A-type star in the context of Diffraction grating

Beta Crateris, Latinized from β Crateris, is a binary star system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46. Based upon an annual parallax shift of 9.59 mas as seen from Earth, it is around 340 light years from the Sun.

This is an astrometric binary star system with an orbital period of 6.0 years and a projected separation of 8.3 AU. The orbit has an estimated semimajor axis of 9.3 AU. The primary component A is listed as an A-type giant star with a stellar classification of A2 III. However, Houk and Smith-Moore (1988) give a main sequence classification of A1 V, while Abt and Morrell (1995) list it as a subgiant star with a class of A2 IV. The spectrum shows enhanced barium, possibly as a result of a previous mass transfer event.

SS 433 is a microquasar or eclipsing X-ray binary system, consisting of a stellar-mass black hole accreting matter from an A-type companion star. SS 433 is the first discovered microquasar. It is at the centre of the supernova remnant W50.

SS 433's designation comes from the initials of two astronomers at Case Western Reserve University: Nicholas Sanduleak and Charles Bruce Stephenson. It was the 433rd entry in their 1977 catalog of stars with strong emission lines. Its emission lines were studied by Mordehai Milgrom in 1979.

Mu Serpentis, Latinized from μ Serpentis, is a binary star in the Serpens Caput (head) section of the equatorial constellation Serpens. It is visible to the naked eye with an apparent visual magnitude of 3.543. Based upon an annual parallax shift of 19.23 mas as seen from Earth, it is located around 170 light years from the Sun.

This is an astrometric binary for which coarse orbital elements have been determined based on interferometric observations. The pair orbit each other with a period of around 36 years and an eccentricity of roughly 0.4. The primary member, component A, is a white-hued A-type main sequence star with a stellar classification of A0 V. The nature of the secondary, component B, is less certain – it may be a class A or F type star of unknown luminosity class.

HD 256 is a binary star system in the equatorial constellation of Cetus. It has a white hue and is dimly visible to the naked eye with an apparent visual magnitude of 6.20. Based upon parallax measurements, the system is located at a distance of approximately 474 light years from the Sun. It is drifting closer with a radial velocity of −10 km/s.

Originally considered a single star, it was reported to be a shell star in 1982. Circumstellar absorption lines were then found to be variable, showing a similarity to the edge-on debris disk surrounding Beta Pictoris. The stellar classification of A2 IV/V matched an A-type star near the end of its main sequence lifetime, showing traits of an emerging subgiant star phase.

Rho Virginis (ρ Vir, ρ Virginis) is the Bayer designation for a star in the constellation Virgo. It has an apparent visual magnitude of +4.9, making it a challenge to view with the naked eye from an urban area (according to the Bortle Dark-Sky Scale). The distance to this star has been measured directly using the parallax method, which places it 118.3 light-years (36.3 parsecs) away with a margin of error of about a light year.

Rho Virginis is an A-type main sequence star with a stellar classification of A0 V. It is larger than the Sun with a radius 60% larger and about twice the mass. As such it is generating energy at a higher rate than the Sun, with a luminosity 14 times greater. The outer atmosphere has an effective temperature of 8,930 K, which is what gives it the white-hued glow of an A-type star. It is classified as a Delta Scuti type variable star and its brightness varies by 0.02 magnitudes over periods of 0.5 to 2.4 hours.

Phi Leonis (φ Leo) is a single star in the equatorial-northern constellation Leo, located in the southern celestial hemisphere. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of 4.46. Based upon parallax measurements, the distance to Phi Leo is around 184 light years.

The spectrum of this star fits a stellar classification of A7IVn, which suggests it is an A-type subgiant star that has left the main sequence and is evolving into a giant star. It is being viewed with the plane of the star's equator lying close the line of sight from the Earth, and shows a high rotation rate with a projected rotational velocity of 254 km/s. This rapid spin is giving the star an oblate shape with an equatorial bulge that is 29% larger than the polar radius.

35 Aquilae (abbreviated 35 Aql) is a star in the equatorial constellation of Aquila. 35 Aquilae is its Flamsteed designation though it also bears the Bayer designation c Aquilae. The apparent visual magnitude of this star is 5.8, which means it is a faint star but visible to the naked eye from dark suburban or rural skies. It has an annual parallax shift of 16.34 mas that is caused by the Earth's orbit around the Sun. This yields a distance estimate of 200 light-years (61 parsecs), give or take a 4 light-year margin of error. At this distance, the visual magnitude is diminished by 0.26 from extinction caused by interstellar gas and dust.

The spectrum of 35 Aquilae fits a stellar classification of A0 V, indicating it is an A-type main sequence star. Compared to the Sun, it has 210% of the mass and 180% of the radius. As such, it is much brighter than the Sun, emitting 14 times the luminosity from its outer atmosphere at an effective temperature of 8,939 K. This heat causes it to glow with the white-hot hue of an A-type star. 35 Aquilae is spinning rapidly with a projected rotational velocity of 110 km/s.