HD 5608

HD 5608
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Andromeda
Right ascension 00h 58m 14.21894s[1]
Declination +33° 57′ 03.1841″[1]
Apparent magnitude (V) +5.98[2]
Characteristics
Evolutionary stage Red giant branch[3]
Spectral type K0 IV[4]
B−V color index 1.016[2]
Astrometry
Radial velocity (Rv)−23.13±0.12[1] km/s
Proper motion (μ) RA: 36.459 mas/yr[1]
Dec.: -71.320 mas/yr[1]
Parallax (π)17.0697 ± 0.0302 mas[1]
Distance191.1 ± 0.3 ly
(58.6 ± 0.1 pc)
Absolute magnitude (MV)+2.11[4]
Orbit[5]
Period (P)146+74
−37 yr
Semi-major axis (a)0.524+0.151
−0.084"
(30.7+8.8
−4.9 AU)
Eccentricity (e)0.53+0.18
−0.26
Inclination (i)147.5+6.6
−13°
Longitude of the node (Ω)141+56
−48°
Periastron epoch (T)2,472,895+17,464
−5,098
Argument of periastron (ω)
(secondary)		257+32
−35°
Details[6]
HD 5608 A
Mass1.50±0.04 M☉
Radius5.0±0.1 R☉
Luminosity13.1±0.3 L☉
Surface gravity (log g)3.20±0.02 cgs
Temperature4,897±25 K
Metallicity [Fe/H]+0.12±0.03[3] dex
Rotational velocity (v sin i)1.37[4] km/s
Age3.0±0.3 Gyr
HD 5608 B
Mass0.10±0.01[7] M☉
Mass121.2+8.3
−7.0[5] MJup
Other designations
BD+33° 140, FK5 2061, HD 5608, HIP 4552, HR 275, SAO 54306[8]
Database references
SIMBADdata

HD 5608 is an orange-hued star in the northern constellation of Andromeda with one known planet, HD 5608 b.[4] It is a dim star near the lower limit of visibility to the naked eye, having an apparent visual magnitude of +5.98.[2] The distance to HD 5608, as estimated from an annual parallax shift of 17.07 mas,[1] is 191 light-years (59 parsecs). It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s,[1] and is expected to make its closest approach in 1.285 million years when it comes to within 124 light-years.[9]

This is a K-type subgiant star on the red giant branch track with a stellar classification of K0 IV.[4] It has 1.5 times the mass of the Sun and, at the age of three billion years, has expanded to five times the Sun's radius. It is radiating 13 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,897 K. It has a higher than solar metallicity – a term astronomers use to describe the abundance of elements other than hydrogen and helium.[6]

HD 5608 has a co-moving companion, HD 5608 B, at an angular separation of 0.6″, which has been directly imaged. The physical separation of the pair is calculated as 40±1 AU or 47±3 AU, depending on the assumptions. It has an H band magnitude difference of 9.40 with the primary and an estimated mass of 0.10 M☉. A second companion at a separation of 7.4″ is a background star.[7] This companion star has since been characterized by radial velocity and astrometry in addition to imaging.[5]

  1. ^ a b c d e f g Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference TYCHO was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Stock2018 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Sato2012 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Teng2023 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Bonfanti2016 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Ryu2016 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).