HP Bootes (HP Boötis , abbreviated HP Boo ) is a variable star in the northern constellation Bootes . The star has a visible magnitude of 5.99 m [2] , and, according to the Bortl scale , is visible to the naked eye even in the suburban sky ( Eng. Suburban sky ).
| HP Bootes | |||
|---|---|---|---|
| Multiple star | |||
   | |||
| Observational data ( Age J2000.0 ) | |||
| Type of | Multiple star | ||
| Right ascension | |||
| Declination | |||
| Distance | 59.3 ± 0.4 St. years (18.2 ± 0.1 pc ) [a] | ||
| Visible magnitude ( V ) | 5.9949 [2] | ||
| Constellation | Bootes | ||
| Astrometry | |||
| Radial velocity ( R v ) | −1.5 [3] km / s | ||
| Own movement (μ) | RA: 143.91 [2] Dec: 32.69 [2] | ||
| Parallax (π) | 55.03 ± 0.34 [2] mas | ||
| Absolute magnitude (V) | |||
| Characteristics | |||
| Spectral class | and | ||
| Color Index ( B - V ) | + 0.576 [2] | ||
| Color Index ( U - B ) | +0.01 [5] | ||
| Variability | BY Dra [6] | ||
| physical characteristics | |||
| Age | 4.7 [7] or 0.5 [8] billion years | ||
| Temperature | |||
| Metallicity | |||
| |||
| Database Information | |||
| SIMBAD | |||
| The star has 3 components Their parameters are presented below: | |||
From parallax measurements obtained during the Hipparcos mission, it is known that the star is removed at about 59.3 St. years ( 18.2 pc ) from the Sun [2] . The star is observed north of 67 ° S, that is, it is visible almost throughout the inhabited Earth , with the exception of Antarctica . The best time to watch is May [18] .
Currently, the star is resolved by three methods into three components. The names of these components use the HP Bootes designation “A” and the pair “BC”, according to the convention used by the Washington Catalog of Visual-Double Stars (WDS) and adopted by the International Astronomical Union (MAC) to designate star systems [19] .
Content
- 1 Properties of a multiple system
- 1.1 Component A
- 1.2 Pair BC
- 2 History of the study of the multiplicity of a star
- 3 Nearest star surroundings
- 4 notes
- 4.1 Comments
- 4.2 Sources
- 5 Links
Multiple System Properties
HP Bootes HP itself, in a first approximation, is visible as a star of the spectral class G1V [9] . However, in fact, it consists of component A and a pair of BC, brown dwarfs rotating around it. The pair was discovered in 2002 using adaptive optics at the 8-meter Gemini North telescope at the Gemini Observatory in Hawaii [20] . The couple has a 10-year period of revolution around each other, and their total mass is 10.9% of the mass of the Sun [8] .
HP Bootes is a variable star (number 90216 in the General catalog of variable stars ( GAI ) [6] ). Its apparent magnitude ranges from a few hundredths of magnitude from 5.98 m to 6.01 m . The period of brightness variation is 7.85 days , which is approximately equal to the period of rotation of the star. The type of the variable is a variable of type BY Dragon .
The age of the Bootes HP system is highly controversial: on the one hand, some studies give the star an almost sunny age of 4.7 billion years [7] . However, a separate study in 2009 gives the star a much younger age of 0.5 ± 0.3 billion years [8] .
Component A
The star’s spectrum has been a subject of debate for a long time: the star was assigned the F9IV-V spectrum [5] , that is, it was believed that the star occupies an intermediate position between dwarfs and subgiants . Then the spectral class G0-2V was assigned to the star, that is, a dwarf having the properties of stars G0, G1, G2 [18] . However, it is currently believed that component A is of spectral type G1V [9] and this means that HP Bootes A has a slightly lower mass than the mass of the Sun equal to 0.97 [9] , a smaller radius than the radius of the Sun , which is 0.94 [10] and it shines dimmer than the Sun ( 0.88 [b] ). It also indicates that the star uses hydrogen in its core as a nuclear "fuel", i.e. located on the main sequence .
A star radiates energy from its external atmosphere at an effective temperature of about 5780 K [9] , which gives it a yellow tint of a G-type star . In order for a planet like our Earth to receive about as much heat from component A as it receives from the Sun , it must be placed at a distance of 0.94 AU. , i.e. a little less than where the earth is now. Moreover, the angular dimensions of component A from this distance would look 6% larger than our Sun , as we see it from the Earth - 0.53 °, compared with the angular diameter of our Sun - 0.5 °. The star has a surface gravity of 4.18 GHS [9] or 151 4 m / s 2 , which is almost two times less than on the Sun ( 274.0 m / s 2 ). Rotating at an equatorial speed of 6.0 km / s [5] (that is, at a speed of almost 3 times that of the sun), this star needs about 9 days to complete a full revolution.
The metallicity value of HP Bootes A’s HP is also ambiguous: one study indicated that the star has a much lower metallicity : the iron content in it relative to hydrogen is 63% of the solar [9] , another source indicates that its metallicity is exactly the same as at our Sun [8] .
BC Couple
Both stars are brown dwarfs of the spectral class L4 [11] . Each brown dwarf has a mass of about 5% [8] of the solar mass and radii of about 10% [8] of the solar , as well as luminosity, which is about 0.01% [b] of the solar . Stars radiate energy from their external atmosphere at an effective temperature of about 2000 K [8] , which gives them a brownish tint to L-type stars and makes them sources of infrared [c] radiation.
The history of studying the multiplicity of a star
Triples HP's triad was discovered in 2001 and the star entered catalogs as POT 1 [d] . According to the Washington catalog of visual binary stars , the parameters of these components are given in the table [19] :
| Component | Year | Number of measurements | Position angle | Angular distance | Visible magnitude of 1 component | Visible magnitude 2 component |
| Ab | 2001 | 16 | 105 ° | 2.6 " | 5.88 m | 13.9 m |
| 2009 | 102 ° | 2.6 " | ||||
| BC | 2001 | 22 | 317 ° | 0.1 " | 13.9 m | 14.2 m |
| 2010 | 317 ° | 0.1 " |
Summarizing all the information about the star, we can say that the HP Bootes A star has satellites - a pair of stars of the 13th and 14th magnitude (component BC), lying at an angular distance of 2.6 seconds of the arc .
Nearest star environment
The following stellar systems are within 20 light-years [21] of the HP Bootes system (included only: the closest star, the brightest (<6.5 m ), and notable stars). Their spectral classes are shown against the background of the colors of these classes (these colors are taken from the names of the spectral types and do not correspond to the observed colors of stars):
| Star | Spectral class | Distance, st. years |
| McCook & Sion White Dwarf 1424 + 240 | Dc8 wd | 6.27 |
| 45 Bootes | F5 v | 7.21 |
| This Northern Crown | G2 v | 10.33 |
| Sigma Bootes | F2 v | 10.33 |
| HD 128311 | K0 v | 14.95 |
| Tau Bootes | F7 v | 07.17 |
| Ro Northern Crown | G0 v | 18.24 |
| 39 Snakes | G1 V | 18.46 |
Near the star, at a distance of 20 light years , there are about 20 red , orange dwarfs and yellow dwarfs of spectral class G, K and M, which are not on the list.
Notes
Comments
- ↑ Distance calculated by the given parallax value
- ↑ 1 2 3 4 5 Luminosity is calculated from: where R is the radius of the star, T is the temperature of its photosphere , σ is the Stefan - Boltzmann constant
- ↑ From the Wien displacement law , the radiation energy of a completely black body is maximum at a given temperature at a wavelength of λ b = (2,898⋅10 6 nm • K) / (2000 K) ≈ 1450 nm , which lies in the near infrared part of the electromagnetic spectrum
- ↑ POT - link to the catalog of openers, 1 - number of the entry in its directory
Sources
- ↑ 1 2 Perryman, MAC et al. The HIPPARCOS Catalog (Eng.) // Astronomy and Astrophysics : journal. - 1997 .-- April ( vol. 323 ). - P. L49 — L52 . - .
- ↑ 1 2 3 4 5 6 7 van Leeuwen, F. Validation of the new Hipparcos reduction // Astronomy and Astrophysics : journal. - 2007 .-- November ( vol. 474 , no. 2 ). - P. 653-664 . - DOI : 10.1051 / 0004-6361: 20078357 . - . - arXiv : 0708.1752 .
- ↑ Evans, DS (June 20–24, 1966). "The Revision of the General Catalog of Radial Velocities." Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 , University of Toronto : International Astronomical Union .
- ↑ 1 2 3 4 Collaboration G. Gaia DR2 - 2018 .-- Vol. 1345.
- ↑ 1 2 3 4 5 (English) HD 130948 - Variable of BY Dra type , Center de Données astronomiques de Strasbourg , < http://SIMBAD.u-strasbg.fr/SIMBAD/sim-id?Ident=HD+ 130948 > . Retrieved August 27, 2019.
- ↑ 1 2 HP Boo . GAISH .
- ↑ 1 2 Holmberg, J .; Nordstrom, B .; Andersen, J. The Geneva-Copenhagen survey of the solar neighborhood. III. Improved distances, ages, and kinematics (Eng.) // Astronomy and Astrophysics : journal. - 2009 .-- July ( vol. 501 , no. 3 ). - P. 941-947 . - DOI : 10.1051 / 0004-6361 / 200811191 . - . - arXiv : 0811.3982 .
- ↑ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Dupuy, Trent J .; Liu, Michael C .; Ireland, Michael J. Dynamical Mass of the Substellar Benchmark Binary HD 130948BC (Eng.) // The Astrophysical Journal : journal. - IOP Publishing 2009 .-- February ( vol. 692 , no. 1 ). - P. 729-752 . - DOI : 10.1088 / 0004-637X / 692/1/729 . - . - arXiv : 0807.2450 .
- ↑ 1 2 3 4 5 6 7 8 9 10 Chen, YQ; Nissen, PE; Zhao, G .; Zhang, HW; Benoni, T. Chemical composition of 90 F and G disk dwarfs (en supplement) // Astronomy and Astrophysics . - 2000. - February ( t. 141 ). - S. 491-506 . - DOI : 10.1051 / aas: 2000124 . - . - arXiv : astro-ph / 9912342 .
- ↑ 1 2 CADARS catalog entry: recno = 6506 Catalog of Stellar Diameters (CADARS) .
- ↑ 1 2 3 4 5 (English) NAME HD 130948BC - Brown Dwarf (M <0.08solMass) , Center de Données astronomiques de Strasbourg , < http://SIMBAD.u-strasbg.fr/SIMBAD/sim-id? Ident =% 402301997 & Name = NAME% 20HD% 20130948BC & submit = submit > . Retrieved August 27, 2019.
- ↑ C. Soubiran Vertical distribution of Galactic disk stars // Astron. Astrophys. - EDP Sciences , 2008. - Vol. 480, Iss. 1. - P. 91–101. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361: 20078788 - arXiv: 0712.1370
- ↑ SIMBAD Astronomical Database
- ↑ Gray R. O., Napier M. G., Winkler L. I. The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars // Astron. J. / J. G. III - IOP Publishing , 2001. - Vol. 121, Iss. 4. - P. 2148–2158. - ISSN 0004-6256 ; 1538-3881 - doi: 10.1086 / 319956
- ↑ Aguilera-Gómez C., Ramírez I., Chanamé J. Lithium abundance patterns of late-F stars: an in-depth analysis of the lithium desert // Astron. Astrophys. - EDP Sciences , 2018 .-- Vol. 614. - P. 55–55. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361 / 201732209
- ↑ Brewer J. M. , Fischer D. A. , Valenti J. A. Spectral properties of cool stars: extended abundance analysis of 1.617 planet-search stars // The Astrophysical Journal : Supplement Series - 2016 .-- T. 225, no. 2. - P. 32. - ISSN 0067-0049 ; 1538-4365 - doi: 10.3847 / 0067-0049 / 225/2/32
- ↑ Bonner Durchmusterung + 24 ° 2786 . Internet Stellar Database .
- ↑ 1 2 HR 5534 . A catalog of bright stars .
- ↑ 1 2 Vizier catalog entry . VizieR .
- ↑ Potter, D .; Martín, EL; Cushing, MC; Baudoz, P .; Brandner, W .; Guyon, O .; Neuhäuser, R. Hokupa'a-Gemini Discovery of Two Ultracool Companions to the Young Star HD 130948 // The Astrophysical Journal : journal. - IOP Publishing 2002. March ( vol. 567 , no. 2 ). - P. L133 — L136 . - DOI : 10.1086 / 339999 . - . - arXiv : astro-ph / 0201431 .
- ↑ Stars within 20 light-years of Bonner Durchmusterung + 24 ° 2786: (English) . Internet Stellar Database .