VVV-WIT-07 is a unique

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

which presents a sequence of recurrent dimmings (K_s~14.35 – 16.164) with a possible deep

eclipse An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ...

in July 2012. The star, located in the

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation whose recognition pred ...

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

about away, is not a

binary star A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...

, which would eliminate such a system from explaining the various observed dimmings.

Overview

The star was found by the "

Vista Variables in the Via Lactea VISTA Variables in the Via Lactea –The VVV Survey– is observing the Milky Way's bulge (astronomy), bulge and southern disk in the near-infrared using the capabilities of the VISTA (telescope), VISTA Telescope at Paranal, Chile. The survey sta ...

" (VVV) project, which is a survey of

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 m ...

(ESO) variability of the innermost bulge of the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

. The

near-infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of ...

spectra of VVV-WIT-07 appear without features, without prominent emission or absorption lines. The characteristics found in the

light curve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

of VVV-WIT-07 (WIT refers to "What Is This?") are similar to those seen in

J1407 V1400 Centauri, also known as 1SWASP J140747.93−394542.6 or simply J1407, is a young, pre-main-sequence star that was eclipsed by the likely free-floating substellar object J1407b in April–June 2007. With an age around 20 million ye ...

( Mamajek's Object), a pre-MS K5 dwarf with a ring system that eclipses the star or, alternatively, to

Tabby's star Tabby's Star (designated as KIC 8462852 in the Kepler Input Catalog and also known by the names Boyajian's Star and WTF (Where'sTheFlux?) Star, is a binary star in the constellation Cygnus approximately from Earth. The system is compo ...

, an F3 IV/V star that shows irregular and aperiodic obscurations in its light curve. From 2010 to 2018, the star dimmed and brightened irregularly (v~14.35 – 16.164), and seemed similar to

, except the light from VVV-WIT-07 dimmed by up to 80 percent, while Tabby's star faded by only about 20 percent. Another star,

, however, has been found to have dimmed by up to 95%, which may be more similar to the light curve presented by VVV-WIT-07. Nonetheless, according to ESO astronomer Valentin Ivanov, "A key word that could be used to describe our finding f VVV-WIT-07is extreme. In every aspect ... We have identified a system that challenges the imagination even more than usual, because it is so unlike our own planetary system."

References

External links

* , a presentation by Tabetha S. Boyajian (2016). * , a presentation by Issac Arthur (2016). * , star with unusual light fluctuations (2017). * , up to 80% dimming. {{Portal bar, Astronomy, Stars, Outer space Astronomical objects discovered in 2018 Scorpius 2018 in science Unsolved problems in astronomy

Overview

See also

References

External links