HD 51418

HD 51418 (NY Aurigae) is an Ap star and an α² CVn variable located about 178 parsecs (580 ly) away in the northern constellation of Auriga. With an apparent magnitude of 6.67 and a spectral type of A0, it can be faintly visible by the naked eye as a whitish dot under very good circumstances. The star has been noted as an "extreme lanthanide star,"^[6] with an overabundance of metals including europium, dysprosium, and holmium, which can be observed in the star's spectra as emission lines.^[2][7]

A light curve for NY Aurigae, plotted from Hipparcos data^[8]

HD 51418

Location of HD 51418 (circled)
Observation data Epoch J2000.0[1]      Equinox J2000.0[1]
Constellation	Auriga
Right ascension	06h 59m 20.12818s[1]
Declination	+42° 18′ 53.1147″[1]
Apparent magnitude (V)	6.67
Characteristics
Spectral type	A0 SrCrEuDy,[2] A0pEuSrCrMgII[3]
B−V color index	0.09[1]
J−H color index	-0.087[1]
J−K color index	-0.037[1]
Variable type	α2 CVn variable[2]
Astrometry
Radial velocity (Rv)	−22.5±3.0[4] km/s
Proper motion (μ)	RA: -1.210[1] mas/yr Dec.: −6.792[1] mas/yr
Parallax (π)	5.6092±0.0929 mas[1]
Distance	581 ± 10 ly (178 ± 3 pc)
Details
Mass	3.557±0.178[5] M☉
Radius	3.297±0.165[5] R☉
Other designations
AG+42° 775, BD+42°1629, Gaia DR2 951315950188279424, GC 9158, HD 51418, HIP 33643, SAO 41475, PPM 49494, TIC 192072521, TYC 2950-1335-1, GSC 02950-01335, 2MASS J06592013+4218531, NY Aur, Renson 14180[1]
Database references
SIMBAD	data

In 1972, Austin F. Gulliver et al. announced that HD 51418 is a variable star.^[9] It was given its variable star designation, NY Aurigae, in 1975.^[10] HD 51418 possesses a strong magnetic field, which fluctuates in strength between −22–75 milliteslas (−220–750 G).^[11] The magnetic minimum is known to occur concurrently with the minimums in luminosity and rare-earth detection.^[7]

Visual companion

Speckle imaging observations conducted in 2009 revealed a previously unresolved companion star at a separation of 0.15 arcseconds. The secondary star, component "B" of the double star WDS 06593+4219 as designated in the Washington Double Star Catalog, is an F-type star with an apparent magnitude of 10.0.^[12][13]

See also

• Przybylski's Star
• GY Andromedae