HD 20003#Planetary system

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

{{Starbox begin}}

{{Starbox observe

| epoch = J2000.0

| constell = Hydrus

| ra = {{RA|03|07|37.91875}}

| dec = {{DEC|−72|19|18.8010}}

| appmag_v = 8.39

}}

{{Starbox character

| type =

| class = G8 V

| b-v = {{Val|0.771|0.015}}

| u-b =

| variable =

}}

{{Starbox astrometry

| radial_v = {{Val|−16.174|0.0005}}

| prop_mo_ra = +71.893

| prop_mo_dec = −7.995

| parallax = 23.8764

| p_error = 0.0283

| parallax_footnote =

| absmag_v = 5.18

}}

{{Starbox detail

| mass = {{Val|0.942|0.046}}

| radius = {{Val|0.92|0.05|0.01}}

| luminosity = {{Val|0.705|0.002|0.001}}

| temperature = 5494{{±|27}}

| gravity = {{Val|4.423|0.323}}

| metal_fe = {{Val|+0.04|0.02}}{{citation|arxiv=1705.05153|title=The HARPS search for southern extra-solar planets|year=2019 |doi=10.1051/0004-6361/201731173 |last1=Udry |first1=S. |last2=Dumusque |first2=X. |last3=Lovis |first3=C. |last4=Ségransan |first4=D. |last5=Diaz |first5=R. F. |last6=Benz |first6=W. |last7=Bouchy |first7=F. |last8=Coffinet |first8=A. |last9=Lo Curto |first9=G. |last10=Mayor |first10=M. |last11=Mordasini |first11=C. |last12=Motalebi |first12=F. |last13=Pepe |first13=F. |last14=Queloz |first14=D. |last15=Santos |first15=N. C. |last16=Wyttenbach |first16=A. |last17=Alonso |first17=R. |last18=Collier Cameron |first18=A. |last19=Deleuil |first19=M. |last20=Figueira |first20=P. |last21=Gillon |first21=M. |last22=Moutou |first22=C. |last23=Pollacco |first23=D. |last24=Pompei |first24=E. |journal=Astronomy & Astrophysics |volume=622 |pages=A37 |bibcode=2019A&A...622A..37U }}

|rotation=38.9{{±|4}} d

| rotational_velocity = {{Val|2.216|0.273}}

| age_gyr = {{Val|5.3|2.8|2.6}}

}}

{{Starbox catalog

| names = {{odlist | CD=-72°148 | HD=20003 | HIP=14530 | SAO=255959|2MASS=J21281220-2143340}}

}}

{{Starbox reference

| Simbad = HD+20003

| NSTED = HD 20003

| EPE = HD+20003

}}

{{Starbox end

}}

HD 20003 is a star in the southern constellation Hydrus. With an apparent visual magnitude of 8.39, this yellow-hued star is much too faint to be visible to the naked eye. It is located at a distance of 136.6 light years from the Sun based on parallax. HD 20003 is drifting closer with a radial velocity of −16 km/s, and is predicted to come to within {{Convert|29.81|pc|ly|0|disp=out|abbr=off}} in around 1.4 million years from now.

This object is an ordinary, G-type main-sequence star with a stellar classification of G8 V. It is around five billion years old with a magnetic activity cycle lasting about ten years and a projected rotational velocity of 2.2 km/s. The star has 94% of the mass of the Sun and 92% of the Sun's radius. The metallicity of this star is similar to the Sun, if slightly higher. It is radiating 70.5% of the luminosity of the Sun from its photosphere at an effective temperature of 5,510 K.

The survey in 2015 have ruled out the existence of any stellar companions at projected distances above 18 astronomical units.{{cite journal |last1=Mugrauer |first1=M. |last2=Ginski |first2=C. |title=High-contrast imaging search for stellar and substellar companions of exoplanet host stars |journal=Monthly Notices of the Royal Astronomical Society |date=12 May 2015 |volume=450 |issue=3 |pages=3127–3136 |doi=10.1093/mnras/stv771 |bibcode=2015MNRAS.450.3127M |url=https://academic.oup.com/mnras/article/450/3/3127/1063872 |accessdate=19 June 2020|doi-access=free |hdl=1887/49340 |hdl-access=free }}