45 Herculis

45 Herculis

An ultraviolet band light curve for V776 Herculis, adapted from Burke and Barr (1981)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 16h 47m 46.41942s[2]
Declination +05° 14′ 48.2789″[2]
Apparent magnitude (V) 5.22[3]
Characteristics
Spectral type A1 Vp Si[4] or B9p Cr[5]
U−B color index +0.005[6]
B−V color index −0.025[6]
Variable type α2 CVn[7]
Astrometry
Radial velocity (Rv)−13.13±0.09[8] km/s
Proper motion (μ) RA: −18.802[2] mas/yr
Dec.: −38.735[2] mas/yr
Parallax (π)8.1955 ± 0.2169 mas[2]
Distance400 ± 10 ly
(122 ± 3 pc)
Absolute magnitude (MV)−0.18[9]
Orbit[8]
Period (P)99.51 ± 0.10 d
Eccentricity (e)0.445 ± 0.020
Argument of periastron (ω)
(primary)		167.1 ± 4.2°
Semi-amplitude (K1)
(primary)		4.75 ± 0.12 km/s
Details
Mass2.85±0.11[10] M☉
Radius4.3[11] R☉
Luminosity129.7[8] L☉
Surface gravity (log g)3.55[12] cgs
Temperature9,400[8] K
Metallicity [Fe/H]0.10[12] dex
Rotation4.116476 ± 0.000022
Rotational velocity (v sin i)35.5[13] km/s
Age351–469[8] Myr
Other designations
l Her, 45 Her, V776 Herculis, BD+05°3272, HD 151525, HIP 82216, HR 6234, SAO 121865, WDS 16478+0515[14]
Database references
SIMBADdata

45 Herculis is a binary variable star in the northern constellation Hercules. It has the Bayer designation l Herculis and the variable star designation V776 Herculis. The Flamsteed designation for this star comes from the publication Historia Coelestis Britannica by John Flamsteed. It is the 45th star in Flamsteed list of stars in the constellation Hercules, and is visible to the naked eye with a baseline apparent visual magnitude of 5.22.[3] Parallax measurements show this star to be about 400 light-years away from the Solar System.[2] It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[15]

Cowley et at. (1969) assigned this object a classification of B9p Cr,[5] while Abt and Morrell (1995) found a class of A1 Vp Si.[4] Both indicate this is a late B- or early A-type chemically peculiar, or Ap star, with abundance anomalies in chromium or silicon. It is classified as a magnetic Ap star, although its magnetic field is unusually weak for a star of this class.[8] It is an Alpha2 Canum Venaticorum variable that ranges in visual magnitude from 5.21 down to 5.27.[7] The star has 2.9[10] times the mass of the Sun and 4.9[11] times the Sun's radius. It is radiating 120[9] times the Sun's luminosity from its photosphere at an effective temperature of 9,333 K.[12]

Although 45 Herculis was long thought to be a solitary star,[16] a 2023 study confirmed that 45 Herculis is a single-lined spectroscopic binary. The pair of stars orbit each other every 99.51 days on a moderately eccentric orbit. The secondary star is likely a low-mass star.[8]

  1. ^ Cite error: The named reference Burke was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Ducati was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference abt1995 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference EgUBV was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  8. ^ a b c d e f g Kochukhov, O.; Gürsoytrak Mutlay, H.; Amarsi, A. M.; Petit, P.; Mutlay, I.; Gürol, B. (2023). "Surface structure of 45 Hercules: An otherwise unremarkable Ap star with a surprisingly weak magnetic field". Monthly Notices of the Royal Astronomical Society. 521 (3): 3480–3499. arXiv:2303.03862. Bibcode:2023MNRAS.521.3480K. doi:10.1093/mnras/stad720.
  9. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Martin2017 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference shulyak2014 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference Wolff1967 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Royer2002 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 GCRV was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).