Category Archives: General

For posts about the blog process or random questions.

Giant planet orbiting a white dwarf

Another day, another amazing planet! This week also saw an exciting announcement about a giant exoplanet orbiting very close to a white dwarf — possibly the first such planet discovered to survive its star’s death throes. This work was led by Andrew Vanderburg and also includes Caroline Morley and Andreia Carillo. This work used used TESS and Spitzer data, and included a high quality HET spectrum to confirm the nature of the white dwarf. This research was published Sept. 16 in Nature. You can read the press release here:

https://mcdonaldobservatory.org/news/releases/20200916a

and the full article at Nature:

https://www.nature.com/articles/s41586-020-2713-y

or the freely available version on the pre-print arXiv:

https://arxiv.org/abs/2009.07282

Hazy skies overhead and HPF discovers the first warm Jupiter around an M dwarf

In the past couple weeks we’ve noticed significant (30-60%) reductions in the amount of starlight reaching the telescope, due to the smoke overhead:

https://hwp-viz.gsd.esrl.noaa.gov/smoke/index.html

It makes the sunsets eerie and washes out the Milky Way at night, too. Hopefully this situation will improve soon! The extinction seems worst at the blue wavelengths (like those that VIRUS uses) and is not bad for redder light (HPF observations are mostly unaffected).

 

 

On the brighter side, yet another HPF paper has been accepted and published – this one is the discovery and confirmation of the first transiting ‘warm’ Jupiter around an M dwarf. You can read the HPF team’s blog post about it:

https://hpf.psu.edu/2020/09/15/toi-1899/

The PSU press release:

https://science.psu.edu/news/Mahadevan9-2020

And of course the published article itself:

https://arxiv.org/abs/2007.07098

 

Hot Jupiters are rare around M dwarfs, and transiting warm Jupiters rarer still. The TESS spacecraft only detected a single transit – and it was only with HPF that we could nail down the orbital period and mass. This one definitely highlights the power of the HET and queue! Congrats to the whole team!

A Young Sub-Neptune-sized Planet Sheds Light onto How Planets Form and Evolve

Check out the latest results from the HET! There was a press release about this fascinating discovery:

https://mcdonaldobservatory.org/news/releases/20200804

For those who want the technical information, see the accepted article on the pre-print server:  https://arxiv.org/abs/2007.12766

In short, this is a planet around a M dwarf in the Hyades cluster (so we know age and metallicity very well- both of which are tricky for M dwarfs), and is more massive  than expected- based on mass derived with HPF radial velocities. With multiple observations during transit we also have determined the spin-orbit alignment of this planet with the rotation axis of its star- which points to a well aligned orbit.
Great work to the HPF team, and the HET staff for another (massively) cool exoplanet discovery!

Welcoming our newest Resident Astronomer, and a new HPF publication

This week we’re welcoming our newest Resident Astronomer to the HET staff. Dr. Syed Uddin comes to us from a postdoc position at the Carnegie Observatories. He has studied and worked in Bangladesh, Sweden, Australia, China, and the USA, and is a valuable addition to the team. He will be working remotely for the time being, given the current situation with COVID-19 in Texas. All of the Resident Astronomers have been working remotely since March, so we are well-adjusted to this mode now.

 

Also of note this week is a new HPF paper accepted for publication:

HPF discovers a warm super Neptune – TOI-1728b

TOI-1728b: The Habitable-zone Planet Finder confirms a warm super Neptune orbiting an M dwarf host

This result was obtained using time from both UT and PSU programs, and is the latest in a recent deluge of recent publications. Congrats to Shubham and the whole HPF team!

New results from HPF: planets vs starspots!

The HPF team recently had another publication accepted describing the amazing complexities involved in separating star spots from planets. Their herculean efforts are described on this blog post and in their publication, both linked below:

https://ui.adsabs.harvard.edu/abs/2020arXiv200509657R/abstract

https://arxiv.org/abs/2005.09657

Eternal spotshine of the spinning red suns

70 VIRUS units on sky

This week the VIRUS spectrograph reached another milestone with 70 active units on sky. Below is a reconstructed/magnified image of one observation (the units actually have gaps between them but are shown magnified here). White squares show the locations for 8 remaining units.

Each dithered VIRUS observation now contains 31,000 spectra covering 46 square arcminutes. Next stop: the full 78 units!

 

New FeAr lamp

After the our Iron-Argon (FeAR) lamp started showing significantly reduced flux, on April 6th our team replaced the bulb in our Facility Calibration Unit (which rides along on the tracker, supplying continuum and line lamps for all the instruments). The new FeAr lamp is back to full brightness and provides excellent narrow emissions lines for our wavelength solutions on the Low Resolution Spectrograph #2.

 

The old bulb (left) looks quite dark and cloudy compared to the new one (right):

FeAr lamp

HET still operating, partially remotely

In response to COVID-19, the HET operations team has been rapidly developing our remote observing capabilities. At present, the night observations are staffed by one telescope operator on site and a remotely-connected resident astronomer (staying at home). Our afternoon operations shift is also being staffed remotely (one remote TO and one remote RA), requiring about 20-30 minutes of assistance from one member of day staff on site for our routine safety checks. Some day time staff are able to work partially or fully remotely from home, but most are still coming in daily as their duties cannot be done over a remote connection. Extra attention is being paid to hygiene, cleanliness, and staff presence each day. To further minimize risk, we have temporarily suspended our schedule of primary mirror segment swaps, as that process requires two members of the mirror team working in very close proximity with each other. We are benefiting from a lot of “can-do” attitudes here and receiving extensive help from our software team to get remote access and learning a lot in this process! After this is all over, I expect we’ll see long-term benefits from the things we have learned throughout this interesting time.