8 Aquilae

Lore & Background

8 Aquilae has been assigned conflicting spectral classifications: Abt and Morrell (1995) classified it as F0 IV, indicating a subgiant, while Fox Machado et al. (2010) assigned F2 III, suggesting an evolved giant. Despite this, evolutionary models place the star near the end of its main sequence life, with an age of about a billion years. It has 1.6 times the Sun's mass and radiates 19 times the Sun's luminosity from its photosphere at an effective temperature of about 7,395 K.

The star's variability was discovered by Lester Fox Machado et al. during observations in 2003 and published in 2007. It is a Delta Scuti variable with at least three overlapping pulsation frequencies, though the total amplitude of its brightness variations is only about 0.02 magnitudes. It has a relatively high rotation rate, with a projected rotational velocity of 105 km/s.

8 Aquilae is moving further from Earth with a heliocentric radial velocity of +12 km/s. It can be viewed with the naked eye in good seeing conditions, appearing as a dim, yellow-white hued star with an apparent visual magnitude of 6.08.

Reader's Guide

8 Aquilae's significance lies in its classification as a low-amplitude Delta Scuti variable, a type of pulsating star that helps astronomers study stellar structure and evolution. The discovery of at least three overlapping pulsation frequencies in this star provides insight into the complex internal dynamics of F-type stars near the end of their main sequence life. The conflicting spectral classifications (F0 IV vs. F2 III) highlight the difficulty in precisely characterizing stars in transitional evolutionary stages, and the star's relatively high rotation rate of 105 km/s adds to its interest as a rapidly rotating variable. Its small amplitude of only 0.02 magnitudes makes it a challenging target for variability studies, yet it contributes to the broader understanding of Delta Scuti stars, which are important for asteroseismology. The star's visibility to the naked eye under good conditions also makes it accessible for amateur astronomers interested in monitoring variable stars. Its legacy is tied to the ongoing refinement of stellar models and the characterization of pulsation modes in intermediate-mass stars.

Did You Know?

• Its brightness variations have a total amplitude of only about 0.02 magnitudes.
• It is located 271 light years from the Sun and has an apparent visual magnitude of 6.08.