15 Lacertae
Star in the constellation Lacerta
From Wikipedia, the free encyclopedia
15 Lacertae is a binary star[9] system in the northern constellation of Lacerta, near the southeast constellation border with Andromeda. It is faintly visible to the naked eye with an apparent visual magnitude of 4.95.[2] The distance to this system is approximately 337 light years based on parallax.[1] It is drifting closer to the Sun with a radial velocity of â19 km/s.[2] The absolute magnitude of 15 Lacertae is â0.04.[2]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lacerta |
| Right ascension | 22h 52m 02.03323s[1] |
| Declination | +43° 18â² 44.7028â³[1] |
| Apparent magnitude (V) | 4.95[2] + 11.9[3] |
| Characteristics | |
| Spectral type | M0 III[4] |
| BâV color index | 1.559±0.010[2] |
| Astrometry | |
| Radial velocity (Rv) | â19.21±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 (Ï) | 9.6841±0.1425 mas[1] |
| Distance | 337 ± 5 ly (103 ± 2 pc) |
| Absolute magnitude (MV) | â0.04[2] |
| Details | |
| Mass | 1.3[5] Mâ |
| Radius | 35[6] Râ |
| Luminosity | 269[6] Lâ |
| Surface gravity (log g) | 1.79[5] cgs |
| Temperature | 4,047[5] K |
| Metallicity [Fe/H] | â0.22[5] dex |
| Age | 12.7[7] Gyr |
| Other designations | |
| 15 Lac, BD+42°4521, GC 31896, HD 216397, HIP 112917, HR 8699, SAO 52436, WDS J22520+4319[8] | |
| Database references | |
| SIMBAD | data |
The primary component is an aging red giant with a stellar classification of M0 III.[4] With the supply of hydrogen at its core exhausted, the star has cooled and expanded to 35 times the Sun's radius.[6] It is radiating 269 times the luminosity of the Sun[6] from its swollen photosphere at an effective temperature of 4,047 K[5] giving it a reddish hue.
The secondary companion was discovered by American astronomer S. W. Burnham in 1888. It has a visual magnitude of 11.9 and is located at an angular separation of 23.6Ⳡfrom the primary along a position angle of 159°, as of 2014.[3]