HD 173977: An ellipsoidal <i>δ</i> Scuti star variable

Chapellier, E.; Mathias, P.; Garrido, R.; Contel, J. M. Le; Sareyan, J. P.; Ribas, I.; Parrao, L.; Moya, A.; Peña, J. H.; Álvarez, M.

doi:10.1051/0004-6361:20034068

Cited by 17 publications

(15 citation statements)

References 12 publications

(14 reference statements)

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“…The one prime candidate so far that could not be confirmed as a Doradus star is HD 173977. found it to be a short-period binary and suggested that it might be an ellipsoidal variable. Before we could publish our photometric results confirming this, Chapellier et al (2004) announced HD 173977 to be a double-lined spectroscopic binary with an orbital period of 1.801 days that also exhibits photometric variations caused by both the ellipticity effect and Scuti pulsations. This makes HD 173977 similar to HD 207651 (Henry et al 2004), which appears on Handler's further candidate list.…”

Section: The Samplementioning

confidence: 82%

Photometry and Spectroscopy of 11 γ Doradus Stars

2007

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We have used precise photometric and high-dispersion spectroscopic observations to study 11 Doradus stars, 10 of them newly confirmed. Only five of these 11 Doradus stars appear to be single; two are primaries of double-lined spectroscopic binaries, one is the secondary of a double-lined binary, two are primaries of visual binaries and, in the case of the double-lined binary (HD 86371), either or both components could be a pulsating Doradus star. We have determined a preliminary orbital period of 5.32 days for the double-lined binary HD 41547. Several of the stars show spectroscopic lineYprofile and low-amplitude radial velocity variability indicative of pulsation. All 11 stars are photometrically variable with amplitudes between 4 and 94 mmag in Johnson B and periods between 0.38 and 1.86 days. The 11 stars have between two and five independent periods. The variability at all periods approximates a sinusoid. We provide a new tabulation of all 66 Doradus stars confirmed to date and list some of their properties. All are dwarfs or subgiants and lie within a well-defined region of the H-R diagram that overlaps the cool edge of the Scuti instability strip. Four of the new Doradus variables from this paper also lie within the Scuti instability strip but do not exhibit the additional higher frequency variability typical of Scuti stars. Among the 66 confirmed Doradus variables, we find no correlation between the period of the strongest pulsation mode and the (B À V ) color index, absolute magnitude, or luminosity.

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Section: The Samplementioning

confidence: 82%

Photometry and Spectroscopy of 11 γ Doradus Stars

2007

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“…found HD 173977 to be a short-period binary and suggested it might be an ellipsoidal variable. Before we could publish our photometric results confirming this, Chapellier et al (2004) announced HD 173977 to be a double-lined spectroscopic binary with an orbital period of 1.801 days that also exhibits photometric variations caused by both the ellipticity effect and Scuti pulsations. This makes HD 173977 similar to HD 207651 ), which appears on Handler' Basic data for the 11 new Doradus stars in this study are listed in Table 1, with some of their properties determined below.…”

Section: The Samplementioning

confidence: 82%

Eleven New γ Doradus Stars

2005

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We present new high-dispersion spectroscopic and precise photometric observations to identify 11 new Doradus variables. Seven of these new Doradus stars appear to be single, three are primaries of single-lined binaries, and one has two distant visual companions; none are double-lined or close visual binaries. Several of the stars show spectroscopic line-profile and low-amplitude radial velocity variability indicative of pulsation. All 11 stars are photometrically variable with amplitudes between 8 and 93 mmag in Johnson B and periods between 0.398 and 2.454 days. One star is monoperiodic; the rest have between two and five independent periods. The variability at all periods approximates a sinusoid, although three of the stars exhibit cycle-to-cycle variation in the level of maximum brightness, similar to the Blazhko effect observed in some RR Lyrae stars. We provide a new tabulation of all 54 Doradus stars confirmed to date and list some of their properties. All are dwarfs or subgiants and lie within a well-defined region of the H-R diagram that overlaps the cool edge of the Scuti instability strip. Four of the new Doradus variables from this paper also lie within the Scuti instability strip but do not exhibit the additional higher frequency variability typical of Scuti stars. The variability type of several of these stars given in the General Catalog of Variable Stars and in SIMBAD should now be revised.

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“…These studies proposed about 60 bona fide and prime candidates stars. One star in our sample, HD 173977, which was in Handler's list (1999), has been discarded since it is now classified as a δ Scuti variable (Chapellier et al 2004). …”

Section: Introductionmentioning

confidence: 99%

Multi-site, multi-technique survey ofγ Doradus candidates

Mathias

Contel

Chapellier

et al. 2004

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Abstract. We present the first results of a 2-year high-resolution spectroscopy campaign of 59 candidate γ Doradus stars which were mainly discovered from the HIPPARCOS astrometric mission. More than 60% of the stars present line profile variations which can be interpreted as due to pulsation related to γ Doradus stars. For all stars we also derived the projected rotation velocity (up to more than 200 km s −1 ). The amplitude ratios 2K/∆m for the main HIPPARCOS frequency are in the range 35−96 km s −1 mag −1 . About 50% of the candidates are possible members of binary systems, with 20 stars being confirmed γ Doradus. At least 6 stars present composite spectra, and in all but one case (for which only one spectrum could be obtained), the narrow component shows line profile variations, pointing towards an uncomfortable situation if this narrow component originates from a shell surrounding the star. This paper is the first of a series concerning mode identification using both photometric and spectroscopic methods for the confirmed γ Doradus stars of the present sample.

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HD 173977: An ellipsoidal δ Scuti star variable

Cited by 17 publications

References 12 publications

Photometry and Spectroscopy of 11 γ Doradus Stars

Photometry and Spectroscopy of 11 γ Doradus Stars

Eleven New γ Doradus Stars

Multi-site, multi-technique survey ofγ Doradus candidates

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