A convincing Mv-W(H-gamma) calibration for A and B supergiants

Walker, G. A. H.; Millward, C. G.

doi:10.1086/162930

Cited by 12 publications

(8 citation statements)

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“…The spectra were taken over a period of 3.5 years, and the typical RV accuracy was 20 m/s. The RV variations were consistent in amplitude and phase with the older data by Walker et al (1989).…”

Section: Introductionsupporting

confidence: 82%

“…In the Hipparcos Catalogue Pollux was flagged as a possible micro-variable with a photometric amplitude of less than 0.03 mag (but no obvious periodicity), as well as a possibly non-single star, maybe because of slightly different astrometric solutions from the two different data reduction consortia. Walker et al (1989) were the first to report significant radial velocity (RV) variations for Pollux, with a standard deviation of 26 m/s around the mean from RV measurements spread over about five years. Though they noted that based on a periodogram analysis significant periodicity was present in the data, they did not quote any period.…”

Section: Introductionmentioning

confidence: 99%

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Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion

Reffert¹,

Quirrenbach²,

Mitchell

et al. 2006

ApJ

105

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It has long been speculated that the observed periodic radial velocity pattern for the K giant Pollux might be explained in terms of an orbiting planetary companion. We have collected 80 high-resolution spectra for Pollux at Lick Observatory yielding precise radial velocities with a mean error of 3.8 m/s, providing the most comprehensive and precise data set available for this star. Our data confirm the periodicity previously seen in the radial velocities. We derive a period of 589.7±3.5 days and, assuming a primary mass of 1.86 M ⊙ , a minimum companion mass of 2.9±0.3M Jup , consistent with earlier determinations. No evidence for any periodicities is visible in our analysis of the shapes of the spectral lines via the bisector method, so that we conclude that evidence is accumulating and compelling for a planet around Pollux. However, some last doubt remains about this interpretation, because non-radial pulsations which might be present in giant stars could in principle also explain the observed radial velocities, while the accompanying bisector variations might be too small to be detectable with current data.

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Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion

Reffert¹,

Quirrenbach²,

Mitchell

et al. 2006

ApJ

105

View full text Add to dashboard Cite

show abstract

“…Changes in spectral line shapes arising from motions in the stellar atmosphere, related to nonradial pulsations or inhomogeneous convection and/or spots combined with rotation can mimic low-level long period RV variations. Significant variability of red giants has been noted already by Payne-Gaposchkin (1954) and Walker et al (1989) and made the nature of these variations a topic of numerous studies. Hatzes & Cochran (1993) showed that the low-amplitude, long-period RV variations may be attributed to pulsations, stellar activity -a spot rotating with a star, or low-mass companions while the presence of short-period, possibly p-mode oscillations as demonstrated in Hatzes & Cochran (1994).…”

Section: Stellar Activity Analysis: Line Bisectors Hα Variations Andmentioning

confidence: 85%

Three Red Giants With Substellar-Mass Companions

Niedzielski

Wolszczan

Nowak

et al. 2015

ApJ

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We present three giant stars from the ongoing Penn State-Toruń Planet Search with the Hobby-Eberly Telescope, which exhibit radial velocity variations that point to a presence of planetary -mass companions around them. BD+49 828 is a M = 1.52 ± 0.22 M K0 giant with a m sin i = 1.6 +0.4 −0.2 M J minimum mass companion in a = 4.2 +0.32 −0.2 AU (2590 +300 −180 d), e = 0.35 +0.24 −0.10 orbit. HD 95127, a log L/L = 2.28 ± 0.38, R = 20 ± 9 R , M = 1.20 ± 0.22 M K0 giant has a msini=5.01 +0.61 −0.44 M J minimum mass companion in a = 1.28 +0.01 −0.01 AU (482 +5 −5 d), e = 0.11 +0.15 −0.06 orbit. Finally, HD 216536, is a M = 1.36 ± 0.38 M K0 giant with a m sin i = 1.47 +0.20 −0.12 M J minimum mass companion in a = 0.609 +0.002 −0.002 AU (148.6 +0.7−0.7 d), e = 0.38 +0.12 −0.10 orbit. Both, HD 95127 b and HD 216536 b in their compact orbits, are very close to the engulfment zone and hence prone to ingestion in the near future. BD+49 828 b is among the longest period planets detected with the radial velocity technique until now and it will remain unaffected by

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“…Hatzes & Cochran found that all three K giants in their sample, Arcturus (α Boo), Aldebaran (α Tau), and Pollux (β Gem) displayed large, periodic radial velocity variations with semiamplitudes of 50-200 m/s. Comparison with prior radial velocities obtained by Cambpell's group (Walker et al 1989) revealed that the variations were coherent over 10 years. While both α Boo and α Tau showed significant day-to-day RV variations indicative of radial pulsation modes and correlated variations in the 10830Å He i line, β Gem seemed to have a clean signal, consistent with a 554 d planet with a minimum mass of 3 M Jup .…”

Section: Hatzes and Cochran's Survey And β Gem Bmentioning

confidence: 57%

Exoplanet Detection Methods

Wright

Gaudi

2013

Planets, Stars and Stellar Systems

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This chapter reviews various methods of detecting planetary companions to stars from an observational perspective, focusing on radial velocities, astrometry, direct imaging, transits, and gravitational microlensing. For each method, this chapter first derives or summarizes the basic observable phenomena that are used to infer the existence of planetary companions, as well as the physical properties of the planets and host stars that can be derived from the measurement of these signals. This chapter then outlines the general experimental requirements to robustly detect the signals using each method, by comparing their magnitude to the typical sources of measurement uncertainty. This chapter goes on to compare the various methods to each other by outlining the regions of planet and host star parameter space where each method is most sensitive, stressing the complementarity of the ensemble of the methods at our disposal. Finally, there is a brief review of the history of the young exoplanet field, from the first detections to current state-of-the-art surveys for rocky worlds.

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A convincing Mv-W(H-gamma) calibration for A and B supergiants

Cited by 12 publications

References 0 publications

Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion

Precise Radial Velocities of Giant Stars. II. Pollux and Its Planetary Companion

Three Red Giants With Substellar-Mass Companions

Exoplanet Detection Methods

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