3 Piscis Austrini

3 Piscis Austrini
Location of 3 PsA (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 21h 13m 17.32730s[1]
Declination −27° 37′ 09.7106″[1]
Apparent magnitude (V) 5.39±0.01[2]
Characteristics
Spectral type K3 III[3]
B−V color index +1.42[4]
Astrometry
Radial velocity (Rv)−46.2±2.4[5] km/s
Proper motion (μ) RA: +98.513 mas/yr[1]
Dec.: −110.906 mas/yr[1]
Parallax (π)8.0734 ± 0.1733 mas[1]
Distance404 ± 9 ly
(124 ± 3 pc)
Absolute magnitude (MV)+0.19[6]
Details
Mass1.58[7] M☉
Radius31.3±1.6[8] R☉
Luminosity184+9
−8[1] L☉
Surface gravity (log g)1.86[9] cgs
Temperature4,225±123[10] K
Metallicity [Fe/H]−0.17[9] dex
Rotational velocity (v sin i)<1[11] km/s
Age2.59+0.83
−1.90[1] Gyr
Other designations
3 PsA, 58 G. Microscopii[12], CD−28°17178, CPD−28°7411, FK5 1556, GC 29652, HD 201901, HIP 104750, HR 8110, SAO 190129[13]
Database references
SIMBADdata

3 Piscis Austrini, also known as HD 201901 or simply 3 PsA, is an astrometric binary[14] (100% chance[15]) located in the southern constellation Microscopium. It was once part of Piscis Austrinus, the southern fish. The system has a combined apparent magnitude of 5.39,[2] making it faintly visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 404 light years[1] and it is currently approaching the Solar System with a heliocentric radial velocity of −46.2 km/s.[5] At its current distance, 3 PsA's brightness is diminished by 0.12 magnitudes due to extinction from interstellar dust[16] and it has an absolute magnitude of +0.19.[6]

The visible component is an evolved red giant with a stellar classification of K3 III.[3] The interferometry-measured angular diameter of the star, after correcting for limb darkening, is 2.03±0.04 mas,[17] which, at its estimated distance, equates to a physical radius of about 20 times the radius of the Sun.[18] However, its actual empirical radius is 31.3 R☉.[8] It has 1.58 times the mass of the Sun[7] and is radiating 184 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperature of 4,225 K.[10] 3 PsA is metal deficient with an iron abundance 68% that of the Sun ([Fe/H] = −0.17)[9] and it spins too slowly for its projected rotational velocity to be measured accurately.[11] It is estimated to be 2.59 billion years old based on Gaia DR3 models.[1]

  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. ^ a b 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. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference McWilliam1990 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 De Medeiros2014 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Frankowski2006 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).
  17. ^ Cite error: The named reference Richichi2005 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference lang2006 was invoked but never defined (see the help page).