Blue Large-Amplitude Pulsator

Blue Large-Amplitude Pulsator (BLAP) is a name proposed by a Polish group of scientists for rare pulsation-variable stars whose light curve is similar to that of Cepheid and RR Lyrae stars with periods of 20 to 40 minutes at an amplitude of 0.2 to 0.4  likes . The surface temperature is around 30,000 K and a change in temperature over the cycle excludes a change in the overhead light . After subtracting the interstellar extinction , the BLAPs show a large scatter in the color-brightness diagram , which is unusual for a class of pulsating variable stars.

These stars have so far only been found by the OGLE project in the galactic bulge of the Milky Way . A search in the Magellanic Clouds was unsuccessful. They show a low metallicity and a high proportion of helium in their atmospheres . The luminosity is on the order of a hundred times that of the sun . The absolute brightness is +1 mag.

development

The pulsation periods of the BLAPs are highly stable. Theoretical models suggest that this star class

• Stars of solar mass with an active helium core
• Stars of 0.3 solar masses with a hydrogen-burning shell around an inactive helium core
• Precursors of white dwarfs extremely low mass (low mass Extremly white dwarfs) are as a result of interacting double star

Web links

• Paul Heeren: BLAP - a new class of variable stars Spektrum.de from June 26, 2017
• Rainer Kayser: New star type discovered on weltderphysik.de on June 26, 2017
• BLAPs remain mysterious Press release of the University of Erlangen-Nuremberg from July 4, 2017 on astronews.com

Individual evidence

1. ↑ P. Pietrukowicz et al .: Blue large-amplitude pulsators as a new class of variable stars . In: Astrophysics. Solar and Stellar Astrophysics . 2017, arxiv : 1706.07802v1 .
2. ^ Gavin Ramsay: Identifying Blue Large Amplitude Pulsators in the Galactic Plane using Gaia DR2: a case study . In: Astrophysics. Solar and Stellar Astrophysics . 2018, arxiv : 1811.09522v1 .
3. ↑ P. Pietrukowicz: On the Properties of Blue Large-Amplitude Pulsators. No BLAPs in the Magellanic Clouds . In: Astrophysics. Solar and Stellar Astrophysics . 2018, arxiv : 1802.04405v1 .
4. ↑ Alejandra D. Romero, AH Córsico, LG Althaus, I. Pelisoli, SO Kepler: On the evolutionary status and pulsations of the recently discovered Blue Large-Amplitude Pulsators (BLAPs) . In: Astrophysics. Solar and Stellar Astrophysics . 2018, arxiv : 1803.09600v1 .
5. ↑ Tao Wu, Yan Li: Which evolutionary status does the Blue Large-Amplitude Pulsators stay at? In: Astrophysics. Solar and Stellar Astrophysics . 2018, arxiv : 1805.07073v1 .