The All Sky Automated Survey for SuperNovae (ASAS-SN) is an automated program to search for new

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

e and other astronomical transients, headed by astronomers from the

Ohio State University The Ohio State University, commonly called Ohio State or OSU, is a public land-grant research university in Columbus, Ohio. A member of the University System of Ohio, it has been ranked by major institutional rankings among the best publ ...

, including

Christopher Kochanek Christopher Kochanek is an American astronomer. He works in the fields of cosmology, gravitational lensing, and supernovae. Kochanek currently is an Ohio Eminent Scholar at Ohio State University as well as an Elected Fellow of the American Associat ...

and

Krzysztof Stanek Krzysztof Stanek is an observational astrophysicist and Professor and University Distinguished Scholar at Ohio State University. He was named a University Distinguished Scholar in 2018. His research focus is on the explosive deaths of massive s ...

. It has 20 robotic telescopes in both the northern and southern hemispheres. It can survey the entire sky approximately once every day. Initially, there were four ASAS-SN telescopes at Haleakala and another four at Cerro Tololo, a

Las Cumbres Observatory Las Cumbres Observatory (LCO) is a network of astronomical observatories run by a non-profit private operating foundation directed by the technologist Wayne Rosing. Its offices are in Goleta, California. The telescopes are located at both north ...

site. Twelve more telescopes were deployed in 2017 in Chile, South Africa and Texas, with funds from the

Gordon and Betty Moore Foundation The Gordon and Betty Moore Foundation is an American foundation established by Intel co-founder Gordon E. Moore and his wife Betty I. Moore in September 2000 to support scientific discovery, environmental conservation, patient care improvements a ...

, the Ohio State University, the Mount Cuba Astronomical Foundation, China, Chile, Denmark, and Germany. All the telescopes (Nikon telephoto 400mm/F2.8 lenses) have a diameter of 14 cm and ProLine PL230 CCD cameras. The pixel resolution in the cameras is 7.8 arc seconds, so follow-up observations on other telescopes are usually required to get a more accurate location. The main goal of the project is to look for bright supernovae, and its discoveries have included the most powerful supernova event ever discovered,

ASASSN-15lh ASASSN-15lh ( supernova designation SN 2015L) is an extremely luminous astronomical transient event discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN), with the appearance of a superluminous supernova event. It was first dete ...

. However, other transient objects are frequently discovered, including nearby

tidal disruption event A tidal disruption event (TDE) is an astronomical phenomenon that occurs when a star approaches sufficiently close to a supermassive black hole (SMBH) to be pulled apart by the black hole's tidal force, experiencing spaghettification. A portion ...

s (TDEs) (e.g.,

ASASSN-19bt ASASSN-19bt is a tidal disruption event, a star destroyed by a black hole, discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN) project, with early-time, detailed observations by the TESS satellite. It was first detected on Januar ...

), Galactic

nova A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...

e (e.g.,

ASASSN-16kt V407 Lupi, also known as Nova Lupi 2016, was a bright nova in the constellation Lupus discovered by All Sky Automated Survey for SuperNovae (ASAS-SN) on 24.00 September 2016. At the time of its discovery, it had an apparent visual magn ...

ASASSN-16ma V5856 Sagittarii, also known as Nova Sagittarii 2016 Number 4, was the 4th and brightest nova that occurred in the constellation Sagittarius during 2016. It was discovered by the All Sky Automated Survey for SuperNovae (which assigned ...

, and

ASASSN-18fv V906 Carinae, also known as Nova Carinae 2018, was a nova in the Milky Way galaxy which appeared in the constellation Carina, near the 5th magnitude star HD 92063. It was discovered on images taken on 20.32 March 2018 by the All Sky A ...

cataclysmic variable In astronomy, cataclysmic variable stars (CVs) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state. They were initially called novae (), since ones with an outburst brightness visible to ...

s, and

stellar flare The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star. Computer scientists and mathematicians often voc ...

s, including several of the largest flares ever seen. In July 2017 ASAS-SN discovered its first comet,

ASASSN1 C/2017 O1 (ASASSN) is a comet discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN). It was first detected on July 19, 2017, located in the southern constellation Cetus. Discovery During the ongoing ASAS-SN survey, using data from ...

, and in July 2019 it provided crucial data for the near-Earth asteroid 2019 OK. It can detect new objects with magnitudes between 18 and 8. Objects discovered receive designations starting with ''ASASSN'' followed by a dash, a two digit year and letters, for example

. Thomas W.-S. Holoien
an
22 others Astrophysical Journal (September 26, 2019) Discovery and Early Evolution of ASASSN-19bt, the First TDE Detected by TESS
Transiting Exoplanet Survey Satellite

References

External links

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