Mu Lyrae

Mu Lyrae

Observation data Epoch J2000      Equinox J2000
Constellation	Lyra
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	5.11
Characteristics
Evolutionary stage	subgiant
Spectral type	A3IVn
U−B Template:Engvar	+0.07
B−V Template:Engvar
Astrometry
Radial velocity (Rv)	km/s
Proper motion (μ)	RA:  mas/yr Dec.:  mas/yr
Parallax (π)	7.9161±0.1438 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	–0.53
Details
Mass	Template:Solar mass
Radius	Template:Solar radius calculator0Template:Efn (oblate) Template:Solar radius
Luminosity	Template:Solar luminosity
Temperature	K
Rotational velocity (v sin i)	165 km/s
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data

μ Lyrae, Latinized as Mu Lyrae, is a solitary star in the northern constellation Lyra. It has the traditional name Alathfar Template:IPAc-en, from the Arabic الأظفار al-ʼaẓfār "the talons (of the swooping eagle)", a name it shares with Eta Lyrae (though the latter is spelled "Aladfar" by the IAU). This white-hued object is visible to the naked eye as faint point of light with an apparent visual magnitude of 5.11. It is located approximately 412 light years distant from the Sun based on parallax, but is drifting closer with a radial velocity of −24 km/s.

This object has evolved off the main sequence, becoming a subgiant with a stellar classification of A0 IV. It has a fairly high rate of spin, showing a projected rotational velocity of 165 km/s. This is giving the star an equatorial bulge that is an estimated 17% larger than the polar radius. The star has three times the mass of the Sun and about 5.8 times the Sun's radius. It is radiating 200 times the Sun's luminosity from its photosphere at an effective temperature of 9,016 K.