Beta1 Sagittarii

For other stars with this Bayer designation, see β Sagittarii.
Beta1 Sagittarii
Diagram showing star positions and boundaries of the Sagittarius constellation and its surroundings
Location of β1 Sagittarii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagittarius
Right ascension 19h 22m 38.29770s[1]
Declination −44° 27′ 32.2458″[1]
Apparent magnitude (V) +4.01[2]
Characteristics
Spectral type B9 V + A5 V[3][4]
U−B color index −0.39[2]
B−V color index −0.10[2]
Astrometry
Radial velocity (Rv)−10.7±2.7[5] km/s
Proper motion (μ) RA: +13.67[1] mas/yr
Dec.: −19.03[1] mas/yr
Parallax (π)10.40 ± 1.14 mas[1]
Distanceapprox. 310 ly
(approx. 100 pc)
Absolute magnitude (MV)−1.32[6]
Details
β1 Sgr A
Mass3.67±0.14[7] M☉
Radius2.73[4] R☉
Luminosity324[7] L☉
Surface gravity (log g)3.83[8] cgs
Temperature11,960[8] K
Metallicity [Fe/H]−0.35[8] dex
Rotational velocity (v sin i)85±13[4] km/s
Age224[9] Myr
β1 Sgr B
Radius1.89[4] R☉
Rotational velocity (v sin i)140±21[4] km/s
Other designations
Arkab Prior, β1 Sgr, CD−44° 13277, FK5 1502, HD 181454, HIP 95241, HR 7337, SAO 229646, WDS J19226-4428A[10]
Database references
SIMBADdata

Beta1 Sagittarii, Latinized from β1 Sagittarii, is a binary star system in the zodiac constellation of Sagittarius,[11] next to the southern constellation border with Telescopium. The brighter primary is named Arkab Prior /ˈɑːrkæb ˈpraɪər/, the traditional name of the system.[12][13] It is visible to the naked eye with a combined apparent visual magnitude of +4.01.[2] Based upon an annual parallax shift of 10.40 mas as seen from Earth,[1] it is located roughly 310 light-years from the Sun. At Beta1 Sagittarii's distance, the visual magnitude is diminished by an extinction factor of 0.17 due to interstellar dust.[9]

The pair of stars that constitute this system have an angular separation of 28.3[11] arc seconds, with an estimated physical separation of about 3,290 AU.[4] The primary, Beta1 Sagittarii A, is a B-type main sequence star with a stellar classification of B9 V.[3][4] It is about 95% of the way through its lifespan on the main sequence.[7] The star has around 3.7[7] times the mass of the Sun and 2.7[4] times the Sun's radius. It is an estimated 224[9] million years old and is spinning with a projected rotational velocity of 85 km/s.[4] The star is radiating 324[7] times the luminosity of the Sun from its photosphere at an effective temperature of 11,960 K.[8]

The companion, Beta1 Sagittarii B, is a magnitude 7.4[11] A-type main sequence star with a class of A5 V.[3] It has 1.89[4] times the radius of the Sun and may be spinning faster than the primary with a projected rotational velocity of 140 km/s.[4]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Nicolet1978 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference levato1975 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i j k Cite error: The named reference Howe2009 was invoked but never defined (see the help page).
  5. ^ 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 c d e Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Hempel2003 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kunitzsch was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference IAU-LSN was invoked but never defined (see the help page).