16 Lacertae

16 Lacertae

A light curve for EN Lacertae, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lacerta
Right ascension 22h 56m 23.62929s[2]
Declination +41° 36′ 13.9482″[2]
Apparent magnitude (V) 5.587±0.015[3]
Characteristics
Spectral type B2 IV[4] + F6–7 + F0[5]
Variable type β Cep[6] + Algol[7]
Astrometry
Radial velocity (Rv)−12.45±0.04[8] km/s
Proper motion (μ) RA: −1.188[2] mas/yr
Dec.: −4.290[2] mas/yr
Parallax (π)2.0692 ± 0.0865 mas[2]
Distance1,580 ± 70 ly
(480 ± 20 pc)
Absolute magnitude (MV)−2.67±0.14[3]
Orbit[9]
Period (P)12.0969 d
Eccentricity (e)0.0539±0.0026
Periastron epoch (T)61.4±2.1
Semi-amplitude (K1)
(primary)		23.85±0.05 km/s
Details[3]
16 Lac A
Mass9.5±0.03 M☉
Radius5.6±0.4 R☉
Luminosity7,762+1,151
−1,002 L☉
Surface gravity (log g)3.95±0.05 cgs
Temperature23,000±200 K
Metallicity [Fe/H]0.00±0.08[10] dex
Rotational velocity (v sin i)12±1[10] km/s
Other designations
16 Lac, EN Lac, BD+40° 4949, HD 216916, HIP 113281, HR 8725, SAO 52512[11]
Database references
SIMBADdata

16 Lacertae is a triple star[5] system in the northern constellation of Lacerta, located about 1,580[2] light years from the Sun. It has the variable star designation EN Lacertae; 16 Lacertae is the Flamsteed designation. This system is visible to the naked eye as a faint blue-white hued star with a maximum apparent visual magnitude of +5.587.[3] It is moving closer to the Earth with a heliocentric radial velocity of –12 km/s.[8]

The binary nature of the brighter component was discovered in 1910 by astronomer Oliver J. Lee at Yerkes Observatory. The first orbital elements were published by Otto Struve and Nicholay T. Bobrovnikov in 1925.[12] This is a single-lined spectroscopic binary with an orbital period of 12.1 days and a small eccentricity of 0.05. It forms an eclipsing binary variable, although only the eclipse of the primary component has been detected. This component is a Beta Cephei variable star with three dominant pulsation modes having frequencies of around six per day.[6] It has a stellar classification of B2 IV,[4] matching a B-type subgiant star with 9.5 times the mass of the Sun and 5.6 times the Sun's radius.[3]

The unseen secondary is an F-type star of class F6–7. The tertiary component is a magnitude 11.4 star with a class of F0. As of 2008, it was located at an angular separation of 27.6″ from the primary.[5]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference gaia_dr2 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference nieva2014 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Lesh1968 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Jerzykiewicz2015 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Lehmann2001 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference nieva2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Struve1925 was invoked but never defined (see the help page).