Beta of the Little Horse (β Beta of the Little Horse, Beta Equulei [9] , abbreviation Beta Equ, β Equ ) is a star in the northern constellation of the Little Horse . The star has a visible magnitude of 5.15 m [3] , and, according to the Bortl scale , is visible to the naked eye at least in the illuminated suburban sky ( English Bright suburban sky ). The radial heliocentric velocity of the star is -11 km / s and this means that the star is approaching the sun [10] .
| Beta Small Horse | |||
|---|---|---|---|
| Star | |||
   | |||
| Observational data ( Epoch J2000.0 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 133 ± 4 sv. years (41 ± 1 pc ) [2] | ||
| Visible magnitude ( V ) | 5.15 [3] | ||
| Constellation | Little Horse | ||
| Astrometry | |||
| Radial velocity ( R v ) | −11.1 ± 0.8 [4] km / s | ||
| Proper motion (μ) | RA: −26.61 [1] mas per year Dec: +38.21 [1] mas per year | ||
| Parallax (π) | 24.55 ± 0.81 [1] mas | ||
| Absolute magnitude (V) | +0.13 [5] | ||
| Specifications | |||
| Spectral class | A3V [6] | ||
| Color Indicator ( B - V ) | +0.04 [3] | ||
| Color Index ( U - B ) | +0.10 [3] | ||
| physical characteristics | |||
| Radius | 4.02 [7] R ☉ | ||
| Age | 600 million [7] years | ||
| Temperature | 9,000 [7] K | ||
| Luminosity | 78.3 [5] L ☉ | ||
| Rotation | 58.0 ± 0.7 km / s [6] | ||
| |||
| Information in databases | |||
| SIMBAD | data | ||
From the parallax measurements obtained during the Hipparcos mission, it is known that the star was removed by about 133 ± 4 sv. years ( 41 ± 1 pc ) [1] . The star is observed north of 84 ° S. sh., that is, almost the entire territory of the inhabited Earth , with the exception of Antarctica . The best observation time is August [10] .
While Beta must be the second brightest star in the constellation, it is not. Alpha - the fourth star, really is the first. Number two is the Delta of the Small Horse , then the Gamma of the Small Horse follows, and only in fourth place is Beta, a star of the fifth magnitude [11] .
Star Properties
The spectral Beta class of the Small Horse is A3V [6] , which means that it is significantly larger ( 4.02 
Rotating at an equatorial speed of 58.0 km / s [6] (that is, at a speed of almost 28 times the solar speed), this star takes about 3.7 days to complete a full turn. The Beta of the Small Horse has an age of 600 million years [7] , which means that it is still very young and the planetary system, which has not yet been found in a star, is still being formed. The star detected an excess of infrared radiation , indicating the presence of a residual disk . The average temperature of the dust in the otom disk is 85 K , which indicates that the size of this disk is very large: the semi-major axis of its orbit is 104 AU. (that is, almost 2.5 times the Pluto orbit) [7] .
Optical multiplicity of a star
The multiplicity of the Beta of the Small Horse was discovered in J. Herschel until 1871 (AB, AC, AE). However, in the catalog, their discovery dates were recorded in the 1877 or 1878 years . The fact is that J. Herschel died in 1871 and his notes were published after his death. The fourth star (CD) was discovered by S. Burnham in 1877 . According to the Washington catalog of visual binary stars , the parameters of these components are listed in the table [12] :
| Component | Year | Number of measurements | Position angle | Angular distance | Visible magnitude 1 component | Visible magnitude 2 component |
| AB | 1878 | 3 | 260 ° | 31.6 " | 5.16 m | 13.6 m |
| 1912 | 257 ° | 34.4 " | ||||
| AC | 1877 | four | 309 ° | 67.4 " | 5.16 m | 11.6 m |
| 1912 | 307 ° | 69.2 " | ||||
| AE | 1878 | 3 | 276 ° | 86.3 " | 5.16 m | 12.1 m |
| 1912 | 274 ° | 89.2 " | ||||
| CD | 1877 | 2 | 10 ° | 6 " | 11.6 m | 12.6 m |
| 1901 | 8 ° | 5.8 " |
However, the star seems to have no satellites. It was once thought that she had four dim stellar companions at a distance of 34.4, 69.2, 89.2 and 5.8 seconds of arc , however, measurements of their movement show that they move very fast, and, most likely, visual satellites have no gravitational connection with The Beta of the Small Horse, that is, the stars are simply on the line of sight [13] . Moreover, a pair of CDs can really be a real double star, although little is known about it [11] .
Notes
- ↑ 1 2 3 4 5 6 (Eng.) Van Leeuwen, F. ( 2007 ), " Validation of the new Hipparcos reduction ", Astronomy and Astrophysics T. 474 (2): 653–664 , DOI 10.1051 / 0004-6361: 20078357
- ↑ Distance calculated by the given value of parallax
- ↑ 1 2 3 4 (eng.) Mermilliod, J.-C. ( 1986 ), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalog of Eggen's UBV data ( SIMBAD )
- ↑ (Eng.) Gontcharov, GA ( November 2006 ), " Pulkovo Compilation of Radial Velocities for 35.495 Hipparcos stars in a common system ", Astronomy Letters T. 32 (11): 759–771 , DOI 10.1134 / S1063773706110065
- ↑ 1 2 3 (Eng.) Anderson, E. & Francis, Ch. ( 2012 ), " XHIP: An extended hipparcos compilation ", Astronomy Letters T. 38 (5): 331 , DOI 10.1134 / S1063773712050015
- ↑ 1 2 3 4 (English) Díaz, CG; González, JF; Levato, H. & Grosso, M. ( July 2011 ), " Accurate stellar rotational velocities using the cross correlation maximum ", Astronomy & Astrophysics T. 531: A143 , DOI 10.1051 / 0004-6361 / 201016386
- ↑ 1 2 3 4 5 6 7 (English) Rhee, Joseph H .; Song, Inseok; Zuckerman, B. & McElwain, Michael ( May 2007 ), "The Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs ", The Astrophysical Journal T. 660 (2): 1556–1571 , DOI 10.1086 / 509912
- ↑ (English) * bet Equ - High proper-motion Star , Center de Données astronomiques de Strasbourg , < http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=bet+Equ > . Retrieved Jan. 27, 2019.
- ↑ (Eng.) Eggleton, PP & Tokovinin, AA ( September 2008 ), " A Catalog of Multiplications of Bright Stellar Systems ", Monthly Notice of the Royal Astronomical Society T. 389 (2): 869–879 , DOI 10.1111 / j .1365-2966.2008.13596.x
- ↑ 1 2 HR 8178 . Catalog of bright stars .
- ↑ 1 2 (English) Kaler, James B. ( December 18, 2009 ), Beta Equulei , University of Illinois , < http://stars.astro.illinois.edu/sow/betaequ.html >
- ↑ b Equulei . Alcyone Bright Star Catalog .
- ↑ (English) Mason, BD; Wycoff, GL; Hartkopf, WI & Douglass, GG ( 2014 ), " The Washington Visual Double Star Catalog ", The Astronomical Journal T. 122: 3466–3471 , DOI 10.1086 / 323920