HERMES High-Resolution Spectroscopy of HD 149382—Where Did the Planet Go?

Jacobs, Valery A.; O̸stensen, Roy H.; Winckel, H. Van; Bloemen, S.; Pápics, P. I.; Raskin, Gert; Debosscher, J.; Uttenthaler, S.; Aarle, E. van; Waelkens, Christoffel; Bauwens, E; Verhoelst, Tijl; Gielen, C.; Lehmann, H.; Oreiro, R.; Schuh, S.; Drechsel, H.; Heber, U.

doi:10.1063/1.3570991

Cited by 2 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We take for this star (which is not in the halo) the maximum radius on the RGB to be 0.5AU , hence a 0 1.5 AU (Nordhaus et al 2010). Recently a different study by Jacobs et al 2010, did not find the planet. Jacobs et al (2010) analyzed He lines while Geier et al (2009) analyzed metal lines.…”

Section: Implications For the Formation Of Ehb (Sdo Sdb) Starsmentioning

confidence: 96%

“…Recently a different study by Jacobs et al 2010, did not find the planet. Jacobs et al (2010) analyzed He lines while Geier et al (2009) analyzed metal lines. Although the existence of this planet is now questionable (and hopefully will be resolved soon by the observers listed above), it does not change our conclusions.…”

Section: Implications For the Formation Of Ehb (Sdo Sdb) Starsmentioning

confidence: 96%

See 1 more Smart Citation

Connecting planets around horizontal branch stars with known exoplanets

Bear

Soker

2010

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We study the distribution of exoplanets around main sequence (MS) stars and apply our results to the binary model for the formation of extreme horizontal branch (EHB; sdO; sdB; hot subdwarfs) stars. By Binary model we refer both to stellar and substellar companions that enhance the mass loss rate, where substellar companions stand for both massive planets and brown dwarfs. We conclude that sdB (EHB) stars are prime targets for planet searches. We reach this conclusion by noticing that the bimodal distribution of planets around stars with respect to the parameter M_p*a^2, is most prominent for stars in the mass range 1Mo < M < 1.5Mo; 'a' is the orbital separation, 'M' is the stellar mass and 'M_p' the planet mass. This is also the mass range of the progenitors of EHB stars that are formed through the interaction of their progenitors with planets (assuming the EHB formation mechanism is the binary model). In the binary model for the formation of EHB stars interaction with a binary companion or a substellar object (a planet or a brown dwarf), causes the progenitor to lose most of its envelope mass during its red giant branch (RGB) phase. As a result of that the descendant HB star is hot, i.e., an EHB (sdB) star. The bimodal distribution suggests that even if the close-in planet that formed the EHB star did not survive its RGB common envelope evolution, one planet or more might survive at a>1AU. Also, if a planet or more are observed at a>1AU, it is possible that a closer massive planet did survive the common envelope phase, and it is orbiting the EHB with an orbital period of hours to days.Comment: MNRAS, in pres

show abstract

Section: Implications For the Formation Of Ehb (Sdo Sdb) Starsmentioning

confidence: 96%

Section: Implications For the Formation Of Ehb (Sdo Sdb) Starsmentioning

confidence: 96%

Connecting planets around horizontal branch stars with known exoplanets

Bear

Soker

2010

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…In their Table 1, Silvotti et al (2011) list the currently known post-RGB exoplanetary systems (with the addition of brown dwarf companions to complete the picture of substellar companions). A controversial discussion whether or not the sdB HD 149382 has a substellar companion can be found in Geier et al (2009a) and Jacobs et al (2011). Also the pulsating DAV white dwarf GD 66 is a promising yet unconfirmed candidate to harbor a substellar companion (Mullally, 2007;Mullally et al, 2008Mullally et al, , 2009.…”

Section: Planetary Systems Around Evolved Starsmentioning

confidence: 99%

The search for substellar companions to subdwarf B stars in connection with evolutionary aspects

Lutz¹

View full text Add to dashboard Cite

The formation and evolution of hot subluminous B stars (sdB stars in the following) is not entirely understood. Although the current evolutionary status, i. e. the position in the Hertzsprung-Russell diagram, can be characterized and interpreted quite well, the preceding evolution of these objects remains uncertain. Since sdB stars do not follow a standard evolution of low mass stars, there must have been some event or phase in their history which led to a departure of the standard description. It is well-established in the literature that this event is connected to an enhanced mass loss of the sdB progenitor star during its red giant phase. This enhanced mass loss is a prerequisite to explain the very existence of sdB stars, its cause is, however, matter of debate. In the case of subdwarf B stars in binary systems, formation scenarios invoking Roche-lobe overflow and common envelope evolution are most promising. Theory and observations agree quite well in this case. However, there are some issues concerning single sdB stars, i. e. such stars which are not part of a binary system and therefore do not have a stellar companion. Such single sdB stars are an integral part of this thesis. One particular hypothesis discussed in the literature predicts that even substellar companions like brown dwarfs or exoplanets may be able to have a decisive influence on the formation of single sdB stars. A major goal of this present thesis is to investigate this hypothesis by searching for substellar companions to subdwarf B stars. Another goal is to pin down the evolutionary status of the investigated sdB stars and to directly measure their evolutionary timescales. The precise purposes are hence the search for substellar companions and the determination of evolutionary timescales. To achieve the goals mentioned above, the so-called EXOTIME program has been set up. EXOTIME conducts a long-term monitoring of five pulsating sdB stars with means of ground based time-resolved relative photometry. xi I will motivate the basic questions and intentions which led to the idea of setting up this thesis and to investigate the subdwarf B stars with respect to substellar companions. Chapter three is intended to introduce the purpose and goals of the EXOTIME project and to briefly characterize the target stars central to this thesis. Subsequently, in chapter four I will present the data archive built up during the last years, with a special emphasis on the observation facilities and observational strategy. Chapter five provides a description of the methods being applied to investigate the subdwarf B stars for substellar companions. A focus is set on the O-C timing method and a comparison to various other exoplanet detection methods. The results of the analysis are extensively presented in chapter six. Chapter seven will discuss these results, put them into a broader context and address various other implications and applications. A summary and outlook, as provided in chapter eight, will conclude this thesis. xiv -Miles Kington Welcome to Kington...

show abstract

HERMES High-Resolution Spectroscopy of HD 149382—Where Did the Planet Go?

Cited by 2 publications

References 5 publications

Connecting planets around horizontal branch stars with known exoplanets

Connecting planets around horizontal branch stars with known exoplanets

The search for substellar companions to subdwarf B stars in connection with evolutionary aspects

Contact Info

Product

Resources

About