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 site. Twelve more telescopes were deployed in 2017 in Chile, South Africa and Texas, with funds from the Gordon and Betty Moore Foundation, 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 detect ...

. However, other transient objects are frequently discovered, including nearby tidal disruption events (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, ASASSN-16ma, and ASASSN-18fv),

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 flares, including several of the largest flares ever seen. In July 2017 ASAS-SN discovered its first comet, ASASSN1, and in July 2019 it provided crucial data for the near-Earth asteroid

2019 OK 2019 OK is a near-Earth asteroid noted for its sudden, surprise discovery on the day before its close flyby in 2019. The object's size is estimated at across, the closest asteroid of such size discovered in 2019. It is uncommon for asteroids of ...

. 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

* * — Yes, that

Nemesis In ancient Greek religion, Nemesis, also called Rhamnousia or Rhamnusia ( grc, Ῥαμνουσία, Rhamnousía, the goddess of Rhamnous), was the goddess who personifies retribution, a central concept in the Greek world view. Etymology The n ...

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