Massive unseen compact companions to hot subluminous stars
Final Report Abstract
During the period of time reported here the DFG-funded project yielded important results for our understanding of the late phases of binary star evolution. The MUCH-FUSS project aimed at finding hot subdwarf stars with massive compact companions. Hot subdwarf stars with high RV variations were selected as candidates for follow-up spectroscopy and photometry to derive the radial velocity curves and the binary mass functions of the systems. The photometric campaign was initiated mainly at the Calar Alto, 2.2m telescope using the BUSCA 4-channel imager. The project had a large impact on the research field by extending the sample of known systems considerably allowing us to constrain population synthesis models. Individual highlights were the discovery of substellar companions, a hyper-velocity binary, a triple system, and the first sdO to host a a compact companion in a close orbit. Irregular radial velocity variations observed in a few sdO stars still remain a riddle. Because the stellar sample on average is fainter than previous ones, that the stars are more distant, we shall be able to identify the halo population of such systems making use of Gaia astrometry very soon by exploiting the second Gaia data release.
Publications
- 2014, ”Binaries discovered by the MUCH-FUSS project. SDSS J162256.66+473051.1: An eclipsing subdwarf B binary with a brown dwarf companion”, A&A 564A, 98
Schaffenroth, V. and Geier, S. and Heber, U. and Kupfer, T. and Ziegerer, E. and Heuser, C. and Classen, L. and Cordes, O.
(See online at https://doi.org/10.1051/0004-6361/201423377) - 2014, ”Orbital solutions of eight close sdB binaries and constraints on the nature of the unseen companions”,A&A, 562, A95
Geier, S., Østensen, R. H., Heber, U., Kupfer, T., Maxted, P. F. L., Barlow, B. N., Vučković , M., Tillich, A., Müller, S.,Edelmann, H., Classen, L., McLeod, A. F.
(See online at https://doi.org/10.1051/0004-6361/201323115) - 2015, ”Hot subdwarf binaries from the MUCHFUSS project. Analysis of 12 new systems and a study of the short-period binary population”, A&A 576, 44
Kupfer, T., Geier, S., Heber, U., Østensen, R. H., Barlow, B. N., Maxted, P. F. L., Heuser, C., Schaffenroth, V., Gänsicke, B. T.
(See online at https://doi.org/10.1051/0004-6361/201425213) - 2015, ”The catalogue of radial velocity variable hot subluminous stars from the MUCHFUSS project”, A&A 577, A2
Geier, S., Kupfer, T., Heber, U., Schaffenroth, V. Barlow, B. N., Østensen, R. H., O’Toole, S. J., Ziegerer, E., Heuser, C, et al.
(See online at https://doi.org/10.1051/0004-6361/201525666) - 2016, ”An Extremely Fast Halo Hot Subdwarf Star in a Wide Binary System”, ApJ 821, L13
Németh, P., Ziegerer, E., Irrgang, A., Geier, S., Fürst, F., Kupfer, T., Heber, U.
(See online at https://doi.org/10.3847/2041-8205/821/1/L13) - 2016, ”Hot subdwarf stars and their connection to thermonuclear supernovae", Journal of Physics Conference Series, 728, 072017
Geier, S., Kupfer, T., Ziegerer, E., Heber, U., Németh, P., Irrgang, A. and MUCHFUSS team
(See online at https://doi.org/10.1088/1742-6596/728/7/072017) - 2016, ”Radial velocity variable, hot post-AGB stars from the MUCHFUSS project. Classification, atmospheric parameters, formation scenarios”, A&A, 587, 101
Reindl, N., Geier, S.,Kupfer, T., Bloemen, S., Schaffenroth, V., Heber, U., et al.
(See online at https://doi.org/10.1051/0004-6361/201527637) - 2017, ”Close Binary Progenitors, Ejected Companions of Thermonuclear Supernovae”, ASPC 509, 79
Geier, S., Kupfer, T., Heber, U., Németh, P., Ziegerer, E., Irrgang, A., Schindewolf, M., Marsh, T. R., Gänsicke, B. T., Barlow, B. N., Bloemen, S.
- 2018, ”The MUCHFUSS photometric campaign”, A&A 614, A77
Schaffenroth, V., Geier, S., Heber, U., Gerber, R., Schneider, D., Ziegerer, E., Cordes, O.
(See online at https://doi.org/10.1051/0004-6361/201629789)
