HD 194783

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HD 194783
Microscopium constellation map.svg
Red circle.svg
Location of HD 194783 on the map (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 20h 28m 46.74360s [1]
Declination −35° 35′ 45.1068″ [1]
Apparent magnitude  (V)6.08±0.01 [2]
Characteristics
Spectral type B8 II/III [3] or B9pHgMn [4]
B−V color index −0.11 [5]
Astrometry
Radial velocity (Rv)−9.7±1.2 [6]  km/s
Proper motion (μ)RA: +2.959  mas/yr [1]
Dec.: −21.638  mas/yr [1]
Parallax (π)4.3936 ± 0.0714  mas [1]
Distance 740 ± 10  ly
(228 ± 4  pc)
Absolute magnitude  (MV)−0.59 [7] or −1.10 [8]
Details
Mass 4.03±0.05 [1]   M☉
Radius 4.19±0.21 [9]   R☉
Luminosity 390±12 [1]   L☉
Surface gravity (log g)3.75 [10]   cgs
Temperature 14,028 [8]   K
Metallicity [Fe/H]−0.20 [10]   dex
Rotation 6  d [11]
Rotational velocity (v sin i)≤30 [11]  km/s
Age 70 [8]   Myr
Other designations
2 G. Microscopii [12] , CD−36°14166, CPD−36°9170, FK5  3637, GC  28464, HD  194783, HIP  101017, HR  7817, SAO  212160, TIC  34864575 [13]
Database references
SIMBAD data

HD 194783 (HR 7817; 2 G. Microscopii) is a solitary star located in the southern constellation Microscopium near the border with Sagittarius. It is barely visible to the naked eye as a bluish-white-hued point of light with an apparent magnitude of 6.08. [2] The object is located relatively far at a distance of 740 light-years based on Gaia DR3 parallax measurements, [1] but it is drifting closer with a heliocentric radial velocity of −9.7  km/s . [6] At its current distance, HD 194783's brightness is diminished by an interstellar extinction of 0.31 magnitudes [14] and it has an absolute magnitude of either −0.59 or −1.10, [7] [8] depending on the source.

HD 194783 has a stellar classification of B8 II/III, [3] indicating that it is an evolved B-type star with the blended luminosity class of a bright giant and a lower luminosity giant star. It has also been given a class of B9pHgMn, [4] indicating that it is a chemically peculiar mercury-manganese star. It has 4.03 times the mass of the Sun [1] and a slightly enlarged radius 4.19 times that of the Sun's. [9] It radiates 390 times the luminosity of the Sun [1] from its photosphere at an effective temperature of 14,028  K . [8] The heavy metal (iron) to hydrogen ratio–what astronomers dub as the star's metallicity–is 63% that of the Sun's. [10] HD 194783 is estimated to be approximately 70 million years old. [8]

In 1989, HD 194783 was reported to be a spectrum variable with a period of 6 days. The projected rotational velocity of the star is not known, but it is said to be no higher than 30  km/s . [11] HD 194783 was also observed to have a relatively weak magnetic field of about −43 gauss. [15]

Related Research Articles

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<span class="mw-page-title-main">HD 198716</span> Star in the constellation of Microscopium

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<span class="mw-page-title-main">HD 36187</span> Star in the constellation of Columba

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<span class="mw-page-title-main">HD 118285</span> SPB star in the constellation Chamaeleon.

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<span class="mw-page-title-main">HD 168592</span> Star in the constellation of Corona Australis

HD 168592, also designated as HR 6862 or rarely 7 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.07. Gaia DR3 parallax measurements place it at a distance of 490 light years and is currently receding with a heliocentric radial velocity of 18 km/s. At its current distance, HD 168592's brightness is diminished by 0.38 magnitudes due to interstellar dust. It has an absolute magnitude of −0.76.

<span class="mw-page-title-main">HD 31134</span> Star in the constellation of Camelopardalis

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<span class="mw-page-title-main">HD 101917</span> High proper motion star

HD 101917, also designated as HR 4509, or rarely 34 G. Chamaeleontis, is a solitary star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 6.38, placing it near the limit for naked eye visibility. The object is located relatively close at a distance of 185 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 33 km/s. At its current distance, HD 101917's brightness is diminished by 0.28 magnitudes due to interstellar dust. It has an absolute magnitude of +2.69.

<span class="mw-page-title-main">HD 189080</span> Star in the constellation of Telescopium

HD 189080, also known as HR 7621 or rarely 74 G. Telescopii, is a solitary orange-hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.18, placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements place it at a distance of 357 light years and it is currently receding rapidly with a heliocentric radial velocity of 66.9 km/s. At its current distance, HD 189080's brightness is diminished by 0.17 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of +1.1.

<span class="mw-page-title-main">HD 187420/187421</span> Binary star in the constellation Telescopium

HD 187420 and HD 187421, are the components of a binary star located in the southern constellation Telescopium. Gaia DR3 parallax measurements place the stars at a distance of 407 and 414 light years respectively. The two are separated by 23″, and they are approaching the Solar System with heliocentric radial velocities of −17.9 km/s and −21.5 km/s respectively.

<span class="mw-page-title-main">HD 169853</span> Am star; Corona Australis

HD 169853, also known as HR 6910 or rarely 9 G. Coronae Australis, is a solitary star located in the southern constellation Corona Australis. It is faintly visible to the naked eye as a white-hued point of light with an apparent magnitude of 5.62. Gaia DR3 parallax measurements imply a distance of 391 light years, and it is currently approaching the Solar System with a heliocentric radial velocity of −21.3 km/s. At its current distance, HD 169853's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust and it has an absolute magnitude of +0.13.

<span class="mw-page-title-main">HD 176425</span> A-type dwarf; Corona Australis

HD 176425, also known as HR 7177 or rarely 38 G. Coronae Australis, is a solitary, bluish-white hued star located in the southern constellation Corona Australis. It has an apparent magnitude of 6.21, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 358 light-years, and it is currently drifting closer with a heliocentric radial velocity of −12.8 km/s. At its current distance, HD 176425's brightness is diminished by an interstellar extinction factor of 0.27 magnitudes and it has an absolute magnitude of +0.75.

<span class="mw-page-title-main">HD 28780</span> A-type star in the constellation Camelopardalis

HD 28780, also known as HR 1440, is a solitary white-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.91, making it faintly viisble to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 488 light-years, and it is currently drifting closer with a heliocentric radial velocity of −22.6 km/s. At its current distance, HD 28780's brightness is diminished by 0.33 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.26.

HD 181295 is a star located in the southern constellation Telescopium. It has an apparent magnitude of 6.42, placing it near the limit of naked eye visibility, even under ideal conditions. The object is located relatively close at a distance of approximately 252 light-years based on Gaia DR3 parallax measurements, and it is currently drifting closer with a heliocentric radial velocity of −35.7 km/s. At its current distance, HD 181295's brightness is diminished by 0.22 magnitudes due to interstellar extinction and it has an absolute magnitude +2.14.

<span class="mw-page-title-main">HD 169904</span> B-type main-sequence star; Octans

HD 169904 is a solitary star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.26, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 482 light-years and it is currently drifting closer with a somewhat constrained radial velocity of −6.0 km/s. At its current distance, HD 169904's brightness is diminished by 0.24 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.19.

References

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  2. 1 2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN   0004-6361. S2CID   17128864.
  3. 1 2 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Declinations −40° to −26°. Vol. 3. Bibcode:1982mcts.book.....H.
  4. 1 2 Andersen, J.; Nordstrom, B. (September 1977). "Bright southern stars of astrophysical interest". Astronomy and Astrophysics Supplement Series. 29: 309–312. Bibcode:1977A&AS...29..309A. ISSN   0365-0138.
  5. ↑ Corben, P. M. (April 1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa. 30 (4): 37. Bibcode:1971MNSSA..30...37C. ISSN   0024-8266.
  6. 1 2 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv: 1606.08053 . Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN   1562-6873. ISSN   1063-7737. S2CID   119231169.
  7. 1 2 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN   1562-6873. ISSN   1063-7737. S2CID   119257644.
  8. 1 2 3 4 5 6 Westin, T. N. G. (April 1985). "The local system of early type stars. Spatial extent and kinematics". Astronomy and Astrophysics Supplement Series. 60: 99–134. Bibcode:1985A&AS...60...99W. ISSN   0365-0138. S2CID   119020376.
  9. 1 2 Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv: astro-ph/0404180 . Bibcode:2004A&A...426..297K. doi: 10.1051/0004-6361:20035930 . eISSN   1432-0746. ISSN   0004-6361. S2CID   6077801.
  10. 1 2 3 Anders, F.; et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics. 658: A91. arXiv: 2111.01860 . Bibcode:2022A&A...658A..91A. doi: 10.1051/0004-6361/202142369 . eISSN   1432-0746. ISSN   0004-6361.
  11. 1 2 3 Rajamohan, R.; Paranjpye, A. (1989). "The Spectrum Variable HR 7817 = HD 194783". Information Bulletin on Variable Stars. 3284: 1. Bibcode:1989IBVS.3284....1R. ISSN   0374-0676.
  12. ↑ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  13. ↑ "HD 194783". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved December 3, 2023.
  14. ↑ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv: 1709.01160 . Bibcode:2017MNRAS.472.3805G. doi: 10.1093/mnras/stx2219 . eISSN   1365-2966. ISSN   0035-8711. S2CID   118879856.
  15. ↑ Hubrig, S.; North, P.; Schöller, M.; Mathys, G. (2006). "Evolution of magnetic fields in stars across the upper main sequence: I. Catalogue of magnetic field measurements with FORS 1 at the VLT". Astronomische Nachrichten. 327 (4): 289–297. arXiv: astro-ph/0603610 . Bibcode:2006AN....327..289H. doi:10.1002/asna.200610535. ISSN   0004-6337. S2CID   16248930.
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