11 Cephei

11 Cephei
Observation data
Epoch J2000      Equinox J2000
Constellation Cepheus
Right ascension 21h 41m 55.31069s[1]
Declination +71° 18′ 41.2585″[1]
Apparent magnitude (V) 4.55[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K0.5 III[4]
B−V color index 1.108±0.004[2]
Astrometry
Radial velocity (Rv)−38.36±0.19[2] km/s
Proper motion (μ) RA: +111.130[1] mas/yr
Dec.: +92.743[1] mas/yr
Parallax (π)17.6830 ± 0.1814 mas
Distance184 ± 2 ly
(56.6 ± 0.6 pc)
Absolute magnitude (MV)0.16[2]
Details[5]
Mass2.38±0.07 M☉
Radius10.93+0.27
−0.26 R☉
Luminosity94.9±8.8 L☉
Surface gravity (log g)2.41 cgs
Temperature5,446±113 K
Metallicity [Fe/H]0.17 dex
Rotational velocity (v sin i)1.0[6] km/s
Age670±60 Myr
Other designations
11 Cep, BD+70°1193, FK5 817, HD 206952, HIP 107119, HR 8317, SAO 10126[7]
Database references
SIMBADdata

11 Cephei is a single[8] star in the northern constellation of Cepheus,[7] located 184 light years away from the Sun.[1] It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.55.[2] The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.153 arc seconds per annum.[9] It is moving closer to the Earth with a heliocentric radial velocity of −38 km/s.[2]

This is an aging giant star with a stellar classification of K0.5 III,[4] having exhausted the hydrogen at its core and expanded. It is a red clump giant, which means it is currently on the horizontal branch and is generating energy through helium fusion at the core.[3] 11 Cephei is 670 million years old with 2.4 times the mass of the Sun and 11 times the Sun's radius. It is radiating around 95 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 5,446 K.[5]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Alves2000 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Baines2018 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference DeMedeiros2000 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Lepine2005 was invoked but never defined (see the help page).