37 Aquilae

37 Aquilae, abbreviated 37 Aql, is a star in the equatorial constellation of Aquila. 37 Aquilae is its Flamsteed designation. It has an apparent visual magnitude of approximately 5.12,[2] which is bright enough to be visible to the naked eye. The distance to 37 Aql can be estimated from its annual parallax shift of 7.4 mas,[1] yielding a range of 444 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −30 km/s,[1] and is predicted to come to within 72 light-years in around 4.4 million years.[2]

This article is about k Aquilae. It is not to be confused with κ Aquilae.
37 Aquilae
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension  19h 35m 07.25793s[1]
Declination −10° 33′ 37.6010″[1]
Apparent magnitude (V) 5.12[2]
Characteristics
Spectral type G8 IIIa[3]
B−V color index 1.122[4]
Astrometry
Radial velocity (Rv)−30.17±0.13[1] km/s
Proper motion (μ) RA: +7.656[1] mas/yr
Dec.: –2.316[1] mas/yr
Parallax (π)7.3533 ± 0.1453[1] mas
Distance444 ± 9 ly
(136 ± 3 pc)
Absolute magnitude (MV)−0.61[2]
Details[5]
Mass2.30±0.43 M☉
Radius23.38±1.17 R☉
Luminosity218.6±21.2 L☉
Surface gravity (log g)2.07±0.09 cgs
Temperature4,594±30 K
Metallicity [Fe/H]−0.16±0.10 dex
Rotational velocity (v sin i)8.88[4] km/s
Age1.20±0.82 Gyr
Other designations
37 Aql, BD−10° 5122, FK5 3562, GC 27046, HD 184492, HIP 96327, HR 7430, SAO 162792, PPM 236209[6]
Database references
SIMBADdata

This is an aging giant star with a stellar classification of G8 IIIa.[3] It is uncertain whether this star is on the red giant branch or the horizontal branch; Reffert et al. (2015) give 57% odd that it is the latter. In that case, their model shows an estimated age of 1.2 billion years with 2.3 times the mass of the Sun and 23 times the Sun's radius. It is radiating 219 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,594 K.[5] These coordinates are a source of X-ray emission, which is most likely coming from the star.[7]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
  2. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  3. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics, 475 (3): 1003, arXiv:0709.1145, Bibcode:2007A&A...475.1003H, doi:10.1051/0004-6361:20078233.
  5. Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy & Astrophysics, 574: A116, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360. Data is for the Horizontal Branch model.
  6. "37 Aql". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 31, 2018.
  7. Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138.
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