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Swift J010902.6-723710 is a Be/X-ray binary system detected by the Swift Small Magellanic Cloud (SMC) Survey (S-CUBED). An X-ray outburst, detected on October 10, 2023, had characteristics of Type I and II outbursts. Proposed orbital period is 60.623 days. Companion star of the system is "B0-0.5 star of spectral class Ve".
Red dwarfs, also referred to as class M stars, are stars of 0.08–0.40 M ☉. They have sufficient mass to sustain hydrogen -to- helium fusion via the proton–proton chain reaction , but they do not have sufficient mass to create the temperatures and pressures necessary to fuse helium into carbon , nitrogen or oxygen (see CNO cycle ).
X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the donor (usually a relatively common main sequence star ), to the other component, called the accretor , which is either a neutron star or black hole .
Their surface gravity is typically between 10 4 and 10 6 meters per second squared. Some PG 1159 stars are still fusing helium. [3], § 2.1.1, 2.1.2, Table 2. The PG 1159 stars are named after their prototype, PG 1159-035. This star, found in the Palomar-Green survey of ultraviolet-excess stellar objects, [4] was the first PG 1159 star discovered.
GRB 221009A is only the seventh gamma-ray burst known to have generated these rings, [10] and as of March 2023, a record twenty X-ray afterglow rings had been identified around the burst, triple the previous record. [45] [10] The afterglow of GRB 221009A was the brightest ever recorded, beating the record of GRB 030329. [46]
The plane of incidence is defined by the incoming radiation's propagation vector and the normal vector of the surface. In describing reflection and refraction in optics, the plane of incidence (also called the incidence plane or the meridional plane [citation needed]) is the plane which contains the surface normal and the propagation vector of the incoming radiation. [1]
The principal ray or chief ray (sometimes known as the b ray) in an optical system is the meridional ray that starts at an edge of an object and passes through the center of the aperture stop. [5] [8] [7] The distance between the chief ray (or an extension of it for a virtual image) and the optical axis at an image location defines the size of ...
Geometrical optics, or ray optics, is a model of optics that describes light propagation in terms of rays.The ray in geometrical optics is an abstraction useful for approximating the paths along which light propagates under certain circumstances.