HD 203949 explained

HD 203949 is a K-type giant star 257 light-years away in the constellation of Microscopium. Its surface temperature is 4618 K. It is either on the red giant branch fusing hydrogen in a shell around a helium core, or more likely a red clump star currently fusing helium in its core.^[1] HD 203949 is enriched in heavy elements relative to the Sun, with a metallicity ([Fe/H]) of . As is common for red giants, HD 203949 has an enhanced concentration of sodium and aluminium compared to iron.^[1]

Multiplicity surveys did not find any stellar companions around HD 203949 as of 2019.^[2]

Planetary system

In 2014, one planet orbiting HD 203949 was discovered by the radial velocity method.^[3] The planet is highly unlikely to have survived the red giant stage of stellar evolution on the present orbit. It is likely to be recently scattered from a wider orbit.^[1]

The planetary system configuration is favourable for direct imaging of exoplanets in the near future, and was included in the top ten easiest targets known by 2018.^[4]

Notes and References

1. 1909.05961 . 10.3847/1538-4357/ab44a8 . TESS Asteroseismology of the Known Red-giant Host Stars HD 212771 and HD 203949 . 2019 . Campante . Tiago L. . Corsaro . Enrico . Lund . Mikkel N. . Mosser . Benoît . Serenelli . Aldo . Veras . Dimitri . Adibekyan . Vardan . Antia . H. M. . Ball . Warrick . Basu . Sarbani . Bedding . Timothy R. . Bossini . Diego . Davies . Guy R. . Mena . Elisa Delgado . García . Rafael A. . Handberg . Rasmus . Hon . Marc . Kane . Stephen R. . Kawaler . Steven D. . Kuszlewicz . James S. . Lucas . Miles . Mathur . Savita . Nardetto . Nicolas . Nielsen . Martin B. . Pinsonneault . Marc H. . Reffert . Sabine . Aguirre . Víctor Silva . Stassun . Keivan G. . Stello . Dennis . Stock . Stephan . The Astrophysical Journal . 885 . 1 . 31 . 2019ApJ...885...31C . 202572968 . 1 . free .
2. 1903.02332 . 10.1093/mnras/stz671 . A high binary fraction for the most massive close-in giant planets and brown dwarf desert members . 2019 . Biller . B. . Mužić . K. . Lopez . E. . Bonavita . M. . Rice . K. . Fontanive . C. . Monthly Notices of the Royal Astronomical Society . 485 . 4 . 4967–4996 .
3. 1406.0884 . 10.1051/0004-6361/201323345 . The properties of planets around giant stars . 2014 . Jones . M. I. . Jenkins . J. S. . Bluhm . P. . Rojo . P. . Melo . C. H. F. . Astronomy & Astrophysics . 566 . A113 . 2014A&A...566A.113J . 118396750 .
4. 1802.06252 . 10.1051/0004-6361/201832847 . Kernel-nulling for a robust direct interferometric detection of extrasolar planets . 2018 . Martinache . Frantz . Ireland . Michael J. . Astronomy & Astrophysics . 619 . A87 . 2018A&A...619A..87M . 118882482 .