TY - JOUR
T1 - New radial velocity observations of AH Her
T2 - Evidence for material outside the tidal radius
AU - Echevarriá, J.
AU - Hernández Santisteban, J. V.
AU - Segura Montero, O.
AU - Ramírez, S. H.
AU - Ruelas-Mayorga, A.
AU - Sánchez, L. J.
AU - Michel, R.
AU - Costero, R.
AU - González-Buitrago, D. H.
AU - Olivares, J.
N1 - The authors acknowledge financial support prom PAPIIT project IN114917. JER acknowledges support from a ‘Leids Kerkhoven-Bosscha Fonds’ (LKBF) travel grant to visit the API at UvA. LJS and ARM would like to thank DGAPA, UNAM for financial support provided by Programa de Apoyo a Proyecto de Investigacion e Inovacion Tecnologica (PAPIIT) projects IN102517andIN102617. JVHS acknowledges support from an STFC grant ST/R000824/1.
PY - 2021/2/1
Y1 - 2021/2/1
N2 - Spectroscopic observations of AH Herculis during a deep quiescent state are put forward. We found the object in a rare long minima, allowing us to derive accurately the semi-amplitudes: K1 =121 ± 4 km s-1 and K2 = 152 ± 2 km s-1 and its mass functions MWsin 3i = 0.30 ± 0.01 M⊙ and MRsin 3i = 0.24 ± 0.02 M⊙, while its binary separation is given by asin i = 1.39 ± 0.02 R⊙. The orbital period Porb = 0.25812 ± 0.00032 d was found from a power spectrum analysis of the radial velocities of the secondary star. These values are consistent with those determined by Horne, Wade & Szkody. Our observations indicate that K5 is the most likely spectral type of the secondary. We discuss why we favour the assumption that the donor in AH Her is a slightly evolved star, in which case we find that the best solution for the inclination yields i = 48° ± 2°. None the less, should the donor be a ZAMS star, we obtain that the inclination is between i = 43° and i = 44°. We also present Doppler tomography of H α and H β, and found that the emission in both lines is concentrated in a large asymmetric region at low velocities, but at an opposite position to the secondary star, outside the tidal radius and therefore at an unstable position. We also analyse the H α and H β line profiles, which show a single broad peak and compare it with the previous quiescent state study that shows a double-peaked profile, providing evidence for its transient nature.
AB - Spectroscopic observations of AH Herculis during a deep quiescent state are put forward. We found the object in a rare long minima, allowing us to derive accurately the semi-amplitudes: K1 =121 ± 4 km s-1 and K2 = 152 ± 2 km s-1 and its mass functions MWsin 3i = 0.30 ± 0.01 M⊙ and MRsin 3i = 0.24 ± 0.02 M⊙, while its binary separation is given by asin i = 1.39 ± 0.02 R⊙. The orbital period Porb = 0.25812 ± 0.00032 d was found from a power spectrum analysis of the radial velocities of the secondary star. These values are consistent with those determined by Horne, Wade & Szkody. Our observations indicate that K5 is the most likely spectral type of the secondary. We discuss why we favour the assumption that the donor in AH Her is a slightly evolved star, in which case we find that the best solution for the inclination yields i = 48° ± 2°. None the less, should the donor be a ZAMS star, we obtain that the inclination is between i = 43° and i = 44°. We also present Doppler tomography of H α and H β, and found that the emission in both lines is concentrated in a large asymmetric region at low velocities, but at an opposite position to the secondary star, outside the tidal radius and therefore at an unstable position. We also analyse the H α and H β line profiles, which show a single broad peak and compare it with the previous quiescent state study that shows a double-peaked profile, providing evidence for its transient nature.
KW - Techniques: radial velocities
KW - Techniques: spectroscopic
KW - Stars: individual: AH Her
KW - Novae
KW - Cataclysmic variables
U2 - 10.1093/mnras/staa3615
DO - 10.1093/mnras/staa3615
M3 - Article
AN - SCOPUS:85100416791
SN - 0035-8711
VL - 501
SP - 596
EP - 605
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -