NY Virginis is a
binary star about 1,940 light-years away. The primary belongs to the rare class of
subdwarf B stars, being former
red giants with their
hydrogen envelope completely stripped by a stellar companion. The companion is a
red dwarf star.[8] The binary nature of NY Virginis was first identified in 1998,[9] and the extremely short orbital period of 0.101016d, together with brightness variability on the timescale of 200 seconds was noticed, resulting in the identification of the primary star as a
B-type subdwarf in 2003.[10] Under a proposed classification scheme for hot subdwarfs it would be class sdB1VII:He1. This non-standard system indicates that it is a "normal" luminosity for a hot subdwarf and that the spectrum is dominated by hydrogen rather than helium.[11]
Planetary system
In 2011, variations in the timing of the binary star's eclipses were used to infer the presence of a
superjovian planet, NY Virginis (AB) b, on a wide orbit, with a second planet being suspected.[12] A study in 2014 found that a two-planet model was preferred. The orbits of these two planets are near or at a 3:10 mutual
orbital resonance.[7] Another two-planet model with significant
orbital eccentricity, updated to account for changes in eclipse timing not predicted by previous models, was published in 2019.[4]
Studies in 2022 have noted that since planetary models generally fail to predict subsequent changes in eclipse timing,[13] and the most recent two-planet model as of 2021 results in orbits that are unstable on an astronomically-short timescale,[14][15] a different explanation for the eclipse timing variations may be needed.
^
abSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs.
Bibcode:
2009yCat....102025S.
^
abcLee, Jae Woo; Hinse, Tobias Cornelius; Youn, Jae-Hyuck; Han, Wonyong (2014). "The Pulsating sdB+M Eclipsing System NY Virginis and its Circumbinary Planets". Monthly Notices of the Royal Astronomical Society. 445 (3): 2331–2339.
arXiv:1409.4907.
Bibcode:
2014MNRAS.445.2331L.
doi:
10.1093/mnras/stu1937.
S2CID119173891.