Zeta Delphini

Zeta Delphini
	Location of ζ Delphini (circled)
Observation data; Epoch J2000 Equinox ICRS
Constellation	Delphinus
Right ascension	20h 35m 18.53621s
Declination	+14° 40′ 27.1739″
Apparent magnitude (V)	+4.647
Characteristics
Evolutionary stage	main sequence
Spectral type	A3Va / L5
U−B color index	+0.14
B−V color index	+0.105
Astrometry
Radial velocity (Rv)	−27.68±0.37 km/s
Proper motion (μ)	RA: 45.504 mas/yr ; Dec.: 11.510 mas/yr
Parallax (π)	14.9441±0.1284 mas
Distance	218 ± 2 ly ; (66.9 ± 0.6 pc)
Absolute bolometric; magnitude (Mbol)	0.523 / 14.59
Details
ζ Del A
Mass	2.5 ± 0.2 M☉
Luminosity	48.63 ± 1.66 L☉
Surface gravity (log g)	3.60±0.12 cgs
Temperature	8236±124 K
Metallicity [Fe/H]	−0.05 dex
Rotational velocity (v sin i)	108.0±3.6 km/s
Age	525 ± 125 Myr
ζ Del B
Mass	55 ± 10 MJup
Luminosity	0.00012 ± 0.00001 L☉
Surface gravity (log g)	5.0+0.5; −1.0 cgs
Temperature	1550+250; −100 K
Age	525 ± 125 Myr
Other designations
	ζ Del, 4 Del, BD+14°4353, HD 196180, HIP 101589, HR 7871, SAO 106274
Database references
SIMBAD	ζ Del
	ζ Del B

Zeta Delphini is a star with a brown dwarf companion in the constellation of Delphinus. Its name is a Bayer designation that is Latinized from ζ Delphini and abbreviated Zeta Del or ζ Del. With an apparent visual magnitude of about 4.6, it is faintly visible to the naked eye. Parallax measurements of the system made by the Gaia spacecraft put it at a distance of about 218 light-years (67 parsecs). It is drifting closer with a line of sight velocity component of −27.7 km/s.

Zeta Delphini has a spectral type of A3V, presenting as an A-type main-sequence star. These types of stars are bluish-white colored, and have effective temperatures between 7100 and 11500 K: Zeta Delphini has a temperature of 8336 K. Its age is estimated to be around 500 million years, considerably younger than the Sun.

In 2014, the discovery of a brown dwarf companion orbiting Zeta Delphini was announced. Zeta Delphini B is a brown dwarf with a spectral type of L5 (but may be from L3 to L7), and has a mass of about 55 Jupiters. At over 13 arcseconds away, this brown dwarf is separated at least 910 AU from Zeta Delphini.

A 2021 study identified Zeta Delphini as a Lambda Boötis star, a type of star with peculiar chemical abundances. It is the first known Lambda Boötis star orbited by a brown dwarf.

References

1 2 3 4 5 6 7 8 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
1 2 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
↑ Zorec, J.; Royer, F. (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.
1 2 3 4 5 6 7 De Rosa, R. J.; et al. (2014). "The VAST Survey - IV. A wide brown dwarf companion to the A3V star ζ Delphini". Monthly Notices of the Royal Astronomical Society. 445 (4): 3694. arXiv:1410.0005. Bibcode:2014MNRAS.445.3694D. doi:10.1093/mnras/stu2018. S2CID 34066734.
1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
1 2 3 4 Saffe, C.; Miquelarena, P.; et al. (March 2021). "Chemical analysis of early-type stars with planets". Astronomy & Astrophysics. 647: A49. arXiv:2101.04416. Bibcode:2021A&A...647A..49S. doi:10.1051/0004-6361/202040132.
↑ "zet Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 March 2017.
↑ Adelman, Saul J. (2004). "The physical properties of normal A stars". Proceedings of the International Astronomical Union. 2004: 1–11. Bibcode:2004IAUS..224....1A. doi:10.1017/S1743921304004314.

[GaiaDR3-1] 1 2 3 4 5 6 7 8 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[TYC2-2] 1 2 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.

[zorec2012-3] Zorec, J.; Royer, F. (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.

[vast-4] 1 2 3 4 5 6 7 De Rosa, R. J.; et al. (2014). "The VAST Survey - IV. A wide brown dwarf companion to the A3V star ζ Delphini". Monthly Notices of the Royal Astronomical Society. 445 (4): 3694. arXiv:1410.0005. Bibcode:2014MNRAS.445.3694D. doi:10.1093/mnras/stu2018. S2CID 34066734.

[EgUBV-5] 1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.

[Saffe2021-6] 1 2 3 4 Saffe, C.; Miquelarena, P.; et al. (March 2021). "Chemical analysis of early-type stars with planets". Astronomy & Astrophysics. 647: A49. arXiv:2101.04416. Bibcode:2021A&A...647A..49S. doi:10.1051/0004-6361/202040132.

[SIMBAD-7] "zet Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 March 2017.

[8] Adelman, Saul J. (2004). "The physical properties of normal A stars". Proceedings of the International Astronomical Union. 2004: 1–11. Bibcode:2004IAUS..224....1A. doi:10.1017/S1743921304004314.