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Mission type | Astronomy · Planetary science |
---|---|
Operator | Observatoire de Paris · CNRS |
COSPAR ID | 2018-004W |
SATCAT no. | 43132 ![]() |
Website | http://picsat.obspm.fr |
Mission duration | ~1 year |
Spacecraft properties | |
Bus | CubeSat 3U |
Manufacturer | ISIS (spacecraft) Hyperion (ADCS) LESIA (payload) |
Launch mass | 3.9 kg |
Dimensions | 10 × 50 × 100 cm with antennas and solar panels |
Power | 6 watts |
Start of mission | |
Launch date | 12 January 2018, 03:58 UTC |
Rocket | PSLV |
Launch site | SDSC |
Contractor | ISL · ANTRIX |
End of mission | |
Last contact | 20 March 2018 |
Decay date | 3 October 2023 |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth · SSO |
Inclination | 97.3° |
Period | 95 minutes |
Main telescope | |
Type | Off-axis telescope |
Diameter | 50 mm |
Focal length | 150 mm |
Focal ratio | f/4 |
Wavelengths | visible light |
Transponders | |
Band | VHF · UHF |
PicSat was a French observatory nanosatellite, designed to measure the transit of Beta Pictoris b, an exoplanet which orbits the star Beta Pictoris.
PicSat was designed and built by a team of scientists led by Dr. Sylvestre Lacour, astrophysicist and instrumentalist at the High Angular Resolution in Astrophysics group in the LESIA laboratory with Paris Observatory, Paris Sciences et Lettres University and the French National Centre for Scientific Research (CNRS). It was launched on 12 January 2018, and operated for more than 10 weeks before falling silent on 20 March 2018. [1] The cubesat decayed from orbit on 3 October 2023. [2]
![]() | This section possibly contains original research .(December 2018) |
With an age of about 23 million years, Beta Pictoris is a very young star. Compared to the Sun, which is 4.5 billion years old, Beta Pictoris is about twice as large in mass and size. Beta Pictoris is relatively close to the Sun: just 63.4 light-years away, making it bright and easy to observe. This makes Beta Pictoris interesting for study as it allows astronomers to learn more about the very early stages of planet formation.
In the early 1980s, a large disk of asteroids, dust, gas, and other debris were found surrounding Beta Pictoris, leftovers from the formation of the star. [3] In 2009, a giant gas planet orbiting Beta Pictoris was discovered by a team of French astronomers led by Anne-Marie Lagrange from Grenoble, France. [4] The planet, named Beta Pictoris b, is about seven times as massive as Jupiter. It orbits Beta Pictoris from a distance at around ten astronomical units: ten times the distance between the Earth and the Sun, and about the same distance between Saturn and the Sun.
In 2016, it was predicted that Beta Pictoris b's Hill sphere or the planet itself would be passing in front of its star as seen from the Earth. [5] The detailed observation of such a transit would reveal detailed information about the planet, such as its exact size, the composition of its atmosphere, its density, and its chemical composition. Because Beta Pictoris b is so young, this information would reveal more about the formation of giant planets and planetary systems.
However, as Beta Pictoris b's orbit is not well known, the moment of transit could only be estimated roughly. The transit was predicted to occur between the summer of 2017 and the summer of 2018. A transit of the planet would have lasted only a few hours; a transit of the planet's Hill sphere would have lasted anywhere from days to months. Continuous monitoring would have been the only way to capture the phenomenon. Since Earth-based observatories would not be able to accurately capture the transit, as long-term continuous monitoring was unlikely to work with Earth's atmosphere, day-night cycle changes, and scheduling conflicts, only a satellite could accurately capture the transit.
The purpose of PicSat was to continually observe Beta Pictoris' brightness in order to capture the change in brightness when Beta Pictoris b transited over the star and partially blocked some light.
PicSat, a contraction of "Beta Pictoris" and "satellite", was a CubeSat. PicSat was composed of three standard cubic units, called a "3U", each 10x10x10cm in size. [6]
PicSat was the first CubeSat to be operated by the CNRS. It was different from most CubeSat projects in that it was developed by professionals, not by students. The project began in 2014 when Sylvestre Lacour, astrophysicist and instrumentalist at the French CNRS at the LESIA laboratory / Paris Observatory, thought of using a CubeSat to observe Beta Pictoris b's transit. He gathered a small team and they designed and built PicSat.
PicSat was one of the few CubeSats worldwide with an astrophysical science goal and the first CubeSat in the field of exoplanetary science. The PicSat science case was defined in collaboration with Dr. Alain Lecavelier des Etangs from the Institut d’Astrophysique de Paris, who had been working on the Beta Pictoris system for many years. The PicSat project also involved a collaboration with CCERES, the "Center & Campus" space of PSL Research University, and with French Space Agency CNES experts. [7]
PicSat consisted of three cubic units. The top and middle cubic units held the satellite's payload, and the bottom unit contained its onboard computer.
PicSat's topmost unit contained a small telescope with a five-centimeter diameter mirror. The mirror's small size was sufficient, as Beta Pictoris is very bright.
The middle unit contained two innovative technical tools: its fine-tracking ability, and its usage of a thin optical fiber, 3 micrometers in diameter. The fiber, whose usage marks the first time an optical fiber was flown into space, receives light photons and guides them to a sensitive photodiode that accurately measures the arrival time of each individual photon. Using an thin optical fiber eliminated other light sources, like stray light from the sky and scattered light from within the optical system, from entering the photodiode, allowing for accurate measurement of Beta Pictoris' brightness. A fast-moving piezoelectric actuator was added to PicSat to keep the optical fiber tracked upon Beta Pictoris, since the natural wobble of the satellite's orbit would affect the fiber's ability to accurately track and measure the star.
The bottom cubic unit of PicSat contained the onboard computer for the satellite's operation, ground-station communication with Earth, raw pointing of the telescope, battery operation, and other important monitoring tasks. [8]
The whole satellite was clothed in arrays of deployable solar panels, providing energy for all systems. PicSat's total weight was about 3.5 kilograms, and its power consumption was about 5 watts. [9]
If PicSat ever detected the onset of Beta Pictoris b's transit, or the transit of its Hill sphere, then a European Southern Observatory telescope would have been immediately put into action. [10] This was thanks to an accepted proposal to ESO for an opportunity to observe time in support of the PicSat project, led by Dr. Flavien Kiefer from the Institut d'astrophysique de Paris. Dr. Kiefer was known for his work on the detection and observation of exocomets in star systems such as Beta Pictoris. [11]
The telescope was equipped with the High Accuracy Radial Velocity Planet Searcher (HARPS) instrument. [10] Together with PicSat measurements, HARPS transit data would have allowed for more accurate determinations of the orbit and size of the planet, along with the chemical make up of its atmosphere. If a comet were to have transited, HARPS would have been able to determine the chemical composition of the comet's atmosphere, which carries key information about the chemical composition of the star system as a whole and thus its formation and evolution. [12]
PicSat was launched into a polar, low Earth orbit with an altitude of 600 km on 12 January 2018. The launch was carried out by the Indian Space Research Organization using a Polar Satellite Launch Vehicle on the PSLV-C40 mission. [13]
The satellite was operated from the PicSat Ground Station at Paris Observatory, although it only was visible for about 30 minutes a day. Since PicSat communicated with amateur radio frequencies (achieved with cooperation with Réseau des Émetteurs Français), anyone with radio receiving capabilities was able to tune into, receive, and upload information from PicSat to a database. A large network of radio amateurs were called to collaborate to track the satellite, receive its data, and transmit it to Ground Station. Licensed radio amateurs were able to use PicSat as a transponder when it was not performing observation tasks or other communication. [14] PicSat's official website displayed received information, as well as up-to-date light curve data of Beta Pictoris.
PicSat was predicted to operate for one year. [15] It operated for approximately 10 weeks before contact was lost on 20 March 2018. [1] Attempts to reestablish contact were made. On 30 March it was believed contact was restored by a team at Morehead State University, but the signal received was from the TIGRISAT satellite. The mission officially concluded on 5 April.
PicSat was financially supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program Lithium proposal 639248, the CNRS, the ESEP Laboratory Group, the PSL Research University, Foundation MERAC, CNES, CCERES, and the Paris Observatory – LESIA. [16]
The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with a primary mirror that measures 8.2 meters in diameter. These optical telescopes, named Antu, Kueyen, Melipal, and Yepun, are generally used separately but can be combined to achieve a very high angular resolution. The VLT array is also complemented by four movable Auxiliary Telescopes (ATs) with 1.8-meter apertures.
The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based astronomy. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and access to the southern sky. The organisation employs over 750 staff members and receives annual member state contributions of approximately €162 million. Its observatories are located in northern Chile.
CoRoT was a space telescope mission which operated from 2006 to 2013. The mission's two objectives were to search for extrasolar planets with short orbital periods, particularly those of large terrestrial size, and to perform asteroseismology by measuring solar-like oscillations in stars. The mission was led by the French Space Agency (CNES) in conjunction with the European Space Agency (ESA) and other international partners.
Pictor is a constellation in the Southern Celestial Hemisphere, located between the star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, and is an abbreviation of the older name Equuleus Pictoris. Normally represented as an easel, Pictor was named by Abbé Nicolas-Louis de Lacaille in the 18th century. The constellation's brightest star is Alpha Pictoris, a white main-sequence star around 97 light-years away from Earth. Pictor also hosts RR Pictoris, a cataclysmic variable star system that flared up as a nova, reaching apparent (visual) magnitude 1.2 in 1925 before fading into obscurity.
A planetary system is a set of gravitationally bound non-stellar objects in or out of orbit around a star or star system. Generally speaking, systems with one or more planets constitute a planetary system, although such systems may also consist of bodies such as dwarf planets, asteroids, natural satellites, meteoroids, comets, planetesimals and circumstellar disks. The Sun together with the planetary system revolving around it, including Earth, forms the Solar System. The term exoplanetary system is sometimes used in reference to other planetary systems.
Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light-years (19.4 pc) from the Solar System, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 20 to 26 million years old, although it is already in the main sequence stage of its evolution. Beta Pictoris is the title member of the Beta Pictoris moving group, an association of young stars which share the same motion through space and have the same age.
The High Accuracy Radial Velocity Planet Searcher (HARPS) is a high-precision echelle planet-finding spectrograph installed in 2002 on the ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003. HARPS has discovered over 130 exoplanets to date, with the first one in 2004, making it the most successful planet finder behind the Kepler space observatory. It is a second-generation radial-velocity spectrograph, based on experience with the ELODIE and CORALIE instruments.
Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of January 2024 have been observed directly, with even fewer being resolved from their host star.
WASP-6b, also named Boinayel, is an exoplanet approximately 650 light years away in the constellation Aquarius. It was discovered in 2008, by the WASP survey, by astronomical transit across its parent star WASP-6. This planet orbits at only 4% of the Earth-Sun distance. The planet has a mass half that of Jupiter, but its insolation has forced a thermal expansion of its radius to greater than that of Jupiter. Thus, this planet is an inflated hot Jupiter. Starspots on the host star WASP-6 helped to refine the measurements of the mass and the radius of the planet.
Beta Pictoris b (abbreviated as β Pic b) is an exoplanet orbiting the young debris disk A-type main sequence star Beta Pictoris located approximately 63 light-years (19.4 parsecs, or 6×1014 km) away from Earth in the constellation of Pictor. It has a mass around 13 Jupiter masses and a radius around 46% larger than Jupiter's. It orbits at 9 AU from Beta Pictoris, which is about 3.5 times farther than the orbit of Beta Pictoris c. It orbits close to the plane of the debris disk orbiting the star, with a low eccentricity and a period of 20–21 years.
Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic 1.2-metre (47 in) reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of 2,375 m (7,792 ft) at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler.
CoRoT-9b is an exoplanet orbiting the star CoRoT-9, approximately 1500 light years away in the constellation Serpens. CoRoT-9b's distance of nearest approach to its parent star of approximately 0.36 AU was the largest of all known transiting planets at the time of its discovery, with an orbital period of 95 days. The transit of this planet lasts 8 hours. The planet is at a distance from its star where there is a strong increase in albedo as the temperature decreases, because of the condensation of reflective water clouds in the atmosphere. This suggests its atmosphere may be locked into one of two states: a cloudless state with temperatures between 380 K and 430 K, or covered in water clouds with a temperature in the range 250 K to 290 K.
The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) is the corporate name for a pair of Belgian optic robotic telescopes. TRAPPIST–South, which is situated high in the Chilean mountains at ESO's La Silla Observatory, came online in 2010, and TRAPPIST–North situated at the Oukaïmeden Observatory in the Atlas Mountains in Morocco, came online in 2016.
CHEOPS is a European space telescope. Its objective is to determine the size of known extrasolar planets, which will allow the estimation of their mass, density, composition and their formation. Launched on 18 December 2019, it is the first Small-class mission in ESA's Cosmic Vision science programme.
An exocomet, or extrasolar comet, is a comet outside the Solar System, which includes rogue comets and comets that orbit stars other than the Sun. The first exocomets were detected in 1987 around Beta Pictoris, a very young A-type main-sequence star. There are now a total of 27 stars around which exocomets have been observed or suspected.
Spectro-Polarimetric High-contrast Exoplanet REsearch (VLT-SPHERE) is an adaptive optics system and coronagraphic facility at the Very Large Telescope (VLT). It provides direct imaging as well as spectroscopic and polarimetric characterization of exoplanet systems. The instrument operates in the visible and near infrared, achieving exquisite image quality and contrast over a small field of view around bright targets.
ASTERIA was a miniaturized space telescope technology demonstration and opportunistic science mission to conduct astrophysical measurements using a CubeSat. It was designed in collaboration between the Massachusetts Institute of Technology (MIT) and NASA's Jet Propulsion Laboratory. ASTERIA was the first JPL-built CubeSat to have been successfully operated in space. Originally envisioned as a project for training early career scientists and engineers, ASTERIA's technical goal was to achieve arcsecond-level line-of-sight pointing error and highly stable focal plane temperature control. These technologies are important for precision photometry, i.e., the measurement of stellar brightness over time. Precision photometry, in turn, provides a way to study stellar activity, transiting exoplanets, and other astrophysical phenomena.
Anne-Marie Lagrange, born March 12, 1962 in the Rhône-Alpes region of France, is a French astrophysicist. Lagrange's work focuses on the research and study of extrasolar planetary systems. Lagrange is the holder of numerous scientific awards and honorary decorations, including Knight of the Legion of Honour and is a member of the French Academy of Sciences since 2013.
Beta Pictoris c is the second exoplanet discovered orbiting the young star Beta Pictoris, located approximately 63 light-years away from Earth in the constellation of Pictor. Its mass is around nine times that of Jupiter, and it orbits at around 2.7 astronomical units (AU) from Beta Pictoris, about 3.5 times closer to its parent star than Beta Pictoris b. It has an orbital period of 1,200 days. The orbit of Beta Pictoris c is moderately eccentric, with an eccentricity of 0.24.
AF Leporis, also known as HD 35850, is an F-type main-sequence star located 87.5 light-years away from the Solar System in the constellation of Lepus. With an apparent magnitude of 6.3, it is near the limit of naked eye visibility under ideal conditions. While some studies consider it to be a close spectroscopic binary with a separation of 0.021 AU, other studies show no evidence of binarity, and it is likely that the supposed binarity is an artifact resulting from the presence of starspots.