the time of the eruption, the flare was probably much stronger than its M2 classification would suggest. This active region has produced at least three significant eruptions since Jan. 17th and it shows no signs of cooling off.

Sources: Eclipse 2010 blog, Spaceweather.com from 01/19/2010 , Kanabona.com

Posted on by Nancy Atkinson

Unprecedented Images Show Betelgeuse Has Sunspots

Caption:The surface of Betelgeuse in near infrared at 1.64 micron in wavelength, obtained with the IOTA interferometer (Arizona). The image has been re-constructed with two different algorithms, which yield the same details, of 9 milliarcseconds (mas). The star diameter is about 45 milliarcseconds. Credit: Copyright 2010 Haubois / Perrin (LESIA, Observatoire de Paris)

An international team of astronomers has obtained an unprecedented image of the surface of the red supergiant Betelgeuse, in the constellation Orion. The image reveals the presence of two giant bright spots, which cover a large fraction of the surface. Their size is equivalent to the Earth-Sun distance. This observation provides the first strong and direct indication of the presence of the convection phenomenon, transport of heat by moving matter, in a star other than the Sun. This result provides a better understanding of the structure and evolution of supergiants.

Betelgeuse is a red supergiant located in the constellation of Orion, and is quite different from our Sun. First, it is a huge star. If it were the center of our Solar System it would extend to the orbit of Jupiter. At 600 times larger than our Sun, it radiates approximately 100,000 times more energy. Additionally, with an age of only a few million years, the Betelgeuse star is already nearing the end of its life and is soon doomed to explode as a supernova. When it does, the supernova should be seen easily from Earth, even in broad daylight.

But we now know Betelgeuse has some similarities to the Sun, as it also has sunspots. The surface has bright and dark spots, which are actually regions that are hot and cold spots on the star. The spots appear due to convection, i.e., the transport of heat by matter currents. This phenomenon is observed every day in boiling water. On the surface of the Sun, these spots are rather well-known and visible. However, it is not at all the case for other stars and in particular supergiants. The size, physical characteristics, and lifetime of these dynamical structures remain unknown.

Betelgeuse is a good target for interferometry because its size and brightness make it easier to observe. Using simultaneously the three telescopes of the Infrared Optical Telescope Array (IOTA) interferometer on Mount Hopkins in Arizona (since removed), and the Paris Observatory (LESIA) the astronomers were able to obtain a numerous high-precision measurements. These made it possible to reconstruct an image of the star surface thanks to two algorithms and computer programs.

Two different algorithms gave the same image. One was created by Eric Thiebaut from the Astronomical Research Center of Lyon (CRAL) and the other was developed by Laurent Mugnier and Serge Meimon from ONERA. The final image reveals the star surface with unprecedented, never-before-seen details. Two bright spots clearly show up next to the center of the star.

The analysis of the brightness of the spots shows a variation of 500 degrees compared to the average temperature of the star (3,600 Kelvin). The largest of the two structures has a dimension equivalent
to the quarter of the star diameter (or one and a half the Earth-Sun distance). This marks a clear difference with the Sun where the convection cells are much finer and reach hardly 1/20th of the solar radius (a few Earth radii). These characteristics are compatible with the idea of luminous spots produced by convection. These results constitute a first strong and direct indication of the presence of convection on the surface of a star other than the Sun.

Convection could play an important role in the explanation of the mass-loss phenomenon and in the gigantic plume of gas that is expelled from Betelgeuse. The latter has been discovered by a team led by Pierre Kervella from Paris Observatory (read our article about this discovery). Convection cells are potentially at the origin of the hot gas ejections.

The astronomers say this new discovery provides new insights into supergiant stars, opening up a new field of research.

Sources: Abstract: arXiv, Paper: “Imaging the spotty surface of Betelgeuse in the H band,” 2009, A&A, 508, 923″. Paris Observatory