HD 30856#Planetary system

HD 30856 A is an evolved star in the red-giant branch, with a spectral type of K0 III, a radius of 4.4 {{Solar radius|link=y}}, and a mass of 1.17 {{Solar mass|link=y}}. The surface temperature of HD 30856 is estimated to be about 4,895 K, which gives it an orange color. The star is roughly 10 times as bright as the Sun, which, combined with a distance of 429 light-years, places its apparent magnitude at 7.91,{{R|esa97|luhn19|johnson11}} too dim to be visible from Earth by the naked eye. The star is aged approximately 3.8 billion years,{{R|johnson11}} making it younger than the Sun (4.6 billion years old).

Through the use of adaptive optics, observations at the Keck II telescope in Hawaii revealed the existence of another star, designated HD 30856 B, about 0.8 arcseconds east-southeast of HD 30856.{{R|ngo17}} HD 30856 B has a mass of 0.54 {{Solar mass}} and a temperature of 3700–4150 K,{{R|ngo17}}{{efn|name=n1}} typical for an M0V–M1V red dwarf.{{efn|name=n2}}

Since the star shares a very similar proper motion with HD 30856 A, the two stars are believed to be in a binary system. HD 30856 B revolves around the primary star (A) in a wide orbit, with a semi-major axis of 93 ± 8 AU.{{R|ngo17}}

In 2019, the People's Republic of Burkina Faso was assigned to giving the HD 30856 A system a proper name as part of the IAU100 NameExoWorlds Project,{{R|new_los}} planned to celebrate the hundredth anniversary of the International Astronomical Union (IAU), which grants the right to name an exoplanetary system to every state and territory in the world. Names were submitted and selected within Burkina Faso, which were then presented to the IAU to be officially recognized.{{R|new_method}} On 17 December 2019, the IAU announced that HD 30856 A and its planet, b, were named Mouhoun and Nakanbé, respectively.{{R|new_fr}}

Mouhoun is named after the Black Volta (locally called Mouhoun), Burkina Faso's largest river that serves a crucial societal role in the western part of the country. Nakanbé is the native name for the White Volta, the second largest river in the nation with its source located in the Sahel region.{{R|new_fr}}

In 2011, radial-velocity observations made at the W. M. Keck Observatory revealed the existence of one exoplanet around HD 30856 A.{{R|johnson11}} The planet, HD 30856 Ab, is thought to be a gas giant at least 1.5 times the mass of Jupiter, which orbits its host star at a distance of 1.85 AU once every {{convert|847|day|year|abbr=off}}.{{R|luhn19}} Its orbit is nearly circular (i.e., with a low eccentricity),{{R|luhn19}} similar to planets in the Solar System.

{{OrbitboxPlanet begin

| table_ref = {{R|luhn19}}

}}

{{OrbitboxPlanet

| exoplanet = HD 30856 Ab (Nakanbé)

| mass = >1.547

| period = 847.468 ± 19.811

| semimajor = 1.85

| eccentricity = 0.061 ± 0.058

| radius = 1.228

}}

{{Orbitbox end}}

{{Reflist |refs=

{{cite simbad |title=HD 30856 |access-date=2024-07-30}}

{{Citation |author=ESA |author-link=European Space Agency |date=1997 |title=The HIPPARCOS and TYCHO catalogues. Astrometric and photometric star catalogues derived from the ESA HIPPARCOS Space Astrometry Mission |journal=Esa Special Publication |publisher=ESA Publications Division |place=Noordwijk, Netherlands |series=ESA SP Series |volume=1200 |isbn=9290923997 |bibcode=1997ESASP1200.....E }}

{{Cite web |url=http://www.nameexoworlds.iau.org/list-of-stars |title=List of stars and planets |website=Name ExoWorlds |publisher=IAU |accessdate=2019-09-15 }}

{{Cite web |url=http://www.nameexoworlds.iau.org/methodology |title=Methodology |website=Name ExoWorlds |publisher=IAU |accessdate=2019-09-15 }}

{{cite journal | last1=Luhn | first1=Jacob K. | last2=Bastien | first2=Fabienne A. | last3=Wright | first3=Jason T. | last4=Johnson | first4=John A. | last5=Howard | first5=Andrew W. | last6=Isaacson | first6=Howard | title=Retired A Stars and Their Companions. VIII. 15 New Planetary Signals around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts | journal=The Astronomical Journal | volume=157 | issue=4 | date=2019-04-01 | issn=0004-6256 | doi=10.3847/1538-3881/aaf5d0 | doi-access=free | page=149| arxiv=1811.03043 | bibcode=2019AJ....157..149L }}

{{cite journal | last1=Johnson | first1=John Asher | last2=Clanton | first2=Christian | last3=Howard | first3=Andrew W. | last4=Bowler | first4=Brendan P. | last5=Henry | first5=Gregory W. | last6=Marcy | first6=Geoffrey W. | last7=Crepp | first7=Justin R. | last8=Endl | first8=Michael | last9=Cochran | first9=William D. | last10=MacQueen | first10=Phillip J. | last11=Wright | first11=Jason T. | last12=Isaacson | first12=Howard | title=Retired a Stars and Their Companions. Vii. 18 New Jovian Planets | journal=The Astrophysical Journal Supplement Series | volume=197 | issue=2 | date=2011-12-01 | issn=0067-0049 | doi=10.1088/0067-0049/197/2/26 | page=26| arxiv=1108.4205 | bibcode=2011ApJS..197...26J }}

{{cite journal | last1=Ngo | first1=Henry | last2=Knutson | first2=Heather A. | last3=Bryan | first3=Marta L. | last4=Blunt | first4=Sarah | last5=Nielsen | first5=Eric L. | last6=Batygin | first6=Konstantin | last7=Bowler | first7=Brendan P. | last8=Crepp | first8=Justin R. | last9=Hinkley | first9=Sasha | last10=Howard | first10=Andrew W. | last11=Mawet | first11=Dimitri | title=No Difference in Orbital Parameters of RV-detected Giant Planets between 0.1 and 5 au in Single versus Multi-stellar Systems | journal=The Astronomical Journal | volume=153 | issue=6 | date=2017-06-01 | issn=0004-6256 | doi=10.3847/1538-3881/aa6cac | doi-access=free | page=242| arxiv=1704.02326 | bibcode=2017AJ....153..242N }}

{{Cite web |url=https://nameexoworlds.iau.org/_files/ugd/6358ac_5eebee4eba4f41b7a9f6201123673a24.pdf |title=Approved names |website=NameExoWorlds |publisher=IAU |accessdate=2024-07-30|page=4 }}

{{cite journal |last1=Pecaut |first1=Mark J. |last2=Mamajek |first2=Eric E. |title=Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-main-sequence Stars |journal=The Astrophysical Journal Supplement Series |date=1 September 2013 |volume=208 |issue=1 |pages=9 |doi=10.1088/0067-0049/208/1/9 |url=https://ui.adsabs.harvard.edu/abs/2013ApJS..208....9P/abstract |issn=0067-0049|arxiv=1307.2657 |bibcode=2013ApJS..208....9P |s2cid=119308564 }}

{{cite web |last1=Mamajek |first1=Eric |title=A Modern Mean Dwarf Stellar Color and Effective Temperature Sequence |url=http://www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt |publisher=University of Rochester, Department of Physics and Astronomy |access-date=5 July 2021 |date=2 March 2021}}

{{cite journal |first1=C. |last1=Cifuentes|first2=J.A. |last2=Caballero|first3=M. |last3=Cortés-Contreras|first4=D.|last4=Montes|first5=F.J.|last5=Abellán|first6=R.|last6=Dorda|first7=G.|last7=Holgado|year=2020|title=CARMENES input catalogue of M dwarfs. V. Luminosities, colours, and spectral energy distributions|journal=Astronomy and Astrophysics |volume=642 |pages=32|issue=October 2020|doi=10.1051/0004-6361/202038295 |bibcode=2020A&A...642A.115C |arxiv=2007.15077}}

{{cite journal | pmc = 4291657 | pmid=25512527 | doi=10.1073/pnas.1406545111 | volume=112 | issue=1 | title=Exoplanet orbital eccentricity: multiplicity relation and the Solar System | journal=Proc Natl Acad Sci U S A | pages=20–4 | last1 = Limbach | first1 = MA | last2 = Turner | first2 = EL|arxiv = 1404.2552 |bibcode = 2015PNAS..112...20L | year=2015 | doi-access=free }}

{{cite web|date = February 2001|title = The Bortle Dark-Sky Scale|publisher = Sky & Telescope|author = John E. Bortle|url = http://www.skyandtelescope.com/resources/darksky/3304011.html|access-date = 2009-11-18|archive-url = https://web.archive.org/web/20090323232806/http://www.skyandtelescope.com/resources/darksky/3304011.html|archive-date = 2009-03-23|url-status = dead}}

{{Cite journal |last1=Connelly |first1=J. N. |last2=Bizzarro |first2=M. |last3=Krot |first3=A. N. |last4=Nordlund |first4=Å. |last5=Wielandt |first5=D. |last6=Ivanova |first6=M. A. |date=2 November 2012 |title=The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk |journal=Science |volume=338 |issue=6107 |pages=651–655 |bibcode=2012Sci...338..651C |doi=10.1126/science.1226919 |pmid=23118187 |s2cid=21965292}}{{Registration required}}

}}

{{noteslist|notes=

{{efn|name=n1|The source publication provides three separate estimates, namely 3940 ± 200 K, 3945 ± 70 K, and 3731 ± 29 K.}}

{{efn|name=n2|According to the listed sources, typical M0V and M1V stars have masses of 0.57 / 0.54 {{Solar mass}} and surface temperatures of 3850 / 3660 K, respectively.}}

}}

• List of proper names of stars
• List of proper names of exoplanets
• List of stars in Eridanus
• List of exoplanets discovered in 2011

• {{cite encyclopedia|author=Jean Schneider|url=http://exoplanet.eu/catalog/hd_30856_b/|title=Planet HD 30856 b|encyclopedia=The Extrasolar Planet Encyclopaedia|access-date=2024-07-30}}
• {{Cite Exoplanet Archive|HD 30856|access-date=2024-07-30}}
• {{WikiSky|HD 30856}}
• {{cite web|url=http://www.nameexoworlds.iau.org/burkina-faso|title=Burkina Faso | IAU100 Name ExoWorlds|publisher=IAU|access-date=2024-07-30}}

{{Stars of Eridanus}}

{{2011 in space}}

{{DEFAULTSORT:HD 30856}}

Mouhoun

Category:Eridanus (constellation)

030856

022491

Category:Durchmusterung objects

Category:K-type giants

Category:Planetary systems with one confirmed planet

J04501787-2422077

Category:Planetary systems