Spica: Virgo’s Brightest Star
Spica, also known as Alpha Virginis, is the brightest star in the constellation Virgo. Sky Tonight will help you find Spica in the sky, and here you’ll learn some facts about this star.
Contents
- Spica: key facts
- How to find Spica
- When to see Spica
- Virgo’s brightest star Spica is, in fact, 2 stars
- More facts about Spica
- Bright star Spica: bottom line
Spica: key facts
- Official names: Spica, Alpha Virginis, α Vir
- Alternative names: Azimech, Spica Virginis
- Catalog designations: 67 Virginis, HD 116658, HIP 65474, HR 5056
- Constellation: Virgo
- Star type: binary star system
- Right ascension: 13h 25m 11.58s
- Declination: −11° 09′ 40.8″
- Apparent magnitude: 1.0
- Mass: 11.43 solar masses
- Luminosity: 20,512 L
- Radius: 7.47 solar radius
- Surface temperature: 20,900 K
- Distance from the Earth: 250 light-years
- Rotation period: 4 days
How to find Spica
The blue-white star Spica in the constellation Virgo is bright enough (mag 1.0) to be seen with the naked eye. Here's what can help you find Spica’s location.
Use the Big Dipper
One way to locate Spica is by using the Big Dipper – one of the most recognizable star patterns in the sky. Extend the curve of the Big Dipper's handle to find Arcturus, and then continue the line roughly as far again to reach Spica. There’s a mnemonic rule to remember this technique: “Arc to Arcturus and spike to Spica”.
Use the stargazing apps
Another convenient way to find Spica is by using a stargazing app like Sky Tonight. It provides real-time information about celestial objects and their locations. With this free app, you can find Spica in a few simple steps:
- Open the app’s search bar and type “Spica.”
- Tap the blue target button to the right of the matching result. The app will show you the star's position on the sky map.
- Tap the blue compass button at the bottom right of the screen. The app will use your device’s location to align the screen image with the real sky above you.
- Follow the white arrow until you see Spica on the screen and in the real sky.
When to see Spica
As a part of a zodiac constellation, Spica can be seen in the sky during certain months. The best time to observe the star is from March to late June. Keep in mind that from mid-September to the end of October, the Sun visits Virgo, so Spica is in the sky during the daytime.
Observe Spica next to the Moon
Spica is close to the ecliptic, so from time to time, it meets the Moon and planets. Let’s see when the star will be next to the Moon.
April 23, 2024
On April 23, at 02:02 GMT (April 22, 10:02 p.m. EDT), the Moon and Spica will share the same right ascension. The apparent distance between the two objects will be 1°36'. The duo will be in the sky from dusk till dawn, rising highest by midnight.
May 20, 2024
On May 20, at 09:20 GMT (5:20 a.m. EDT), the Moon and Spica will share the same right ascension. The apparent distance between the two objects will be 1°30'. Find both objects in the evening sky after sunset.
June 16, 2024
On June 16, at 17:28 GMT (1:28 p.m. EDT), the Moon and Spica will share the same right ascension. The apparent distance between the two objects will be 1°18'. The duo will be the highest in the sky right after sunset.
July 14, 2024
On July 14, at 01:48 GMT (July 13, 9:48 p.m. EDT), the Moon and Spica will share the same right ascension, with an apparent distance of 1°. Observe both objects after sunset.
August 10, 2024
On August 10, at 09:34 GMT (5:34 a.m. EDT), the Moon and Spica will share the same right ascension, with an apparent distance of 0°48'. Both objects will be visible for a couple of hours after sunset.
You can often see bright dots near the Moon. Apart from Spica, these could be other bright objects, such as Venus or Jupiter. To stay updated on when the Moon meets the planets, read our dedicated article.
You can also check the “Events” tab in the Sky Tonight’s calendar from time to time: there, you can find a lot of useful information about everything that happens in the night sky (watch our video and see for yourself).
Virgo’s brightest star Spica is, in fact, 2 stars
Spica is not an individual star: it is a binary star system, that consists of two stars known as Spica A and Spica B. These stars orbit each other so close that they can’t even be resolved as two stars through a telescope. Also, their mutual gravity distorts them into an oval shape.
Spica A
Spica A is the larger and more massive star of the pair. It is a blue-white giant star that shines with a luminosity over 2,000 times that of our Sun: 80% of the light in the star system comes from Spica A. With a diameter approximately 10 times larger than the Sun, Spica A is an impressive celestial body.
Spica B
Spica B is a smaller and less massive component of the star system. It is a blue-white main-sequence star, meaning it is still in the process of burning hydrogen in its core. Although smaller than Spica A, Spica B is still seven times larger than our Sun.
More facts about Spica
Bright star in the night sky
Spica is the brightest star in the constellation Virgo. Also, it is ranked as the 15th brightest star overall (or 16th, if you count the Sun).
Ear of grain in Virgo’s hand
The name “Spica” comes from the Latin word for “ear of grain”, as it represents a single stalk of wheat held by Demeter – the goddess of agriculture in Greek mythology, which was associated with the constellation Virgo.
Guiding star
Spica is listed among 57 navigational stars. Due to its brightness and proximity to the ecliptic, Spica is often used as a navigational reference point for spacecraft and satellites.
Part of the Spring Triangle and the Great Diamond
Spica is part of the two asterisms: the Spring Triangle (along with Arcturus in the constellation Bootes and Regulus in the constellation Leo), and the Great Diamond (along with Arcturus in the constellation Bootes, Denebola in the constellation Leo, and Cor Caroli in Canes Venatici).
Bright star Spica: bottom line
Spica is the brightest star in the constellation Virgo. It can be easily observed in the night sky from March to late June. You can locate Spica by using the Big Dipper or stargazing apps, like Sky Tonight. Also, Spica can sometimes be found near the Moon.
