Iota Capricorni
{{short description|Star in the constellation Capricornus}}
{{Starbox begin
| name = Iota Capricorni
}}
{{Starbox image
| image=
{{Location mark
|image=Capricornus constellation map.svg|alt=|float=center|width=280
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=ι Cap
|x=332|y=468
}}
|caption=Location of ι Capricorni (circled)
}}
{{Starbox observe
| epoch = J2000.0
| constell = Capricornus
| dec = {{DEC|-16|50|04.3580}}
}}
{{Starbox character
| r-i =
| variable = BY Dra
}}
{{Starbox astrometry
| radial_v = {{Val|+12.31|0.13}}
| prop_mo_ra = {{val|29.403|0.189}}
| prop_mo_dec = {{val|4.909|0.123}}
| parallax = 16.2048
| p_error = 0.1688
}}
{{Starbox detail
| mass = {{Val|2.89|0.08}}
| radius = {{Val|10.67|0.62}}
| luminosity = 83
| temperature = {{Val|5200|28|fmt=commas}}
| gravity = {{Val|3.05|0.10}}
| metal_fe = {{Val|0.05|0.05}}
| rotational_velocity = {{Val|4.37|0.45}}
| age_myr = 390
}}
{{Starbox catalog
| names = ι Cap, 32 Cap, BD−17°6245, FK5 1561, HD 203387, HIP 105515, HR 8167, SAO 164346
}}
{{Starbox reference
| Simbad = iot+Cap
}}
{{Starbox end}}
Iota Capricorni (ι Cap, ι Capricorni) is a solitary, yellow-hued star in the southern constellation of Capricornus. It can be seen with the naked eye, having an apparent visual magnitude of +4.3. Based upon an annual parallax shift of 16.2 mas as seen from the Earth, the star is located about 201 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.08 due to interstellar dust.
File:IotaCapLightCurve.png light curve for iota Capricorni, adapted from Henry et al. (1995)]]
This is an evolved G-type giant star with a stellar classification of G8 III. It is classified as a BY Draconis type variable star. This is a chromospherically-active star with a longitudinal magnetic field strength of {{Val|8.3|0.6|ul=G}} and an X-ray luminosity of {{Val|4.482e30|u=erg s−1}}. The activity and photometric variation of the star allow an estimate of its rotation period as 68 days.
Iota Capricorni has an estimated 2.9 times the mass of the Sun and nearly 11 times the Solar radius. It is 390 million years old and is radiating 83 times the solar luminosity from its chromosphere at an effective temperature of 5,200 K.
Observation
On 31 January 2034, it will be occulted by Venus over a small part of Siberia, Mongolia and China.{{cite book |date=2002 |first=Jan |last=Meeus |chapter=Mutual occultations of planets |pages=174–185 |title=More Mathematical Astronomy Morsels |isbn=0943396743 |url=https://falakmu.id/khgt/dokumen/More%20mathematical%20astronomy%20morsels%20(Jean%20Meeus)%20(Z-Library).pdf}}{{rp|166}}
Chinese name
In Chinese, {{lang|zh|十二國}} ({{lang|zh-Latn|Shíer Guó}}), meaning Twelve States, refers to an asterism which represents twelve ancient states in the Spring and Autumn period and the Warring States period, consisting of ι Capricorni, φ Capricorni, 38 Capricorni, 35 Capricorni, 36 Capricorni, χ Capricorni, θ Capricorni, 30 Capricorni, 33 Capricorni, ζ Capricorni, 19 Capricorni, 26 Capricorni, 27 Capricorni, 20 Capricorni, η Capricorni and 21 Capricorni.{{in lang|zh}} 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}. Consequently, the Chinese name for ι Capricorni itself is {{lang|zh|代一}} ({{lang|zh-Latn|Dài yī}}, {{langx|en|the First Star of Dai}}), meaning that this star (together with 37 Capricorni[http://www.ianridpath.com/startales/capricornus.htm Iad Ridpath's Startales - Capricornus the Sea Goat]) represents the state Dai (or Tae)({{lang|zh|代}}).{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060704.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 4 日] {{Webarchive|url=https://web.archive.org/web/20110522123616/http://aeea.nmns.edu.tw/2006/0607/ap060704.html |date=2011-05-22 }}
Planetary system
In 2022, two exoplanets, both super-Jovian in mass, were discovered in orbit around Iota Capricorni using a combination of radial velocity and astrometry. The inner planet has a highly eccentric orbit.
{{Orbitbox planet begin
| name = Iota Capricorni
| period_unit = year
}}
{{Orbitbox planet
| exoplanet = b
| mass = {{val|3.480|0.589|0.531|p=≥}}
| radius =
| semimajor = {{val|1.771|0.056|0.062}}
| period = {{val|1.403|0.021|0.022}}
| eccentricity = {{val|0.732|0.049}}
| inclination =
}}
{{Orbitbox planet
| exoplanet = c
| mass = {{val|7.485|3.395|2.210}}
| radius =
| semimajor = {{val|5.067|0.204|0.196}}
| period = {{val|6.793|0.260|0.226}}
| eccentricity = {{val|0.202|0.125|0.101}}
| inclination = {{val|158.462|6.927|9.058}}
}}
{{Orbitbox end}}
References
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| title=iot Cap -- Variable of BY Dra type
| work=SIMBAD Astronomical Database
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}}
{{Stars of Capricornus|state=collapsed}}
{{DEFAULTSORT:Iota Capricorni}}
Category:BY Draconis variables