4 Equulei (HIP 104101)

4 Equulei is a yellow-white main-sequence star in the constellation Equuleus. It lies about 146 light years away. It is moving through the Galaxy at a speed of 41.8 km/s relative to the Sun.

Sky position: RA 21h 5.4m, Dec +5° 57.5'

Common designations: 4 Equulei, HR 8077, HD 200790, Gaia DR3 1736325127380047744, HIP 104101

4 Equulei has the spectral type F8V. F-type stars are yellow-white stars of about 6,000 to 7,500 K, slightly hotter and more massive than the Sun. Their hydrogen lines are weaker than in A stars and metal lines become prominent. Its luminosity class V means it is a main-sequence (dwarf) star, still fusing hydrogen into helium in its core like the Sun.

How to find 4 Equulei in the sky

4 Equulei lies in Equuleus. With a declination of +5° 57.5', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 84° S. It is highest in the sky at local midnight around September, which makes the weeks around that month the best time to observe it.

Tabulated data for 4 Equulei

Astrometry and spectroscopy

Right Ascension (J2000)	316.36126514° (21h 5.4m)
Declination (J2000)	5.95830122° (+5° 57.5')
Galactic Longitude	55.38341785°
Galactic Latitude	-26.18388160°
Proper motion RA	-58.67 mas/yr
Proper motion Dec	-157.65 mas/yr
Parallax	22.30 ± 0.77 mas
Spectral Type	F8V
Radial Velocity	-21.71 km/s

Photometry

Band	Magnitude	Abs. Mag.
R	5.60	2.34
J	4.85	1.59
H	4.69	1.43
K	4.58	1.32

Derivations

Heliocentric distance: 44.85 pc (146 light years) (3.4% margin of error)
Transverse velocity: 35.8 km/s
Space velocity relative to the Sun: 41.8 km/s
Galactic position (X, Y, Z): 22.9 pc, 33.1 pc, -19.8 pc
Galactic velocity (U, V, W): 15.4 km/s, -38.9 km/s, 1.9 km/s

Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.