Alya is a three-star system in the constellation Serpens. The primary and secondary stars (also known as Theta A and Theta B) are pale yellow in color; the third star in the system is dimmer, with an apparent magnitude of around 6.
As you look upon Alya, keep in mind Theta A and B are spinning at a very high rate of speed. Specifically, Theta A spins at 141 kilometers per second (315,000 MPH), while Theta B is rotating a whopping 217 kilometers per second (485,000 MPH)! A bullet travels around 1,800 MPH, the earth at 1,000 MPH, and our sun rotates at about 4,500 MPH). It’s impossible to really imagine how fast these stars are turning.
My Observations
| Date | June 25, 2021 |
| Time | 11:30 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Average |
| Transparency | Above Average |
Alya is a nice double star. The two stars appear very close in magnitude in my scope and appear yellow. The secondary star seems to have a greenish tinge to it. Granted, no stars are green, so perhaps its dimmer appearance gives me the hue. Also notable is the field of stars surrounding the double. Alya lies in a bed of fainter stars, leaving a nice impression for the observer.
Key Stats
| Constellation | Serpens |
| Best Viewing | Summer |
| Visual Magnitude | +4.9 | +4.6 |
| Absolute Visual Magnitude | +1.2 |
| Distance from Earth | 155 ly |
| Separation | 22.5″ | 1070 AU |
| Orbital Period | Unknown |
| Milky Way Location | Orion Spur |
| My Viewing Grade | A- |
Sources and Notes
Banner photo from the ESO Online Digitized Sky Survey.
Sketch by Wayne McGraw
AKA: θ Serpentis, Theta Ser, SAO 124068
The Garden Astronomer 