Calculations of periodicity from H<i>α</i>profiles of Proxima Centauri

Collins, John M.; Jones, H. R. A.; Barnes, John

doi:10.1051/0004-6361/201628827

Cited by 14 publications

(10 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These latter authors used photometric observations obtained with the Hubble Space Telescope (HST) and the automated sky survey ASAS (Pojmanski 1997;Pojmanski & Maciejewski 2004). A periodicity of 82.6 ± 0.1 days is also reported by Collins et al (2017) 2015) is likely an alias induced by the specific HARPS observation times, and concluded that the most significant rotation period of Proxima Cen is 82.6 ± 0.1 days.…”

Section: Rotational Modulation Of the Chromosphere And The Photospheresupporting

confidence: 63%

Temporal changes of the flare activity of Proxima Centauri

Pavlenko

Mascareño²,

Osorio³

et al. 2019

A&A

View full text Add to dashboard Cite

Context. We study temporal variations of the emission lines of Hα, Hǫ, H and K CaI, D1 and D2 NaI, He4026, and He5876 in the HARPS spectra of Proxima Centauri across an extended time of 13.2 years, from May 27, 2004, to September 30, 2017 Aims. We analyse the common behaviour and differences in the intensities and profiles of different emission lines in flare and quiet modes of Proxima activity. Methods. We compare the pseudo-equivalent widths (pEW ) and profiles of the emission lines in the HARPS highresolution (R ∼ 115,000) spectra observed at the same epochs. Results. All emission lines show variability with a timescale of at least 10 min. The strength of all lines except He4026 correlate with Hα. During strong flares the 'red asymmetry' appears in the Hα emission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100 km/s disturbing chromospheric layers. As a result, the strength of the Ca II lines anti-correlates with Hα during strong flares. The HeI lines at 4026 and 5876 Å appear in the strong flares. The cores of D1 and D2 NaI lines are also seen in emission. During the minimum activity of Proxima Centauri, CaII lines and Hǫ almost disappear while the blue part of the NaI emission lines is affected by the absorption in the extending and condensing flows. Conclusions. We see different behaviour of emission lines formed in the flare regions and chromosphere. Chromosphere layers of Proxima Cen are likely heated by the flare events; these layers are cooled in the 'non-flare' mode. The selfabsorption structures in cores of our emission lines vary with time due to the presence of a complicated system of inward and outward matter flows in the absorbing layers.

show abstract

Section: Rotational Modulation Of the Chromosphere And The Photospheresupporting

confidence: 63%

Temporal changes of the flare activity of Proxima Centauri

Pavlenko

Mascareño²,

Osorio³

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…The rotational period of Proxima Centauri is approximately 86 days (ref. 69), suggesting that LHS 1140 may be older than Proxima Centauri. Taken together, we suggest that LHS 1140 is likely to be greater than 5 Gyr in age.…”

Section: Rejection Of False-positive Scenariosmentioning

confidence: 99%

A temperate rocky super-Earth transiting a nearby cool star

Dittmann

Irwin

Charbonneau

et al. 2017

Nature

340

280

View full text Add to dashboard Cite

M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars. Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.5 parsecs away. A temperate planet has been discovered orbiting Proxima Centauri, the closest M dwarf, but it probably does not transit and its true mass is unknown. Seven Earth-sized planets transit the very low-mass star TRAPPIST-1, which is 12 parsecs away, but their masses and, particularly, their densities are poorly constrained. Here we report observations of LHS 1140b, a planet with a radius of 1.4 Earth radii transiting a small, cool star (LHS 1140) 12 parsecs away. We measure the mass of the planet to be 6.6 times that of Earth, consistent with a rocky bulk composition. LHS 1140b receives an insolation of 0.46 times that of Earth, placing it within the liquid-water, habitable zone. With 90 per cent confidence, we place an upper limit on the orbital eccentricity of 0.29. The circular orbit is unlikely to be the result of tides and therefore was probably present at formation. Given its large surface gravity and cool insolation, the planet may have retained its atmosphere despite the greater luminosity (compared to the present-day) of its host star in its youth. Because LHS 1140 is nearby, telescopes currently under construction might be able to search for specific atmospheric gases in the future.

show abstract

“…Collins et al (24) analyzed 13 years of spectroscopic and photometric observations and derived 82.1 days for the stellar rotation period of Proxima based on H activity index, in agreement with the period of 83 days calculated in (4) with Hubble Space Telescope (HST) photometry and confirmed in (17,25). Robertson et al (25) did not find anything relevant on longer timescales, likely as a consequence of the stochastic nature of the microflaring activity of Proxima, which dominates the H line emission and makes the analysis of this index very complex in the time domain, as already pointed out in (8).…”

Section: Is the Candidate Planetary Signal Actually Linked To The Stementioning

confidence: 99%

A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

et al. 2020

Self Cite

View full text Add to dashboard Cite

Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass mc sin ic = 5.8 ± 1.9M⊕ and orbital period Pc=5.21−0.22+0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.

show abstract

Calculations of periodicity from Hαprofiles of Proxima Centauri

Cited by 14 publications

References 35 publications

Temporal changes of the flare activity of Proxima Centauri

Temporal changes of the flare activity of Proxima Centauri

A temperate rocky super-Earth transiting a nearby cool star

A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

Contact Info

Product

Resources

About