13 Delphini

13 Delphini is a binary star^[2] in the equatorial constellation Delphinus, with a combined apparent magnitude of 5.64.^[12] The system is located at a distance of 471 light years but is approaching the Solar System with a heliocentric radial velocity of about −7 km/s.^[6]

13 Delphini

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Delphinus
A
Right ascension	20h 47m 48.3330s[1]
Declination	+06° 00′ 29.551″[1]
Apparent magnitude (V)	5.66[2]
B
Right ascension	20h 47m 48.3012s[1]
Declination	+06° 00′ 28.127″[1]
Apparent magnitude (V)	8.51[2]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	A0 V[4]
U−B color index	−0.09[5]
B−V color index	−0.01[5]
Astrometry
Radial velocity (Rv)	−7±4.3[6] km/s
Absolute magnitude (MV)	−0.01[7]
A
Proper motion (μ)	RA: +8.255 mas/yr[1] Dec.: −13.162 mas/yr[1]
Parallax (π)	6.9265 ± 0.0489 mas[1]
Distance	471 ± 3 ly (144 ± 1 pc)
B
Proper motion (μ)	RA: +5.663 mas/yr[8] Dec.: −12.280 mas/yr[8]
Parallax (π)	6.6697 ± 0.0989 mas[8]
Distance	489 ± 7 ly (150 ± 2 pc)
Details
Mass	2.51+0.31 −0.36[9] M☉
Radius	3.7±0.4[9] R☉
Luminosity	119+20 −17[3] L☉
Surface gravity (log g)	3.69+0.61 −0.69[9] cgs
Temperature	9,840+91 −90[3] K
Metallicity [Fe/H]	0.00[10] dex
Rotational velocity (v sin i)	170[11] km/s
Age	307[10] Myr
Other designations
13 Del, 18 G. Delphini, AG+05°3035, BD+05°4613, GC 28986, HD 198069, HIP 102633, HR 7953, SAO 126222, WDS J20478+0600A
Database references
SIMBAD	data

13 Delphini A has an apparent magnitude of 5.66, while its companion has an apparent magnitude of 8.51.^[2] As of 2016, the pair have a separation of 1.5″ located at a position angle of 200°.^[13]

13 Delphini has a blended stellar classification of A0 V,^[4] indicating that it is an ordinary A-type main-sequence star. However, when the components are analysed individually, the primary star is given a class of B9V.^[14] It has 2.51 times the mass of the Sun^[9] and has an effective temperature of 9,840 K.^[3] However, the star is large for its class, having a radius almost 4 times that of the Sun^[9] and a luminosity 119 times greater.^[3] This is due to 13 Delphini having completed 86.1% of its main sequence lifetime^[3] and has led one source to classify it as a subgiant instead.^[15] It spins rapidly with a projected rotational velocity of 170 km/s^[11] and has an age of 307 million years.^[10]

References

1. 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.
2. Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
3. Zorec, J.; Royer, F. (January 2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. S2CID 55586789.
4. Paunzen, E.; Duffee, B.; Heiter, U.; Kuschnig, R.; Weiss, W. W. (July 2001). "A spectroscopic survey for λ Bootis stars". Astronomy & Astrophysics. 373 (2). EDP Sciences: 625–632. Bibcode:2001A&A...373..625P. doi:10.1051/0004-6361:20010630. ISSN 0004-6361.
5. Cousins, A. W. J. (1971). "Photometric standard stars". Royal Observatory Annals. 7: 86. Bibcode:1971ROAn....7.....C.
6. 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. ISSN 1063-7737. S2CID 119231169.
7. 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.
8. 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.
9. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256.
10. 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.
11. Royer, F.; Zorec, J.; Gómez, A. E. (23 November 2006). "Rotational velocities of A-type stars". Astronomy & Astrophysics. 463 (2): 671–682. arXiv:astro-ph/0610785. Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224. eISSN 1432-0746. ISSN 0004-6361.
12. Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (2002-03-01). "The Tycho double star catalogue". Astronomy and Astrophysics. 384: 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822. ISSN 0004-6361.
13. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256.
14. Palmer, D. R.; Walker, E. N.; Jones, D. H. P.; Wallis, R. E. (1968). "The radial velocities spectral types and projected rotational velocities of 633 bright northern A stars". Royal Greenwich Observatory Bulletins. 135: 385. Bibcode:1968RGOB..135..385P.
15. 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.