Astronomers have found a new close binary system of helium white dwarfs, the orbital period which is just over 20 minutes. This, and other properties of this system make it one of the best in the list “testing” sources of gravitational waves for the future space interferometer LISA. Preprint published on the portal arXiv.org.
The project LISA (Laser Interferometer Space Antenna) is being developed jointly by the European space Agency and NASA, it represents a new stage of development of gravitational wave astronomy. It’s a space laser interferometer, which will consist of three spacecraft forming an equilateral triangle with sides of 1.5 million kilometers. The principle of operation of LISA is similar to ground-based observatories LIGO and Virgo, but it will be sensitive to waves of much lower frequency — operating range will be from 0.1 to 1 Hertz millihertz. In addition, the triangle scheme is L-shaped, which is used on Earth allows you to explore more properties of gravitational waves.
Currently, the program launch is planned for 2034, and the first season is estimated at five years. One of the main goals for LISA will search for gravitational waves from black holes of intermediate mass , or close double white dwarfs, the latter can be observed in the optical wavelength range, which now astronomers are conducting an active search for interesting objects of the interferometer.
A team of astronomers led by Warren brown (Warren Brown) reported the discovery of a close binary system of white dwarfs J2322+0509, located at a distance of 0.76 kiloparsec from the Sun. The orbital period of dwarfs around each other is 1201 second, which puts them in third place among the similar systems with the shortest orbital period. Originally a pair was found in the data directories of the space telescope Gaia and review SDSS (Sloan Digital Sky Survey), and then subjected to study using ground-based telescopes MMT (Multiple Mirror Telescope), the Gemini North and one of the Magellan telescopes.
The system is interesting because it consists of two helium white dwarfs with a mass of 0.27 and 0.24 solar masses, and the orientation of the plane of its orbit, which is visible almost flat, forming an angle with the line of sight of about 27 degrees, allows for greater 2.5 times of the signals of gravitational waves from the system than would be the case if J2322+0509 was visible from the edges. It is expected that six or seven million years dwarfs will merge into a single object. This makes the system one of the best in the list of “screening” system for LISA.
Earlier we told you about how LISA will find planets from double white dwarfs and you will see the difference exotic compact objects from black holes at the Planck scale.