HD 198716

HD 198716
HD 198716 is the star circled in red
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 20h 53m 40.18538s[1]
Declination −39° 48′ 35.5092″[1]
Apparent magnitude (V) 5.33±0.01[2]
Characteristics
Spectral type K2 III[3]
B−V color index +1.32[4]
Astrometry
Radial velocity (Rv)20.1±2.8[5] km/s
Proper motion (μ) RA: +43.548 mas/yr[1]
Dec.: −97.023 mas/yr[1]
Parallax (π)8.2435 ± 0.0774 mas[1]
Distance396 ± 4 ly
(121 ± 1 pc)
Absolute magnitude (MV)−0.1[6]
Details
Mass2.45±0.12[7] M☉
Radius23.9[8] R☉
Luminosity160±3[1] L☉
Surface gravity (log g)1.41±0.01[9] cgs
Temperature4,453±122[10] K
Metallicity [Fe/H]−0.04[11] dex
Rotational velocity (v sin i)2±1.3[12] km/s
Age622+275
−64[1] Myr
Other designations
33 G. Microscopii[13], CD−40°14078, CPD−40°9399, GC 29127, HD 198716, HIP 103127, HR 7987, SAO 212522[14]
Database references
SIMBADdata

HD 198716, also known as HR 7987 or 33 G. Microscopii, is a solitary star[15] located in the southern constellation Microscopium. Eggen (1993) lists it as a member of the Milky Way's old disk population.[11]

The object has an apparent magnitude of 5.33,[2] making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia satellite, it is estimated to be 396 light years away from the Solar System.[1] However, it is drifting closer with a somewhat constrained heliocentric radial velocity of 20 km/s.[5] At its current distance, HD 198716's brightness is diminished by 0.1 magnitude due to interstellar dust.[16]

This is an evolved red giant star with a stellar classification of K2 III. It has 2.45 times the mass of the Sun[7] but at an age of 622 million years,[1] it has expanded to 23.9 times the Sun's radius.[8] It radiates 160 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 4,453 K,[10] giving it an orange hue. HD 198716 is slightly metal deficient and spins moderately with a projected rotational velocity of 2 km/s.[12]

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Houk1982 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Kervella2019 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Kervella2021 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Poggio2022 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Eggen1993 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference DeMed2014 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).