| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lacerta |
| Right ascension | 22h 52m 02.03323s[1] |
| Declination | +43° 18′ 44.7028″[1] |
| Apparent magnitude (V) | 4.95[2] + 11.9[3] |
| Characteristics | |
| Spectral type | M0 III[4] |
| B−Vcolor index | 1.559±0.010[2] |
| Astrometry | |
| Radial velocity (Rv) | −19.21±0.20[2] km/s |
| Proper motion (μ) | RA: +109.890±0.214[1]mas/yr Dec.: +23.581±0.215[1]mas/yr |
| Parallax (π) | 9.6841±0.1425 mas[1] |
| Distance | 337 ± 5 ly (103 ± 2 pc) |
| Absolute magnitude (MV) | −0.04[2] |
| Details | |
| Radius | 37.30+0.61 −1.02[1] R☉ |
| Luminosity | 294.5±5.1[1] L☉ |
| Surface gravity (log g) | 1.352[5] cgs |
| Temperature | 3,915+55 −32[1] K |
| Other designations | |
| 15 Lac,BD+42° 4521,GC 31896,HD 216397,HIP 112917,HR 8699,SAO 52436,WDS J22520+4319[6] | |
| Database references | |
| SIMBAD | data |
15 Lacertae is abinary star[7] system in the northernconstellation ofLacerta, near the southeast constellation border withAndromeda. It is faintly visible to the naked eye with anapparent visual magnitude of 4.95.[2] The distance to this system is approximately 337 light years based onparallax.[1] It is drifting closer to theSun with aradial velocity of −19 km/s.[2] Theabsolute magnitude of 15 Lacertae is −0.04.[2]
The primary component is an agingred giant with astellar classification of M0 III.[4] With the supply of hydrogen at itscore exhausted, the star has cooled and expanded to 37 times theSun's radius. It is radiating 295 times theluminosity of the Sun from its swollenphotosphere at aneffective temperature of 3,915 K,[1] giving it a reddish hue.
The secondary companion was discovered by American astronomerS. W. Burnham in 1888. It has a visual magnitude of 11.9 and is located at anangular separation of23.6″ from the primary along aposition angle of 159°, as of 2014.[3]
