RZ Piscium (or RZ Psc) is a UX Orionis type

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 ...

away, in the

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 ...

Pisces Pisces may refer to: *Pisces (astrology), an astrological sign Astronomy *Pisces (constellation), a constellation ** Pisces Overdensity, an overdensity of stars in the Milky Way's halo that is situated in the Pisces constellation ** Pisces II, a ...

. Over the years, the star has been found to brighten and dim erratically, dimming by as much as a tenth of its usual luminosity. RZ Piscium has been found to emit large amounts of

infrared radiation 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 ...

, suggesting the presence of a substantial mass of gas and dust orbiting the star, possibly from a "

disrupted planet In astronomy, a disrupted planet is a planet or exoplanet or, perhaps on a somewhat smaller scale, a planetary-mass object, planetesimal, moon, exomoon or asteroid that has been disrupted or destroyed by a nearby or passing astronomical body or ...

Disrupted planet

Because of the

infrared excess An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator. Infrared excesses are of ...

and rapid light variations, astronomers conclude that: According to astronomer Ben Zuckerman:

Observations

In 2017, RZ Piscium was studied using the XMM-Newton satellite, the Shane 3-meter telescope at

Lick Observatory The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and the 10-meter Keck I telescope at

W. M. Keck Observatory The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and, when c ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. The temperature of the star was found to be about the same as the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

(). Further, the star was found to produce about a thousand times more

x-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

s than the Sun, suggesting that the star is relatively young. On the other hand, RZ Piscium was found to contain a relatively small amount of surface

lithium Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...

, which suggests the star is between 30 − 50 million years old; this is somewhat "old" for a star with so much circumstellar dust. Most young stars that are as dusty as RZ Piscium may be producing planets, but given its relatively advanced age, RZ Piscium may be destroying and consuming its planets instead. In 2020, a red dwarf companion with the mass of 0.12

Solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

was detected with a projected separation of 23 AU from the primary star. The incandescence of the companion star thus make up about one third of excess infrared emission previously attributed to the dust.

References

External links

* , star with unusual light fluctuations (21 December 2017). * , a presentation by Tabetha S. Boyajian * , a presentation by Issac Arthur {{Sky, 01, 09, 42.0523, +, 27, 57, 01.9121, 550 Pisces (constellation) Planetary rings 2017 in science Piscium, RZ J01094205+2757020 K-type subgiants Herbig Ae/Be stars

Disrupted planet

Observations

See also

References

External links