20 Monocerotis

{{Short description|Star in the constellation Monoceros}}

{{Starbox begin

| name = 20 Monocerotis

}}

{{Starbox image

|image=

{{Location mark

|image=Monoceros constellation map.svg|alt=|float=center|width=280

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=20 Monocerotis

|x=303|y=412

}}

|caption=Location of 20 Monocerotis (circled)

}}

{{Starbox observe

| epoch = J2000

| constell = Monoceros

| ra = {{RA|07|10|13.68177}}{{cite DR2|3059491988785706624}}

| dec = {{DEC|-04|14|13.5829}}

| appmag_v = 4.92{{cite journal |bibcode=2002yCat.2237....0D |title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system |journal=CDS/ADC Collection of Electronic Catalogues |volume=2237 |last1=Ducati |first1=J. R. |year=2002 }}

}}

{{Starbox character

| type = horizontal branch

| class = K0III{{cite journal | bibcode=1995yCat.5050....0H | title=VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991) | journal=VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H | volume=5050 | last1=Hoffleit | first1=D. | last2=Warren | first2=W. H. | year=1995 }}

| b-v = +1.03

| u-b = +0.78

}}

{{Starbox astrometry

| radial_v = +77.74{{cite journal | arxiv=1410.6422 | bibcode=2015A&A...574A..50J | doi=10.1051/0004-6361/201424474 | title=Stellar parameters and chemical abundances of 223 evolved stars with and without planets | journal=Astronomy & Astrophysics | volume=574 | pages=A50 | year=2015 | last1=Jofré | first1=E. | last2=Petrucci | first2=R. | last3=Saffe | first3=C. | last4=Saker | first4=L. | last5=Artur de la Villarmois | first5=E. | last6=Chavero | first6=C. | last7=Gómez | first7=M. | last8=Mauas | first8=P. J. D. | s2cid=53666931 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/A%2bA/574/A50/stars&Name=HD%2054810 Vizier catalog entry]

| prop_mo_ra = −0.714

| prop_mo_dec = +217.298

| parallax = 16.8419

| p_error = 0.1692

| parallax_footnote =

| absmag_v = 0.94{{cite journal | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | s2cid=119257644 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=V/137D/XHIP&HIP=34622 Vizier catalog entry]

}}

{{Starbox detail

| source = {{cite journal | title=Stellar parameters and chemical abundances of 223 evolved stars with and without planets | journal=Astronomy and Astrophysics | volume=574 | pages=A50 | display-authors=1 | last1=Jofré | first1=E. | last2=Petrucci | first2=R. | last3=Saffe | first3=C. | last4=Saker | first4=L. | last5=de la Villarmois | first5=E. Artur | last6=Chavero | first6=C. | last7=Gómez | first7=M. | last8=Mauas | first8=P. J. D. | last9=Heber | first9=U. | year=2015 | bibcode=2015A&A...574A..50J | arxiv=1410.6422 | doi=10.1051/0004-6361/201424474 | s2cid=53666931 }}

| mass = {{Val|1.07|0.20}}

| radius = {{Val|10.25|0.11}}

| temperature = {{Val|4714|46|fmt=commas}}

| luminosity = {{Val|46.36|0.56}}

| rotational_velocity = {{Val|2.33|0.50}}

| gravity = {{Val|2.53|0.10}}

| metal_fe = {{Val|−0.25|0.03}}

| age_gyr = {{Val|5.75|2.85}}

}}

{{Starbox catalog

| names = {{odlist | F=20 Mon | BD=-04°1840 | FK5=1186 | GC=9477 | HD=54810 | HIP=34622 | HR=2701 | SAO=134282 | CCDM=J07102-0414A | WDS=J07102-0414A }}{{cite simbad | title=20 Mon | access-date=2019-05-31 }}

}}

{{Starbox reference

| Simbad = 20+Mon

}}

{{Starbox end}}

20 Monocerotis is a single{{citation | title=A catalogue of multiplicity among bright stellar systems | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869 | date=2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | arxiv=0806.2878 | bibcode=2008MNRAS.389..869E | s2cid=14878976 | postscript=. }} star located about 194 light years away from the Sun in the equatorial constellation of Monoceros. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.92. The star is receding from the Earth with a heliocentric radial velocity of +78 km/s.

This object is an aging giant star with a stellar classification of K0 III. It is a red clump giant,{{citation | display-authors=1 | last1=Puzeras | first1=E. | last2=Tautvaišienė | first2=G. | last3=Cohen | first3=J. G. | last4=Gray | first4=D. F. | last5=Adelman | first5=S. J. | last6=Ilyin | first6=I. | last7=Chorniy | first7=Y. | title=High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements | journal=Monthly Notices of the Royal Astronomical Society | volume=408 | issue=2 | pages=1225–1232 | date=October 2010 | doi=10.1111/j.1365-2966.2010.17195.x | doi-access=free | bibcode=2010MNRAS.408.1225P | arxiv=1006.3857 | s2cid=44228180 }} which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. The star is around six billion years old with 1.1 times the mass of the Sun. After exhausting the supply of hydrogen at its core, it has expanded to 10.3 times the Sun's radius. It is radiating 46 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,714 K.

In addition to the primary, three visual companions have been reported: component B, with magnitude 12.93 and separation 67.8", C, with magnitude 10.16 and separation 167.9", and D, with magnitude 12.46 and separation 102.3".{{cite journal | bibcode=2001AJ....122.3466M | doi=10.1086/323920 | title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466 | year=2001 | last1=Mason | first1=Brian D. | last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I. | last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E. | doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=B/wds/wds&WDS=07102-0414 Vizier catalog entry]