Iota Delphini

Iota Delphini (ι Del, ι Delphini) is a star in the constellation Delphinus. It has an apparent magnitude of about 5.4, meaning that it is just barely visible to the naked eye. Based upon parallax measurements made by the Gaia spacecraft, this star is located at a distance of 196 light years.

Iota Delphini

Location of Iota Delphini (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Delphinus
Right ascension	20h 37m 49.1198s[1]
Declination	+11° 22′ 39.6308″[1]
Apparent magnitude (V)	5.42±0.01[2]
Characteristics
Spectral type	A1 IV[3]
U−B color index	+0.03[4]
B−V color index	+0.03[4]
Astrometry
Radial velocity (Rv)	−3.9±0.9[5] km/s
Proper motion (μ)	RA: +38.867 mas/yr[1] Dec.: −8.609 mas/yr[1]
Parallax (π)	16.6478 ± 0.0728 mas[1]
Distance	195.9 ± 0.9 ly (60.1 ± 0.3 pc)
Absolute magnitude (MV)	1.62[6]
Orbit[7]
Period (P)	11.039 days
Eccentricity (e)	0.23
Periastron epoch (T)	2422139.862
Argument of periastron (ω) (secondary)	61.8°
Semi-amplitude (K1) (primary)	26.0 km/s
Details
Mass	2.47[8] M☉
Radius	1.9[9] R☉
Luminosity	23[10] L☉
Surface gravity (log g)	4.29[6] cgs
Temperature	9,130[10] K
Metallicity [Fe/H]	−0.25[11] dex
Rotational velocity (v sin i)	28[12] km/s
Age	225[10] Myr
Other designations
ι Del, 5 Delphini, BD+10°4339, GC 28711, HD 196544, HIP 101800, HR 7883, SAO 106322[13]
Database references
SIMBAD	data

Iota Delphini's spectral type is A1IV, meaning it is an A-type subgiant.^[14] Observations of the star's spectrum reveal a periodic Doppler shift. This means that Iota Delphini is a spectroscopic binary with a period of 11 days and an eccentricity of 0.23.^[7] However, almost no information is known about the companion star.

Iota Delphini appears to be an Am star,^[6] also known as a metallic-line star. These types of stars have spectra indicating varying amounts of metals, like iron.^[15] Observations of Iota Delphini's spectrum have showed lower amounts of calcium and higher amounts of iron than usual.^[6]

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. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
3. 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.
4. Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
5. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode:1953GCRV..C......0W.
6. Stateva, I.; Iliev, I. Kh.; Budaj, J. (2012). "Abundance analysis of Am binaries and search for tidally driven abundance anomalies - III. HD 116657, HD 138213, HD 155375, HD 159560, HD 196544 and HD 204188". Monthly Notices of the Royal Astronomical Society. 420 (2): 1207–1216. arXiv:1111.0978. Bibcode:2012MNRAS.420.1207S. doi:10.1111/j.1365-2966.2011.20108.x. S2CID 118574727.
7. Pourbaix, D.; et al. (2004). "S_B⁹: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088.
8. De Rosa, R. J.; et al. (January 2014). "The VAST Survey - III. The multiplicity of A-type stars within 75 pc". Monthly Notices of the Royal Astronomical Society. 437 (2): 1216–1240. arXiv:1311.7141. Bibcode:2014MNRAS.437.1216D. doi:10.1093/mnras/stt1932. S2CID 88503488.
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. Launhardt, R.; Henning, Th.; Quirrenbach, A.; Ségransan, D.; Avenhaus, H.; Van Boekel, R.; Brems, S. S.; Cheetham, A. C.; Cugno, G.; Girard, J.; Godoy, N.; Kennedy, G. M.; Maire, A. -L.; Metchev, S.; Müller, A.; Musso Barcucci, A.; Olofsson, J.; Pepe, F.; Quanz, S. P.; Queloz, D.; Reffert, S.; Rickman, E. L.; Ruh, H. L.; Samland, M. (2020). "ISPY-NACO Imaging Survey for Planets around Young stars. Survey description and results from the first 2.5 years of observations". Astronomy and Astrophysics. 635: 635. arXiv:2002.01807. Bibcode:2020A&A...635A.162L. doi:10.1051/0004-6361/201937000. S2CID 211032080.
11. Anders, F.; Khalatyan, A.; Chiappini, C.; Queiroz, A. B.; Santiago, B. X.; Jordi, C.; Girardi, L.; Brown, A. G. A.; Matijevic, G.; Monari, G.; Cantat-Gaudin, T.; Weiler, M.; Khan, S.; Miglio, A.; Carrillo, I.; Romero-Gómez, M.; Minchev, I.; de Jong, R. S.; Antoja, T.; Ramos, P.; Steinmetz, M.; Enke, H. (1 August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy and Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. S2CID 131780028.
12. David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
13. "iot Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 15 January 2016.
14. Allen, J. S. "The Classification of Stellar Spectra". UCL Department of Physics and Astronomy: Astrophysics Group. Retrieved 1 January 2014.
15. Am star Archived 2017-08-04 at the Wayback Machine, The Internet Encyclopedia of Science, David Darling. Accessed on line August 14, 2008.