Papers by Konstantin Grankin
Publications of the Astronomical Society of the Pacific, 2007
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The Astronomical Journal
Exploring the properties of exoplanets near or inside the radius valley provides insight on the t... more Exploring the properties of exoplanets near or inside the radius valley provides insight on the transition from the rocky super-Earths to the larger, hydrogen-rich atmosphere mini-Neptunes. Here, we report the discovery of TOI-1452b, a transiting super-Earth (R p = 1.67 ± 0.07 R ⊕) in an 11.1 day temperate orbit (T eq = 326 ± 7 K) around the primary member (H = 10.0, T eff = 3185 ± 50 K) of a nearby visual-binary M dwarf. The transits were first detected by the Transiting Exoplanet Survey Satellite, then successfully isolated between the two 3.″2 companions with ground-based photometry from the Observatoire du Mont-Mégantic and MuSCAT3. The planetary nature of TOI-1452b was established through high-precision velocimetry with the near-infrared SPIRou spectropolarimeter as part of the ongoing SPIRou Legacy Survey. The measured planetary mass (4.8 ± 1.3 M ⊕) and inferred bulk density ( 5.6 − 1.6 + 1.8 g cm−3) is suggestive of a rocky core surrounded by a volatile-rich envelope. More qu...
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The Astrophysical Journal, 2020
For the active T-Taur star RW Aur A we have performed long-term (~10 yr) monitoring observations ... more For the active T-Taur star RW Aur A we have performed long-term (~10 yr) monitoring observations of (1) jet imaging in the [Fe II] 1.644-micron emission line using Gemini-NIFS and VLT-SINFONI; (2) optical high-resolution spectroscopy using CFHT-ESPaDOnS; and (3) V-band photometry using the CrAO 1.25-m telescope and AAVSO. The latter two observations confirm the correlation of time variabilities between (A) the Ca II 8542 A and O I 7772 A line profiles associated with magnetospheric accretion, and (B) optical continuum fluxes. The jet images and their proper motions show that four knot ejections occurred at the star over the past ~15 years with an irregular interval of 2-6 years. The time scale and irregularity of these intervals are similar to those of the dimming events seen in the optical photometry data. Our observations show a possible link between remarkable (Delta_V < -1 mag.) photometric rises and jet knot ejections. Observations over another few years may confirm or rejec...
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Astronomy & Astrophysics
Context. The so-called dippers are pre-main-sequence objects that accrete material from their cir... more Context. The so-called dippers are pre-main-sequence objects that accrete material from their circumstellar disks through the stellar magnetosphere. Their unique type of variability allows us to probe the magnetic star-disk interaction processes in young stellar objects. Aims. We aim to characterize the magnetospheric accretion process in the young stellar object V807 Tau, one of the most stable dippers revealed by K2 in the Taurus star forming region. Methods. We performed photometric and spectropolarimetric follow-up observations of this system with CFHT/ESPaDOnS in order to investigate the variability of the system over several rotational periods. Results. We derive a 4.38 day period from the K2 dipper light curve. This period is also seen in the radial velocity variations, which we ascribe to spot modulation. The slightly redshifted narrow component of the He I 5876 Å line as well as the high velocity red wing of the Hβ and Hγ emission line profiles also vary in intensity with t...
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The Astrophysical Journal
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The Astrophysical Journal
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Grb Coordinates Network, 2011
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Astronomy & Astrophysics - ASTRON ASTROPHYS, 1994
New UBVR photometry of FK Comae Berenices shows that the concentrated part of the spot distributi... more New UBVR photometry of FK Comae Berenices shows that the concentrated part of the spot distribution has shifted to a new active longitude, which is consistent with the recently defined 'flip-flop' ephemeris for a quarter of a century of photometry. The new 'flip-flop' of FK Comae Berenices is the fourth one detected during 26.3 years.
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Monthly Notices of …, 2005
... such as the Mount Wilson survey (Merrill &amp;amp; Burwell 1933, 1949), the Bosscha surve... more ... such as the Mount Wilson survey (Merrill &amp;amp; Burwell 1933, 1949), the Bosscha surveys (Thé ... MWC 930 has also been observed in the course of the All Sky Automated Survey (ASAS ... Conversion of the spectrum with the JHK bandpasses gives the following brightness of MWC 930 ...
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ABSTRACT
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Astronomy Letters
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Papers by Konstantin Grankin