NGC 6774 (other designations - Ruprecht 147 , OCL 65 ) is an open cluster in the constellation Sagittarius . It is located at a distance of about 962 light-years [2] from the Sun. This object is one of those listed in the original edition of the New General Catalog .
| NGC 6774 | |
|---|---|
| Star cluster | |
| Research history | |
| Discoverer | John Herschel |
| opening date | July 27, 1830 |
| Designations | NGC 6774 , Ruprecht 147 , OCL 65 |
| Observational data ( Age J2000.0 ) | |
| Type of | Type III2m open cluster |
| Right ascension | |
| Declination | |
| Distance | |
| Visible Dimensions (V) | 20,0 ' |
| Constellation | Sagittarius |
Content
Observation History
Despite its potentially interesting characteristics for science, it was practically not studied by astronomers until the 2000s. In fact, all references to it in the scientific literature come down to various catalogs. NGC 6774 was discovered by John Herschel in 1830 . He described it as “a very large disordered space filled with unrelated stars” ( Eng. “A very large straggling space full of loose stars” ) [3] . In 1863, Herschel appropriated him the name GC 4481 [4] . Since then, the cluster has received various designations: NGC 6774, OCL 65, Lund 883 and Ruprecht 147 (R 147). On some maps, it was even indicated as asterism , and not as a full cluster [5] . Working on the 2000 year catalog Tycho-2 , astronomers have identified 33 stars in the cluster with similar intrinsic motion . Then, based on two parallax measurements obtained by the Hipparcos telescope, the distance to the stars HIP 94635 (280 ± 79 pc) and HIP 94803 (267 ± 74 pc) was determined. Thus, the average distance to NGC 6774 was determined to be 250 parsecs or 815 light years [6] . Later, the distance was specified to 300 parsecs, and the age and number of cluster members were verified. In 2017, a brown dwarf was first discovered by the star EPIC 219388192 , owned by NGC 6774 [7] . In 2018, the first exoplanet known in the cluster was discovered in star K2-231 [2] .
Features
NGC 6774 belongs to the numerous open clusters of our Galaxy . It can be observed with binoculars at the end of summer in the constellation Sagittarius. This is the oldest cluster located close to the solar system [8] . His age is estimated at approximately 3 billion years [2] . It consists of about 150 stars, among which there are red giants , blue vagabonds and spectrally binary stars . In terms of aggregate characteristics, NGC 6774 is very similar to another open cluster, NGC 7762 [9] . Their main difference is their location in the Galaxy. NGC 6774 is located 300 pc from the solar system in the constellation Sagittarius, and NGC 7762 is located 900 pc in the constellation Cepheus .
Cluster stars
Notes
- ↑ Kharchenko N. V., Piskunov A. E., S. Röser et al. Astrophysical parameters of Galactic open clusters // Astron. Astrophys. - EDP Sciences , 2005. - Vol. 438, Iss. 3. - P. 1163–1173. - ISSN 0004-6361 ; 0365-0138 ; 1432-0746 ; 1286-4846 - doi: 10.1051 / 0004-6361: 20042523
- ↑ 1 2 3 Jason Lee Curtis et al. K2-231 b: A sub-Neptune exoplanet transiting a solar twin in Ruprecht 147 . Arxiv.org (Mar 20, 2018). Date of appeal April 14, 2018.
- ↑ Herschel, J. Observations of Nebulae and Clusters of Stars, Made at Slough, with a Twenty-Feet Reflector, between the Years 1825 and 1833 (Eng.) // Philosophical Transactions of the Royal Society of London (1776-1886): Journal. - 1833. - 1 January. - P. 463 . - DOI : 10.1098 / rstl . 1833.0021 .
- ↑ Herschel, J. Catalog of Nebulae and Clusters of Stars (English) // Catalog of Nebulae and Clusters of Stars. Herschel, J Philosophical Transactions of the Royal Society of London (1776-1886): Journal. - 1864. - 1 January. - P. 127 . - DOI : 10.1098 / rstl . 1864.0001 .
- ↑ Burnham, Robert. Burnham's celestial handbook; an observer's guide to the universe beyond the solar system. A descriptive catalog and reference handbook of deep-sky wonders for the observer, student, research worker, amateur or professional astronomer. (eng.) . Flagstaff, Ariz., Celestial Handbook Publications (00/1966). Date of appeal April 14, 2018.
- ↑ Perryman, MAC, & ESA. The HIPPARCOS and TYCHO catalogs. Astrometric and photometric star catalogs derived from the ESA HIPPARCOS Space Astrometry Mission . The Hipparcos and Tycho catalogs. Astrometric and photometric star catalogs derived from the ESA Hipparcos Space Astrometry Mission, Publisher: Noordwijk, Netherlands: ESA Publications Division, 1997, Series: ESA SP Series vol no: 1200, ISBN: 9290923997 (set) (00/1997). Date of appeal April 14, 2018.
- ↑ Grzegorz Nowak et al. EPIC 219388192b — An Inhabitant of the Brown Dwarf Desert in the Ruprecht 147 Open Cluster . The Astronomical Journal (03/2017). Date of appeal April 14, 2018.
- ↑ Jason L. Curtis, Angie Wolfgang, Jason T. Wright, John M. Brewer, John A. Johnson. Ruprecht 147: The oldest nearby open cluster as a new benchmark for stellar astrophysics . Arxiv.org (Jan 5, 2013). Date of appeal April 14, 2018.
- ↑ Giovanni Carraro, Eugene Semenko, Sandro Villanova. Radial velocities and metallicities of red giant stars in the old open cluster NGC 7762 . Arxiv.org (8 Nov 2016). Date of appeal April 16, 2018.
See also
- List of Messier objects
- New shared directory
Links
- Information in English and French from the original “ New General Catalog ”
- Information (Eng.) From the Revised New General Catalog
- SIMBAD
- VizieR (English)
- NASA / IPAC Extragalactic Database
- List of NGC 6774 Publications