Location of 1 Delphini (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| A | |
| Right ascension | 20 30 17.9623 |
| Declination | +10° 53′ 45.335″ |
| Apparent magnitude (V) | 6.20±0.01 |
| B | |
| Right ascension | 20 30 17.9505 |
| Declination | +10° 53′ 46.244″ |
| Apparent magnitude (V) | 8.00±0.01 |
| Characteristics | |
| Spectral type | A1:III shell |
| U−B color index | −0.11 |
| B−V color index | −0.03 |
| Astrometry | |
| Radial velocity (Rv) | −15.5 ± 2 km/s |
| Absolute magnitude (MV) | −0.69 |
| A | |
| Proper motion (μ) | RA: +19.320 mas/yr Dec.: +4.645 mas/yr |
| Parallax (π) | 4.6400 ± 0.0616 mas |
| Distance | 703 ± 9 ly (216 ± 3 pc) |
| B | |
| Proper motion (μ) | RA: +19.545 mas/yr Dec.: +4.710 mas/yr |
| Parallax (π) | 4.1851 ± 0.1421 mas |
| Distance | 780 ± 30 ly (239 ± 8 pc) |
| Details | |
| A | |
| Mass | 3.1±0.3 M☉ |
| Surface gravity (log g) | 3.66±0.77 cgs |
| Temperature | 10,651 −1156 K |
| Metallicity | 0.00 dex |
| Rotational velocity (v sin i) | 217 km/s |
| Age | 246 Myr |
| B | |
| Surface gravity (log g) | 4.14 −0.47 cgs |
| Rotational velocity (v sin i) | 370 km/s |
| Other designations | |
| 1 Delphini, BD+10°4303, HD 195325, HIP 101160, HR 7836, SAO 106172, WDS J20303+1054AB | |
| Database references | |
| SIMBAD | data |
1 Delphini (1 Del) is the Flamsteed designation for a close binary star in the equatorial constellation Delphinus. With a combined apparent magnitude of 6.08, it is barely visible to the naked eye, even under ideal conditions. Parallax measurements put the components at a distance 703 and 780 light years respectively. However, its approaching the Solar System with a radial velocity of 15 km/s.
1 Del consists of three components. The brightest of them has a magnitude of 6.1; a companion located around 0.9 arcseconds from the primary has an apparent magnitude of 8.1; and a third star, located much farther away at around 17 arcseconds from component A, is the faintest with a magnitude of around 14 and is an unrelated background object.
The entire system has a stellar classification of A1: III sh, indicating that it is a white giant + a shell star. However, there is some uncertainty about the temperature class. When resolved, the secondary has a class of B9. 1 Del A has 3 times the mass of the Sun and an effective temperature of 10,651 K, giving it a bluish white glow. It is estimated to be almost 250 million years old and has a solar metallicity. Both components spin rapidly, with projected rotational velocities of 217 and 370 km/s respectively. As for the peculiarities, the shell star is a primary component; the spectrum of the secondary shows broad absorption lines.
Due to the stability of the emission lines data from 1 Delphini has been used for developing models of shell stars and Be stars.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (March 2002). "The Tycho double star catalogue". Astronomy & Astrophysics. 384 (1): 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822. ISSN 0004-6361.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- Abt, Helmut A.; Morrell, Nidia I. (July 1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182. ISSN 0067-0049.
- ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
- Ralph Elmer Wilson (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W. LCCN 54001336.
- 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. ISSN 1063-7737. S2CID 255204555.
- ^ 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. ISSN 0004-6361.
- ^ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. ISSN 0320-0108. S2CID 255201789.
- ^ Kubát, Jiří; Kubátová, Brankica; Doležalová, Barbora; Iliev, Lubomir; Šlechta, Miroslav (2016). "Spectroscopy of close visual binary components of the stable shell star 1 Delphini". Astronomy and Astrophysics. 587: A22. arXiv:1601.05236. Bibcode:2016A&A...587A..22K. doi:10.1051/0004-6361/201526414. S2CID 118706088.
- Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
Further reading
- Merrill, Paul W.; Burwell, Cora G. (November 1949). "Second Supplement to the Mount Wilson Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines". The Astrophysical Journal. 110: 387. Bibcode:1949ApJ...110..387M. doi:10.1086/145215. eISSN 1538-4357. ISSN 0004-637X.
- Merrill, Paul W. (January 1952). "Spectra of Two Stars with Stable Shells". The Astrophysical Journal. 115: 42. Bibcode:1952ApJ...115...42M. doi:10.1086/145507. eISSN 1538-4357. ISSN 0004-637X.
- van den Bos, W. H. (February 1958). "Micrometer measures of double stars". The Astronomical Journal. 63: 63. Bibcode:1958AJ.....63...63V. doi:10.1086/107694. ISSN 0004-6256.
- Ringuelet-Kaswalder, Adela E. (August 1963). "Shell Stars and Rotationally Unstable Be Stars". Publications of the Astronomical Society of the Pacific. 75 (445): 323. Bibcode:1963PASP...75..323R. doi:10.1086/127960. eISSN 1538-3873. ISSN 0004-6280.
- Gray, David F.; Marlborough, J. M. (March 1974). "Photoelectric Profile Measurements of Halpha and Hbeta in be Stars". The Astrophysical Journal Supplement Series. 27: 121. Bibcode:1974ApJS...27..121G. doi:10.1086/190291. eISSN 1538-4365. ISSN 0067-0049.
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